{ "instance": { "pfg-20191231x10k0da4e5.htm": { "axisCustom": 5, "axisStandard": 50, "contextCount": 1341, "dts": { "calculationLink": { "local": [ "pfg-20191231_cal.xml" ] }, "definitionLink": { "local": [ "pfg-20191231_def.xml" ], "remote": [ "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-eedm-def-2019-01-31.xml", "http://xbrl.fasb.org/srt/2019/elts/srt-eedm1-def-2019-01-31.xml" ] }, "inline": { "local": [ "pfg-20191231x10k0da4e5.htm" ] }, "labelLink": { "local": [ "pfg-20191231_lab.xml" ], "remote": [ "http://xbrl.fasb.org/srt/2019/elts/srt-doc-2019-01-31.xml", "https://xbrl.sec.gov/dei/2019/dei-doc-2019-01-31.xml", "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-doc-2019-01-31.xml" ] }, "presentationLink": { "local": [ "pfg-20191231_pre.xml" ] }, "referenceLink": { "remote": [ "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-ref-2019-01-31.xml", "https://xbrl.sec.gov/dei/2019/dei-ref-2019-01-31.xml", "http://xbrl.fasb.org/srt/2019/elts/srt-ref-2019-01-31.xml" ] }, "schema": { "local": [ "pfg-20191231.xsd" ], "remote": [ "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd", "http://www.xbrl.org/2003/xl-2003-12-31.xsd", "http://www.xbrl.org/2003/xlink-2003-12-31.xsd", "https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd", "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd", "http://www.xbrl.org/2005/xbrldt-2005.xsd", "http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd", "http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd", "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd", "http://xbrl.fasb.org/us-gaap/2019/elts/us-roles-2019-01-31.xsd", "http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd", "http://www.xbrl.org/2006/ref-2006-02-27.xsd", "http://xbrl.fasb.org/srt/2019/elts/srt-types-2019-01-31.xsd", "http://xbrl.fasb.org/srt/2019/elts/srt-roles-2019-01-31.xsd", "https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd", "http://xbrl.fasb.org/us-gaap/2019/elts/us-types-2019-01-31.xsd", "http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd", "http://www.xbrl.org/lrr/role/deprecated-2009-12-16.xsd", "http://www.xbrl.org/lrr/role/reference-2009-12-16.xsd", "http://xbrl.fasb.org/us-gaap/2019/elts/us-parts-codification-2019-01-31.xsd" ] } }, "elementCount": 1708, "entityCount": 1, "hidden": { "http://fasb.org/us-gaap/2019-01-31": 41, "http://principal.com/20191231": 6, "http://xbrl.sec.gov/dei/2019-01-31": 6, "total": 53 }, "keyCustom": 298, "keyStandard": 779, "memberCustom": 158, "memberStandard": 158, "nsprefix": "pfg", "nsuri": "http://principal.com/20191231", "report": { "R1": { "firstAnchor": { "ancestors": [ "p", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "dei:DocumentType", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "document", "isDefault": "true", "longName": "00090 - Document - Document and Entity Information", "role": "http://principal.com/role/DocumentDocumentAndEntityInformation", "shortName": "Document and Entity Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "p", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "dei:DocumentType", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R10": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:VariableInterestEntitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10301 - Disclosure - Variable Interest Entities", "role": "http://principal.com/role/DisclosureVariableInterestEntities", "shortName": "Variable Interest Entities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:VariableInterestEntitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R100": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ShortDurationContractsDiscountedLiabilitiesAmount", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40807 - Disclosure - Insurance Liabilities - Discounting Table (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "shortName": "Insurance Liabilities - Discounting Table (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ShortDurationInsuranceContractsDiscountedLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_srt_ProductOrServiceAxis_pfg_LongTermDisabilityGroupLifeWaiverMember_V65tqgAGbkW2-0ixLDg9yw", "decimals": "-5", "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsDiscountedLiabilitiesInterestAccretion", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R101": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShortTermDebtTextBlock", "us-gaap:DebtDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40901 - Disclosure - Debt - Short-Term Debt (Details)", "role": "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "shortName": "Debt - Short-Term Debt (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShortTermDebtTextBlock", "us-gaap:DebtDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R102": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDebtInstrumentsTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtInstrumentCarryingAmount", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40902 - Disclosure - Debt - Components of Long-Term Debt (Details)", "role": "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "shortName": "Debt - Components of Long-Term Debt (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDebtInstrumentsTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R103": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:RepaymentsOfLongTermDebt", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40903 - Disclosure - Debt - Senior Notes and Junior Subordinated Notes (Details)", "role": "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails", "shortName": "Debt - Senior Notes and Junior Subordinated Notes (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_5_7_2015_To_5_7_2015_srt_RangeAxis_srt_MaximumMember_us-gaap_LongtermDebtTypeAxis_us-gaap_JuniorSubordinatedDebtMember_kInw615atEukOGgNA9py3g", "decimals": null, "lang": "en-US", "name": "pfg:YearsInterestPaymentsOnDebtDeferred", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R104": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDebtInstrumentsTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtInstrumentCarryingAmount", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40904 - Disclosure - Debt - Non-Recourse Mortgages and Notes Payable (Details)", "role": "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "shortName": "Debt - Non-Recourse Mortgages and Notes Payable (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_DebtInstrumentAxis_pfg_NonRecourseMortgagesAndNotesPayableConsolidateMember_77U1AGZXUkq9Dm4CG98Yrw", "decimals": "-5", "lang": null, "name": "pfg:DebtInstrumentCarryingAmountLowEndOfRange", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R105": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40905 - Disclosure - Debt - Future Maturities of Long-Term Debt (Details)", "role": "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails", "shortName": "Debt - Future Maturities of Long-Term Debt (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R106": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_3_8_2018_To_3_8_2018_us-gaap_FinancialInstrumentAxis_pfg_ContingentFundingAgreementMember_JsrLvQ083k2AbB2Kq0fZ3Q", "decimals": "INF", "first": true, "lang": null, "name": "pfg:NumberOfContingentFundingAgreements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_j5ZbdD4KskmT0NnezP59Og", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40906 - Disclosure - Debt - Contingent Funding Agreements (Details)", "role": "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "shortName": "Debt - Contingent Funding Agreements (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_3_8_2018_To_3_8_2018_us-gaap_FinancialInstrumentAxis_pfg_ContingentFundingAgreementMember_JsrLvQ083k2AbB2Kq0fZ3Q", "decimals": "INF", "first": true, "lang": null, "name": "pfg:NumberOfContingentFundingAgreements", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_j5ZbdD4KskmT0NnezP59Og", "xsiNil": "false" } }, "R107": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock", "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:CurrentFederalTaxExpenseBenefit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41001 - Disclosure - Income Taxes - Income Tax Expense and Income Before Income Taxes (Details)", "role": "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails", "shortName": "Income Taxes - Income Tax Expense and Income Before Income Taxes (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock", "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:CurrentFederalTaxExpenseBenefit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R108": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate", "reportCount": 1, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41002 - Disclosure - Income Taxes - Effective Income Tax Rate (Details)", "role": "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails", "shortName": "Income Taxes - Effective Income Tax Rate (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "2", "lang": null, "name": "us-gaap:EffectiveIncomeTaxRateReconciliationDeductionsDividends", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R109": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:SummaryOfIncomeTaxContingenciesTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:UnrecognizedTaxBenefits", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41003 - Disclosure - Income Taxes - Unrecognized Tax Benefits (Details)", "role": "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails", "shortName": "Income Taxes - Unrecognized Tax Benefits (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:SummaryOfIncomeTaxContingenciesTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_QrVbGqN2iEGfyKBqKo9U6A", "decimals": "-5", "lang": null, "name": "us-gaap:UnrecognizedTaxBenefits", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R11": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:InvestmentsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10401 - Disclosure - Investments", "role": "http://principal.com/role/DisclosureInvestments", "shortName": "Investments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:InvestmentsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R110": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate", "reportCount": 1, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41004 - Disclosure - Income Taxes - Deferred Income Taxes and Other (Details)", "role": "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails", "shortName": "Income Taxes - Deferred Income Taxes and Other (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "pfg:DeferredTaxAssetsInvestmentIncludingDerivativeLiabilities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R111": { "firstAnchor": { "ancestors": [ "p", "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_4nmKGANgb0633vovMejdxA", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41101 - Disclosure - Employee and Agent Benefits - Plan Information (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "shortName": "Employee and Agent Benefits - Plan Information (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_4nmKGANgb0633vovMejdxA", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R112": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_dZ45WrMjsk297LPX0JyneA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanBenefitObligation", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41102 - Disclosure - Employee and Agent Benefits - Benefit Obligation and Funded Status (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "shortName": "Employee and Agent Benefits - Benefit Obligation and Funded Status (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_4nmKGANgb0633vovMejdxA", "decimals": "-5", "lang": null, "name": "us-gaap:DefinedBenefitPlanBenefitObligationBenefitsPaid", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R113": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_5_31_2019_To_5_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_YcCiURD3OE6tNcrE9lSdDg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanActuarialGainLoss", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41103 - Disclosure - Employee and Agent Benefits - Pension Plan Changes and Plan Gains/Losses (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "shortName": "Employee and Agent Benefits - Pension Plan Changes and Plan Gains/Losses (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_5_31_2019_To_5_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_YcCiURD3OE6tNcrE9lSdDg", "decimals": "-5", "lang": null, "name": "pfg:DefinedBenefitPlanTotalPlanAmendmentGainLossRecordedInAoci", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R114": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2017_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MCUbCUygHUOBkR2m2FpoFw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossBeforeTaxFromCurrentYearAmendments", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41104 - Disclosure - Employee and Agent Benefits - ABO in Excess of Plan Assets (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "shortName": "Employee and Agent Benefits - ABO in Excess of Plan Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "-5", "lang": null, "name": "us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R115": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "INF", "first": true, "lang": null, "name": "pfg:DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41105 - Disclosure - Employee and Agent Benefits - Net Periodic Benefit Cost (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "shortName": "Employee and Agent Benefits - Net Periodic Benefit Cost (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "INF", "first": true, "lang": null, "name": "pfg:DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R116": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "4", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate", "reportCount": 1, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41106 - Disclosure - Employee and Agent Benefits - Weighted Average Assumptions (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails", "shortName": "Employee and Agent Benefits - Weighted Average Assumptions (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "pfg:ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_dZ45WrMjsk297LPX0JyneA", "decimals": "4", "lang": null, "name": "us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R117": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanFairValueOfPlanAssets", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41107 - Disclosure - Employee and Agent Benefits - Fair Value of Plan Assets (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "shortName": "Employee and Agent Benefits - Fair Value of Plan Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAllocationOfPlanAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTaxStatusAxis_us-gaap_QualifiedPlanMember_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_eAv1RFGAzUmgtbR_xlff0g", "decimals": "-5", "lang": null, "name": "us-gaap:DefinedBenefitPlanFairValueOfPlanAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R118": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_RangeAxis_srt_MinimumMember_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_FixedIncomeSecuritiesMember_us-gaap_RetirementPlanTaxStatusAxis_us-gaap_QualifiedPlanMember_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_obHkaKQwm0yPEUXgnN5Zvw", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41108 - Disclosure - Employee and Agent Benefits - Target Plan Asset Allocation (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "shortName": "Employee and Agent Benefits - Target Plan Asset Allocation (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_RangeAxis_srt_MinimumMember_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_FixedIncomeSecuritiesMember_us-gaap_RetirementPlanTaxStatusAxis_us-gaap_QualifiedPlanMember_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_obHkaKQwm0yPEUXgnN5Zvw", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R119": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfExpectedBenefitPaymentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41109 - Disclosure - Employee and Agent Benefits - Contributions and Estimated Future Benefit Payments (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "shortName": "Employee and Agent Benefits - Contributions and Estimated Future Benefit Payments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfExpectedBenefitPaymentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R12": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10501 - Disclosure - Derivative Financial Instruments", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstruments", "shortName": "Derivative Financial Instruments", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R120": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_MsL3u7_TbEqaII91n40ssA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41110 - Disclosure - Employee and Agent Benefits - Supplemental Information, Qualified and Nonqualified Plans (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "shortName": "Employee and Agent Benefits - Supplemental Information, Qualified and Nonqualified Plans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfDefinedBenefitPensionPlansSupplementalInformationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_RetirementPlanTaxStatusAxis_us-gaap_QualifiedPlanMember_us-gaap_RetirementPlanTypeAxis_us-gaap_PensionPlansDefinedBenefitMember_eAv1RFGAzUmgtbR_xlff0g", "decimals": "-5", "lang": null, "name": "us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R121": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_shares_UgnKE16LEUiVNZpRmYQFcA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41111 - Disclosure - Employee and Agent Benefits - Defined Contribution and Deferred Compensation Plans (Details)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "shortName": "Employee and Agent Benefits - Defined Contribution and Deferred Compensation Plans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_shares_UgnKE16LEUiVNZpRmYQFcA", "xsiNil": "false" } }, "R122": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41201 - Disclosure - Contingencies, Guarantees, Indemnifications and Leases - Guarantees and Indemnifications (Details)", "role": "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails", "shortName": "Contingencies, Guarantees, Indemnifications and Leases - Guarantees and Indemnifications (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R123": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:LeaseBalanceSheetDisclosureTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:OperatingLeaseRightOfUseAsset", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41202 - Disclosure - Contingencies, Guarantees, Indemnifications and Leases - Leases (Details)", "role": "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails", "shortName": "Contingencies, Guarantees, Indemnifications and Leases - Leases (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:LeaseBalanceSheetDisclosureTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:OperatingLeaseRightOfUseAsset", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R124": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DividendsDeclaredTableTextBlock", "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember_MK8alGHPVkKNS9687RbozQ", "decimals": "INF", "first": true, "lang": null, "name": "us-gaap:CommonStockDividendsPerShareDeclared", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_USD_shares_CIpRh538OUyDxoUsVt6tLg", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41301 - Disclosure - Stockholders' Equity - Common Stock Dividends and Reconciliation of Outstanding Common Shares (Details)", "role": "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails", "shortName": "Stockholders' Equity - Common Stock Dividends and Reconciliation of Outstanding Common Shares (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DividendsDeclaredTableTextBlock", "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember_MK8alGHPVkKNS9687RbozQ", "decimals": "INF", "first": true, "lang": null, "name": "us-gaap:CommonStockDividendsPerShareDeclared", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_USD_shares_CIpRh538OUyDxoUsVt6tLg", "xsiNil": "false" } }, "R125": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfOtherComprehensiveIncomeLossTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:OtherComprehensiveIncomeLossBeforeTax", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41302 - Disclosure - Stockholders' Equity - Other Comprehensive Income (Loss) (Details)", "role": "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "shortName": "Stockholders' Equity - Other Comprehensive Income (Loss) (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfOtherComprehensiveIncomeLossTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:OtherComprehensiveIncomeLossBeforeTax", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R126": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:StockholdersEquity", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41303 - Disclosure - Stockholders' Equity - AOCI and Noncontrolling Interest (Details)", "role": "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "shortName": "Stockholders' Equity - AOCI and Noncontrolling Interest (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:RedeemableNoncontrollingInterestTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "us-gaap:NetIncomeLossAttributableToRedeemableNoncontrollingInterest", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R127": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_dei_LegalEntityAxis_pfg_SubsidiariesPrincipalLifeInsuranceCompanyMember_edOKurRR70Ozk0eecgaB1g", "decimals": "2", "first": true, "lang": null, "name": "pfg:DividendRestrictionPercentageOfPolicyholdersSurplus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41304 - Disclosure - Stockholders' Equity - Dividend Limitations (Details)", "role": "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails", "shortName": "Stockholders' Equity - Dividend Limitations (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_dei_LegalEntityAxis_pfg_SubsidiariesPrincipalLifeInsuranceCompanyMember_edOKurRR70Ozk0eecgaB1g", "decimals": "2", "first": true, "lang": null, "name": "pfg:DividendRestrictionPercentageOfPolicyholdersSurplus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R128": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41401 - Disclosure - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "shortName": "Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "2", "lang": null, "name": "pfg:FixedMaturitySecuritiesLevel3ValuedUsingInternalPricingModels", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R129": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "pfg:ScheduleOfFairValueAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_Sf1Vm4bjDEOM_nPgFwZwgg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41402 - Disclosure - Fair Value Measurements - Changes in Level 3 Fair Value Measurements (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "shortName": "Fair Value Measurements - Changes in Level 3 Fair Value Measurements (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_1A9LpF10XkaRawR-X4JroQ", "decimals": "-5", "lang": null, "name": "us-gaap:FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R13": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ClosedBlockDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10601 - Disclosure - Closed Block", "role": "http://principal.com/role/DisclosureClosedBlock", "shortName": "Closed Block", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ClosedBlockDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R130": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:FairValueTransfersTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_FairValueByAssetClassAxis_us-gaap_DebtSecuritiesMember_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_us-gaap_InvestmentSecondaryCategorizationAxis_us-gaap_AvailableforsaleSecuritiesMember_aFbx0Ij_bUm1H5ZXhOe-tQ", "decimals": "-5", "first": true, "lang": null, "name": "pfg:FairValueAssetsLevel2ToLevel1TransfersAmountDuration", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41403 - Disclosure - Fair Value Measurements - Transfers (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "shortName": "Fair Value Measurements - Transfers (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:FairValueTransfersTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_FairValueByAssetClassAxis_us-gaap_DebtSecuritiesMember_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_us-gaap_InvestmentSecondaryCategorizationAxis_us-gaap_AvailableforsaleSecuritiesMember_aFbx0Ij_bUm1H5ZXhOe-tQ", "decimals": "-5", "first": true, "lang": null, "name": "pfg:FairValueAssetsLevel2ToLevel1TransfersAmountDuration", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R131": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_1HE65Nem0Uq1_tnWweXq-Q", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AssetsFairValueDisclosure", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41404 - Disclosure - Fair Value Measurements - Quantitative Information for Level 3 Measurements (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "shortName": "Fair Value Measurements - Quantitative Information for Level 3 Measurements (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:QuantitativeInformationLevel3FairValueMeasurementsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_FairValueByFairValueHierarchyLevelAxis_us-gaap_FairValueInputsLevel3Member_us-gaap_FairValueByLiabilityClassAxis_pfg_InvestmentAndUniversalLifeContractsMember_us-gaap_FairValueByMeasurementFrequencyAxis_us-gaap_FairValueMeasurementsRecurringMember_-uNx4hTa5kGpVvE5NV60LQ", "decimals": "-5", "lang": null, "name": "us-gaap:LiabilitiesFairValueDisclosure", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R132": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:FairValueOptionQuantitativeDisclosuresTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_FinancialInstrumentAxis_pfg_CommercialMortgageLoansOfConsolidatedVariableInterestEntitiesMember_PokIKdEbR06-wb4gddDTFw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41405 - Disclosure - Fair Value Measurements - Fair Value Option on Consolidated VIEs and Equity Method Investments (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails", "shortName": "Fair Value Measurements - Fair Value Option on Consolidated VIEs and Equity Method Investments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:FairValueOptionQuantitativeDisclosuresTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_FinancialInstrumentAxis_pfg_CommercialMortgageLoansOfConsolidatedVariableInterestEntitiesMember_PokIKdEbR06-wb4gddDTFw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R133": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:MortgageLoansOnRealEstateCommercialAndConsumerNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41406 - Disclosure - Fair Value Measurements - Financial Instruments Not Reported at Fair Value (Details)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "shortName": "Fair Value Measurements - Financial Instruments Not Reported at Fair Value (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:FinancialInstrumentsNotReportedAtValueTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_FairValueByMeasurementBasisAxis_us-gaap_CarryingReportedAmountFairValueDisclosureMember_8DKGsfuq4UGklHCFix2UHw", "decimals": "-5", "lang": null, "name": "us-gaap:MortgageLoansOnRealEstateCommercialAndConsumerNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R134": { "firstAnchor": { "ancestors": [ "p", "pfg:StatutoryInsuranceFinancialInformationDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:StatutoryAccountingPracticesPrescribedPracticeAmount", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41501 - Disclosure - Statutory Insurance Financial Information (Details)", "role": "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails", "shortName": "Statutory Insurance Financial Information (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "pfg:StatutoryInsuranceFinancialInformationDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:StatutoryAccountingPracticesPrescribedPracticeAmount", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R135": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:Assets", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41601 - Disclosure - Segment Information - Reconciliation of Segment Assets to Consolidated (Details)", "role": "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "shortName": "Segment Information - Reconciliation of Segment Assets to Consolidated (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_StatementBusinessSegmentsAxis_pfg_SegmentRetirementAndIncomeSolutionsMember_zH6cwwnkw0-1_yndZm2UKg", "decimals": "-5", "lang": null, "name": "us-gaap:Assets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R136": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:SegmentReportingInformationNetRealizedCapitalGainsLosses", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41602 - Disclosure - Segment Information - Reconciliation of Segment Operating Revenues and Earnings to Consolidated (Details)", "role": "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails", "shortName": "Segment Information - Reconciliation of Segment Operating Revenues and Earnings to Consolidated (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "td", "tr", "table", "pfg:ScheduleOfReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_StatementBusinessSegmentsAxis_pfg_SegmentRetirementAndIncomeSolutionsMember_yDbV6cp70UqfwKoil47T7w", "decimals": "-5", "lang": null, "name": "pfg:InterSegmentRevenue", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R137": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:GainLossOnInvestments", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41603 - Disclosure - Segment Information - Net Realized Capital Gains (Losses) (Details)", "role": "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails", "shortName": "Segment Information - Net Realized Capital Gains (Losses) (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "pfg:DerivativeAndHedgingRelatedAdjustments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R138": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:SegmentIncomeTaxExpenseBenefit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41604 - Disclosure - Segment Information - Income Tax Expense by Segment (Details)", "role": "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "shortName": "Segment Information - Income Tax Expense by Segment (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:SegmentIncomeTaxExpenseBenefit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R139": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ReconciliationOfDepreciationAndAmortizationExpenseFromSegmentsToConsolidatedTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DepreciationAndAmortization", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41605 - Disclosure - Segment Information - Depreciation and Amortization Expense by Segment (Details)", "role": "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "shortName": "Segment Information - Depreciation and Amortization Expense by Segment (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ReconciliationOfDepreciationAndAmortizationExpenseFromSegmentsToConsolidatedTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DepreciationAndAmortization", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R14": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DeferredAcquisitionCostTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10701 - Disclosure - Deferred Acquisition Costs", "role": "http://principal.com/role/DisclosureDeferredAcquisitionCosts", "shortName": "Deferred Acquisition Costs", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DeferredAcquisitionCostTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R140": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41701 - Disclosure - Revenues from Contracts with Customers - Disaggregation by Segment (Details)", "role": "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "shortName": "Revenues from Contracts with Customers - Disaggregation by Segment (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DisaggregationOfRevenueTableTextBlock", "us-gaap:RevenueFromContractWithCustomerTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_srt_ConsolidationItemsAxis_us-gaap_MaterialReconcilingItemsMember_JZsazbCuV0Sy9wrHQrZFtg", "decimals": "-5", "lang": null, "name": "pfg:FeesAndOtherRevenuesNotWithinScopeOfRevenueRecognitionGuidance", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R141": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41702 - Disclosure - Revenues from Contracts with Customers - Disaggregation within Segments (Details)", "role": "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "shortName": "Revenues from Contracts with Customers - Disaggregation within Segments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DisaggregationOfRevenueTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_srt_ConsolidationItemsAxis_us-gaap_OperatingSegmentsMember_us-gaap_StatementBusinessSegmentsAxis_pfg_SegmentRetirementAndIncomeSolutionsMember_us-gaap_SubsegmentsAxis_pfg_SubsegmentRetirementAndIncomeSolutionsFeeMember_NnFpQXGYmUu5gsCo6aRRGA", "decimals": "-5", "lang": null, "name": "us-gaap:PremiumsEarnedNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R142": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-6", "first": true, "lang": null, "name": "us-gaap:CapitalizedContractCostNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41703 - Disclosure - Revenues from Contracts with Customers - Contract Costs (Details)", "role": "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails", "shortName": "Revenues from Contracts with Customers - Contract Costs (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-6", "first": true, "lang": null, "name": "us-gaap:CapitalizedContractCostNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R143": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_PlanNameAxis_pfg_StockBasedCompensationPlansMember_9Tuo-x-nzkKu84sb-5v09A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41801 - Disclosure - Stock-Based Compensation Plans - Stock-Based Awards (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails", "shortName": "Stock-Based Compensation Plans - Stock-Based Awards (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_PlanNameAxis_pfg_StockBasedCompensationPlansMember_9Tuo-x-nzkKu84sb-5v09A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R144": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_W6ErOs72zU2YcYwsdJ3UKQ", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber", "reportCount": 1, "unitRef": "Unit_Standard_shares_UgnKE16LEUiVNZpRmYQFcA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41802 - Disclosure - Stock-Based Compensation Plans - Nonqualified Stock Options, Activity (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "shortName": "Stock-Based Compensation Plans - Nonqualified Stock Options, Activity (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_UygVm-x4vkOezW-v7tSLCg", "decimals": "-5", "lang": null, "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_shares_UgnKE16LEUiVNZpRmYQFcA", "xsiNil": "false" } }, "R145": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_Pb2-Tcs7s0O44SC72AIyXQ", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber", "reportCount": 1, "unitRef": "Unit_Standard_shares_UgnKE16LEUiVNZpRmYQFcA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41803 - Disclosure - Stock-Based Compensation Plans - Nonqualified Stock Options, Range of Exercise Prices (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails", "shortName": "Stock-Based Compensation Plans - Nonqualified Stock Options, Range of Exercise Prices (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_UygVm-x4vkOezW-v7tSLCg", "decimals": null, "lang": "en-US", "name": "us-gaap:SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R146": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_UygVm-x4vkOezW-v7tSLCg", "decimals": "3", "first": true, "lang": null, "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41804 - Disclosure - Stock-Based Compensation Plans - Nonqualified Stock Options, Assumptions and Other Disclosures (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "shortName": "Stock-Based Compensation Plans - Nonqualified Stock Options, Assumptions and Other Disclosures (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_EmployeeStockOptionMember_UygVm-x4vkOezW-v7tSLCg", "decimals": "3", "first": true, "lang": null, "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R147": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_PerformanceSharesMember_9Jh7KMamJE6ekSIcZ9inAw", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41805 - Disclosure - Stock-Based Compensation Plans - Performance Share Awards and Restricted Stock Units (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "shortName": "Stock-Based Compensation Plans - Performance Share Awards and Restricted Stock Units (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_AwardTypeAxis_us-gaap_PerformanceSharesMember_9Jh7KMamJE6ekSIcZ9inAw", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R148": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_PlanNameAxis_pfg_EmployeeStockPurchasePlanMember_KLCiBp5Qj02O3uWqjiYoDw", "decimals": "INF", "first": true, "lang": null, "name": "pfg:MaximumValueOfSharesAvailableForPurchasePerYear", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41806 - Disclosure - Stock-Based Compensation Plans - Employee Stock Purchase Plan (Details)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails", "shortName": "Stock-Based Compensation Plans - Employee Stock Purchase Plan (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_PlanNameAxis_pfg_EmployeeStockPurchasePlanMember_KLCiBp5Qj02O3uWqjiYoDw", "decimals": "INF", "first": true, "lang": null, "name": "pfg:MaximumValueOfSharesAvailableForPurchasePerYear", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R149": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock", "us-gaap:QuarterlyFinancialInformationTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_10_1_2019_To_12_31_2019_favHvraZeEyk1mJXvbNNJA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "41901 - Disclosure - Earnings Per Common Share (Details)", "role": "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "shortName": "Earnings Per Common Share (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock", "us-gaap:EarningsPerShareTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R15": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:InsuranceLiabilitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10801 - Disclosure - Insurance Liabilities", "role": "http://principal.com/role/DisclosureInsuranceLiabilities", "shortName": "Insurance Liabilities", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:InsuranceLiabilitiesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R150": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock", "us-gaap:QuarterlyFinancialInformationTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_10_1_2019_To_12_31_2019_favHvraZeEyk1mJXvbNNJA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:Revenues", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42001 - Disclosure - Quarterly Results of Operations (Unaudited) (Details)", "role": "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "shortName": "Quarterly Results of Operations (Unaudited) (Details)", "subGroupType": "details", "uniqueAnchor": null }, "R151": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42101 - Disclosure - Condensed Consolidating Financial Information - Guarantor, Statements of Financial Position (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "shortName": "Condensed Consolidating Financial Information - Guarantor, Statements of Financial Position (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCondensedFinancialStatementsNotesGuarantorTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_pfg_ParentAndSubsidiariesNotesGuarantorAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_up1fMjLHAEyswhN6I-BXRg", "decimals": "-5", "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R152": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:PremiumsEarnedNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42102 - Disclosure - Condensed Consolidating Financial Information - Guarantor, Statements of Operations (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "shortName": "Condensed Consolidating Financial Information - Guarantor, Statements of Operations (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_pfg_ParentAndSubsidiariesNotesGuarantorAxis_pfg_SubsidiariesPrincipalLifeInsuranceCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_PiWkFMM_aU6r-K8w6MZUjg", "decimals": "-5", "lang": null, "name": "us-gaap:PremiumsEarnedNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R153": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:NetCashProvidedByUsedInOperatingActivities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42103 - Disclosure - Condensed Consolidating Financial Information - Guarantor, Statements of Cash Flows (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "shortName": "Condensed Consolidating Financial Information - Guarantor, Statements of Cash Flows (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_pfg_ParentAndSubsidiariesNotesGuarantorAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_X_sMD0PLfECWf6R0_U9ofw", "decimals": "-5", "lang": null, "name": "us-gaap:NetCashProvidedByUsedInOperatingActivities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R154": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42104 - Disclosure - Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Financial Position (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "shortName": "Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Financial Position (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCondensedFinancialStatementsShelfRegistrationDebtGuarantorTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_pfg_ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_bRs1fRtCqUeYMwaGIdVKGA", "decimals": "-5", "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R155": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:PremiumsEarnedNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42105 - Disclosure - Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Operations (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "shortName": "Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Operations (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2017_To_12_31_2017_pfg_ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_rfsP0R4Xw0i4tRooLZFPiA", "decimals": "-5", "lang": null, "name": "pfg:InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R156": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:NetCashProvidedByUsedInOperatingActivities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42106 - Disclosure - Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Cash Flows (Details)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "shortName": "Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Cash Flows (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_pfg_ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_0dF3v3WQNESpFMS5hgMTqg", "decimals": "-5", "lang": null, "name": "us-gaap:NetCashProvidedByUsedInOperatingActivities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R157": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "srt:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42201 - Disclosure - Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details)", "role": "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "shortName": "Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "srt:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R158": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42301 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position (Details)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position (Details)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_3youpqA2kECKqmFqmRtZWQ", "decimals": "-5", "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R159": { "firstAnchor": { "ancestors": [ "us-gaap:CommonStockParOrStatedValuePerShare", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:CommonStockParOrStatedValuePerShare", "reportCount": 1, "unitRef": "Unit_Divide_USD_shares_CIpRh538OUyDxoUsVt6tLg", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42302 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position - Parenthetical (Details)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position - Parenthetical (Details)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "us-gaap:CommonStockParOrStatedValuePerShare", "p", "td", "tr", "table", "us-gaap:CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_3youpqA2kECKqmFqmRtZWQ", "decimals": "INF", "lang": null, "name": "us-gaap:CommonStockParOrStatedValuePerShare", "reportCount": 1, "unique": true, "unitRef": "Unit_Divide_USD_shares_CIpRh538OUyDxoUsVt6tLg", "xsiNil": "false" } }, "R16": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DebtDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10901 - Disclosure - Debt", "role": "http://principal.com/role/DisclosureDebt", "shortName": "Debt", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DebtDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R160": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42303 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Operations (Details)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Operations (Details)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "span", "p", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2017_To_12_31_2017_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_ySDTes194kaju9xrM4pudQ", "decimals": "-5", "lang": null, "name": "pfg:InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R161": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock", "us-gaap:QuarterlyFinancialInformationTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_10_1_2019_To_12_31_2019_favHvraZeEyk1mJXvbNNJA", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42304 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Cash Flows (Details)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Cash Flows (Details)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_ts-oHz4Yd0W-QU5_sBcddQ", "decimals": "-5", "lang": null, "name": "us-gaap:ProfitLoss", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R162": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_ts-oHz4Yd0W-QU5_sBcddQ", "decimals": "-5", "first": true, "lang": null, "name": "pfg:DividendsReceivedFromContributionsToUnconsolidatedEntities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42305 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) - Financial Statement Footnotes (Details)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only) - Financial Statement Footnotes (Details)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ConsolidatedEntitiesAxis_srt_ParentCompanyMember_srt_ConsolidationItemsAxis_srt_ReportableLegalEntitiesMember_us-gaap_RetirementPlanTaxStatusAxis_us-gaap_NonqualifiedPlanMember_q2cpa4LzaU2sVcPEn_uyaA", "decimals": "-5", "lang": null, "name": "pfg:PlanAssetsHeldInRabbiTrusts", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R163": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DeferredPolicyAcquisitionCosts", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42401 - Disclosure - Schedule III - Supplementary Insurance Information (Details)", "role": "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "shortName": "Schedule III - Supplementary Insurance Information (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "srt:SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "pfg:ContractholderAndOtherPolicyholderFunds", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R164": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "srt:SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "srt:LifeInsuranceInForceGross", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "42501 - Disclosure - Schedule IV - Reinsurance (Details)", "role": "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails", "shortName": "Schedule IV - Reinsurance (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "srt:SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "srt:LifeInsuranceInForceGross", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R17": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:IncomeTaxDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11001 - Disclosure - Income Taxes", "role": "http://principal.com/role/DisclosureIncomeTaxes", "shortName": "Income Taxes", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:IncomeTaxDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R18": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11101 - Disclosure - Employee and Agent Benefits", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefits", "shortName": "Employee and Agent Benefits", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R19": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11201 - Disclosure - Contingencies, Guarantees, Indemnifications and Leases", "role": "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeases", "shortName": "Contingencies, Guarantees, Indemnifications and Leases", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R2": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00100 - Statement - Consolidated Statements of Financial Position", "role": "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "shortName": "Consolidated Statements of Financial Position", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:Investments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R20": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11301 - Disclosure - Stockholders' Equity", "role": "http://principal.com/role/DisclosureStockholdersEquity", "shortName": "Stockholders' Equity", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R21": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:FairValueDisclosuresTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11401 - Disclosure - Fair Value Measurements", "role": "http://principal.com/role/DisclosureFairValueMeasurements", "shortName": "Fair Value Measurements", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:FairValueDisclosuresTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R22": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:StatutoryInsuranceFinancialInformationDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11501 - Disclosure - Statutory Insurance Financial Information", "role": "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformation", "shortName": "Statutory Insurance Financial Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:StatutoryInsuranceFinancialInformationDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R23": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:SegmentReportingDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11601 - Disclosure - Segment Information", "role": "http://principal.com/role/DisclosureSegmentInformation", "shortName": "Segment Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:SegmentReportingDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R24": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:RevenueFromContractWithCustomerTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11701 - Disclosure - Revenues from Contracts with Customers", "role": "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomers", "shortName": "Revenues from Contracts with Customers", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:RevenueFromContractWithCustomerTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R25": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11801 - Disclosure - Stock-Based Compensation Plans", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlans", "shortName": "Stock-Based Compensation Plans", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R26": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:EarningsPerShareTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "11901 - Disclosure - Earnings Per Common Share", "role": "http://principal.com/role/DisclosureEarningsPerCommonShare", "shortName": "Earnings Per Common Share", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:EarningsPerShareTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R27": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:QuarterlyFinancialInformationTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12001 - Disclosure - Quarterly Results of Operations (Unaudited)", "role": "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnaudited", "shortName": "Quarterly Results of Operations (Unaudited)", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:QuarterlyFinancialInformationTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R28": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:CondensedFinancialStatementsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12101 - Disclosure - Condensed Consolidating Financial Information", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformation", "shortName": "Condensed Consolidating Financial Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:CondensedFinancialStatementsTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R29": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12201 - Disclosure - Schedule I - Summary of Investments - Other Than Investments in Related Parties", "role": "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedParties", "shortName": "Schedule I - Summary of Investments - Other Than Investments in Related Parties", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R3": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00105 - Statement - Consolidated Statements of Financial Position (Parenthetical)", "role": "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical", "shortName": "Consolidated Statements of Financial Position (Parenthetical)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "pfg:OtherInvestmentsFairValueOption", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R30": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12301 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only)", "role": "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnly", "shortName": "Schedule II - Condensed Financial Information of Registrant (Parent Only)", "subGroupType": "parenthetical", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R31": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12401 - Disclosure - Schedule III - Supplementary Insurance Information", "role": "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformation", "shortName": "Schedule III - Supplementary Insurance Information", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R32": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "12501 - Disclosure - Schedule IV - Reinsurance", "role": "http://principal.com/role/DisclosureScheduleIvReinsurance", "shortName": "Schedule IV - Reinsurance", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "srt:SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R33": { "firstAnchor": { "ancestors": [ "us-gaap:OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:BasisOfAccountingPolicyPolicyTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "20102 - Disclosure - Nature of Operations and Significant Accounting Policies (Policies)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies", "shortName": "Nature of Operations and Significant Accounting Policies (Policies)", "subGroupType": "policies", "uniqueAnchor": { "ancestors": [ "us-gaap:OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:BasisOfAccountingPolicyPolicyTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R34": { "firstAnchor": { "ancestors": [ "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfEffectOfReinsuranceOnPremiumsAndOtherConsiderationAndPolicyAndContractBenefitsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30103 - Disclosure - Nature of Operations and Significant Accounting Policies (Tables)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesTables", "shortName": "Nature of Operations and Significant Accounting Policies (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfEffectOfReinsuranceOnPremiumsAndOtherConsiderationAndPolicyAndContractBenefitsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R35": { "firstAnchor": { "ancestors": [ "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfGoodwillTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30203 - Disclosure - Goodwill and Other Intangible Assets (Tables)", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables", "shortName": "Goodwill and Other Intangible Assets (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfGoodwillTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R36": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30303 - Disclosure - Variable Interest Entities (Tables)", "role": "http://principal.com/role/DisclosureVariableInterestEntitiesTables", "shortName": "Variable Interest Entities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R37": { "firstAnchor": { "ancestors": [ "pfg:InvestmentsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30403 - Disclosure - Investments (Tables)", "role": "http://principal.com/role/DisclosureInvestmentsTables", "shortName": "Investments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "pfg:InvestmentsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R38": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30503 - Disclosure - Derivative Financial Instruments (Tables)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables", "shortName": "Derivative Financial Instruments (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R39": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfClosedBlockAssetsAndLiabilities", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30603 - Disclosure - Closed Block (Tables)", "role": "http://principal.com/role/DisclosureClosedBlockTables", "shortName": "Closed Block (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfClosedBlockAssetsAndLiabilities", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R4": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:PremiumsEarnedNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00200 - Statement - Consolidated Statements of Operations", "role": "http://principal.com/role/StatementConsolidatedStatementsOfOperations", "shortName": "Consolidated Statements of Operations", "subGroupType": "", "uniqueAnchor": null }, "R40": { "firstAnchor": { "ancestors": [ "pfg:DeferredAcquisitionCostTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfDeferredAcquisitionCostsDisclosureTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30703 - Disclosure - Deferred Acquisition Costs (Tables)", "role": "http://principal.com/role/DisclosureDeferredAcquisitionCostsTables", "shortName": "Deferred Acquisition Costs (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "pfg:DeferredAcquisitionCostTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfDeferredAcquisitionCostsDisclosureTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R41": { "firstAnchor": { "ancestors": [ "pfg:InsuranceLiabilitiesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfContractholderFundsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30803 - Disclosure - Insurance Liabilities (Tables)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesTables", "shortName": "Insurance Liabilities (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "pfg:InsuranceLiabilitiesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfContractholderFundsTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R42": { "firstAnchor": { "ancestors": [ "us-gaap:DebtDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfShortTermDebtTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "30903 - Disclosure - Debt (Tables)", "role": "http://principal.com/role/DisclosureDebtTables", "shortName": "Debt (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:DebtDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfShortTermDebtTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R43": { "firstAnchor": { "ancestors": [ "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31003 - Disclosure - Income Taxes (Tables)", "role": "http://principal.com/role/DisclosureIncomeTaxesTables", "shortName": "Income Taxes (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:IncomeTaxDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R44": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31103 - Disclosure - Employee and Agent Benefits (Tables)", "role": "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables", "shortName": "Employee and Agent Benefits (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfNetFundedStatusTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R45": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:LeaseBalanceSheetDisclosureTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31203 - Disclosure - Contingencies, Guarantees, Indemnifications and Leases (Tables)", "role": "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesTables", "shortName": "Contingencies, Guarantees, Indemnifications and Leases (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:LeaseBalanceSheetDisclosureTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R46": { "firstAnchor": { "ancestors": [ "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DividendsDeclaredTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31303 - Disclosure - Stockholders' Equity (Tables)", "role": "http://principal.com/role/DisclosureStockholdersEquityTables", "shortName": "Stockholders' Equity (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:StockholdersEquityNoteDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DividendsDeclaredTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R47": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31403 - Disclosure - Fair Value Measurements (Tables)", "role": "http://principal.com/role/DisclosureFairValueMeasurementsTables", "shortName": "Fair Value Measurements (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R48": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfStatutoryAccountingPracticesStatutoryNetIncomeAndSurplusTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31503 - Disclosure - Statutory Insurance Financial Information (Tables)", "role": "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationTables", "shortName": "Statutory Insurance Financial Information (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfStatutoryAccountingPracticesStatutoryNetIncomeAndSurplusTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R49": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31603 - Disclosure - Segment Information (Tables)", "role": "http://principal.com/role/DisclosureSegmentInformationTables", "shortName": "Segment Information (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R5": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00300 - Statement - Consolidated Statements of Comprehensive Income", "role": "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome", "shortName": "Consolidated Statements of Comprehensive Income", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "pfg:OtherComprehensiveIncomeAvailableForSaleSecuritiesPeriodIncreaseDecreaseNetOfTax", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R50": { "firstAnchor": { "ancestors": [ "us-gaap:RevenueFromContractWithCustomerTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DisaggregationOfRevenueTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31703 - Disclosure - Revenues from Contracts with Customers (Tables)", "role": "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "shortName": "Revenues from Contracts with Customers (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:RevenueFromContractWithCustomerTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:DisaggregationOfRevenueTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R51": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31803 - Disclosure - Stock-Based Compensation Plans (Tables)", "role": "http://principal.com/role/DisclosureStockBasedCompensationPlansTables", "shortName": "Stock-Based Compensation Plans (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R52": { "firstAnchor": { "ancestors": [ "us-gaap:EarningsPerShareTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "31903 - Disclosure - Earnings Per Common Share (Tables)", "role": "http://principal.com/role/DisclosureEarningsPerCommonShareTables", "shortName": "Earnings Per Common Share (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:EarningsPerShareTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R53": { "firstAnchor": { "ancestors": [ "us-gaap:QuarterlyFinancialInformationTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32003 - Disclosure - Quarterly Results of Operations (Unaudited) (Tables)", "role": "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedTables", "shortName": "Quarterly Results of Operations (Unaudited) (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "us-gaap:QuarterlyFinancialInformationTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R54": { "firstAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfCondensedFinancialStatementsNotesGuarantorTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "32103 - Disclosure - Condensed Consolidating Financial Information (Tables)", "role": "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationTables", "shortName": "Condensed Consolidating Financial Information (Tables)", "subGroupType": "tables", "uniqueAnchor": { "ancestors": [ "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:ScheduleOfCondensedFinancialStatementsNotesGuarantorTableTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R55": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:Assets", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40101 - Disclosure - Nature of Operations and Significant Accounting Policies - Recent Accounting Pronouncements (Details)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "shortName": "Nature of Operations and Significant Accounting Policies - Recent Accounting Pronouncements (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_1_1_2019_jk2xw1wlUE6TwFCg4U1m_Q", "decimals": null, "lang": "en-US", "name": "us-gaap:LeasePracticalExpedientsPackage", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R56": { "firstAnchor": { "ancestors": [ "p", "us-gaap:CashAndCashEquivalentsPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:CashAndCashEquivalentsMaximumMaturityPeriod", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40102 - Disclosure - Nature of Operations and Significant Accounting Policies - Cash and Cash Equivalents, Investments (Details)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesCashAndCashEquivalentsInvestmentsDetails", "shortName": "Nature of Operations and Significant Accounting Policies - Cash and Cash Equivalents, Investments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "us-gaap:CashAndCashEquivalentsPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:CashAndCashEquivalentsMaximumMaturityPeriod", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R57": { "firstAnchor": { "ancestors": [ "p", "pfg:ContractholderAndPolicyholderLiabilitiesPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_SubsegmentsAxis_pfg_SubsegmentIndividualLifeInsuranceMember_b-q0S_okr0eG2eDTxJGM4A", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40103 - Disclosure - Nature of Operations and Significant Accounting Policies - Contractholder and Policyholder Liabilities (Details)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails", "shortName": "Nature of Operations and Significant Accounting Policies - Contractholder and Policyholder Liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "pfg:ContractholderAndPolicyholderLiabilitiesPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_SubsegmentsAxis_pfg_SubsegmentIndividualLifeInsuranceMember_b-q0S_okr0eG2eDTxJGM4A", "decimals": "2", "first": true, "lang": null, "name": "us-gaap:ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } }, "R58": { "firstAnchor": { "ancestors": [ "p", "us-gaap:DebtPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:LongTermDebtMinimumMaturityPeriod", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40104 - Disclosure - Nature of Operations and Significant Accounting Policies - Other Various Policies (Details)", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "shortName": "Nature of Operations and Significant Accounting Policies - Other Various Policies (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "us-gaap:DebtPolicyTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:LongTermDebtMinimumMaturityPeriod", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R59": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:Goodwill", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40201 - Disclosure - Goodwill and Other Intangible Assets - Changes in Goodwill (Details)", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "shortName": "Goodwill and Other Intangible Assets - Changes in Goodwill (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfGoodwillTextBlock", "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2018_To_12_31_2018_OU8IATdaQEGqX9NtKGuISw", "decimals": "-5", "lang": null, "name": "us-gaap:GoodwillWrittenOffRelatedToSaleOfBusinessUnit", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R6": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember_BFQqabsywEmsH7glJ3Jwtw", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00400 - Statement - Consolidated Statements of Stockholders' Equity", "role": "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity", "shortName": "Consolidated Statements of Stockholders' Equity", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember_BFQqabsywEmsH7glJ3Jwtw", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R60": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfGoodwillTextBlock", "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:GoodwillAcquiredDuringPeriod", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40202 - Disclosure - Goodwill and Other Intangible Assets - Goodwill Acquired (Details)", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails", "shortName": "Goodwill and Other Intangible Assets - Goodwill Acquired (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_7_1_2019_To_7_1_2019_us-gaap_BusinessAcquisitionAxis_pfg_InstitutionalRetirementAndTrustBusinessOfWellsFargoBankMember_hZs-t76SOUWPAr-9NJ_wpg", "decimals": "-8", "lang": null, "name": "us-gaap:PaymentsToAcquireBusinessesGross", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R61": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40203 - Disclosure - Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets (Details)", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails", "shortName": "Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "pfg:FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R62": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40204 - Disclosure - Goodwill and Other Intangible Assets - Indefinite-Lived Intangible Assets (Details)", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails", "shortName": "Goodwill and Other Intangible Assets - Indefinite-Lived Intangible Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R63": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:Assets", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40301 - Disclosure - Variable Interest Entities - Consolidated VIEs (Details)", "role": "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "shortName": "Variable Interest Entities - Consolidated VIEs (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ConsolidatedEntitiesAxis_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_ytisGKUTFkiAed2K3mWkTA", "decimals": "-5", "lang": null, "name": "us-gaap:Assets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R64": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-8", "first": true, "lang": null, "name": "pfg:TotalAssetsUnconsolidatedMoneyMarketMutualFund", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40302 - Disclosure - Variable Interest Entities - Unconsolidated VIEs (Details)", "role": "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails", "shortName": "Variable Interest Entities - Unconsolidated VIEs (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-8", "first": true, "lang": null, "name": "pfg:TotalAssetsUnconsolidatedMoneyMarketMutualFund", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R65": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock", "pfg:InvestmentsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40401 - Disclosure - Investments - Fixed Maturities and Equity Securities (Details)", "role": "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "shortName": "Investments - Fixed Maturities and Equity Securities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock", "pfg:InvestmentsDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R66": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40402 - Disclosure - Investments - Amortization by Expected Maturity (Details)", "role": "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails", "shortName": "Investments - Amortization by Expected Maturity (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R67": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:InvestmentIncomeTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossInvestmentIncomeLoss", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40403 - Disclosure - Investments - Net Investment Income (Details)", "role": "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "shortName": "Investments - Net Investment Income (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:InvestmentIncomeTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossInvestmentIncomeLoss", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R68": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:GainLossOnInvestmentsStatementOfOperationsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtSecuritiesAvailableForSaleRealizedGain", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40404 - Disclosure - Investments - Net Realized Capital Gains and Losses (Details)", "role": "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "shortName": "Investments - Net Realized Capital Gains and Losses (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:GainLossOnInvestmentsStatementOfOperationsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtSecuritiesAvailableForSaleRealizedGain", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R69": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:OtherThanTemporaryImpairmentLossesRecoveriesInvestmentsAvailableForSaleSecurities", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40405 - Disclosure - Investments - Other-Than-Temporary Impairments (Details)", "role": "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "shortName": "Investments - Other-Than-Temporary Impairments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfOtherThanTemporaryImpairmentLossesNetOfRecoveriesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_InvestmentTypeAxis_us-gaap_DebtSecuritiesMember_VezWM2F7z0G_VcoXSRvSrg", "decimals": "-5", "lang": null, "name": "pfg:OtherThanTemporaryImpairmentLossesRecoveriesInvestmentsAvailableForSaleSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R7": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ProfitLoss", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "statement", "isDefault": "false", "longName": "00500 - Statement - Consolidated Statements of Cash Flows", "role": "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows", "shortName": "Consolidated Statements of Cash Flows", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "us-gaap:DepreciationAmortizationAndAccretionNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R70": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40406 - Disclosure - Investments - Accumulated Credit Losses for Fixed Maturities with Bifurcated Credit Losses (Details)", "role": "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails", "shortName": "Investments - Accumulated Credit Losses for Fixed Maturities with Bifurcated Credit Losses (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_QrVbGqN2iEGfyKBqKo9U6A", "decimals": "-5", "lang": null, "name": "us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R71": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40407 - Disclosure - Investments - Gross Unrealized Losses for Fixed Maturities (Details)", "role": "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "shortName": "Investments - Gross Unrealized Losses for Fixed Maturities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R72": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40408 - Disclosure - Investments - Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Details)", "role": "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails", "shortName": "Investments - Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R73": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:NotesReceivableGross", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40409 - Disclosure - Investments - Mortgage Loans (Details)", "role": "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "shortName": "Investments - Mortgage Loans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:NotesReceivableNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R74": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:NotesReceivableGross", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40410 - Disclosure - Investments - Mortgage Loan Credit Monitoring (Details)", "role": "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "shortName": "Investments - Mortgage Loan Credit Monitoring (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCommercialMortgageLoansCreditQualityIndicatorsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_CreditRatingStandardPoorsAxis_pfg_StandardPoorsAMinusAndAboveRatingMember_srt_MortgageLoansOnRealEstateLoanTypeAxis_us-gaap_CommercialRealEstatePortfolioSegmentMember_x8ozmn5XCEartYRm8rnaHA", "decimals": "-5", "lang": null, "name": "us-gaap:NotesReceivableGross", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R75": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:FinancingReceivableRecordedInvestmentNonaccrualStatus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40411 - Disclosure - Investments - Mortgage Loans, Non-Accrual and Aging (Details)", "role": "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails", "shortName": "Investments - Mortgage Loans, Non-Accrual and Aging (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:FinancingReceivableRecordedInvestmentNonaccrualStatus", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R76": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:FinancingReceivableAllowanceForCreditLosses", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40412 - Disclosure - Investments - Mortgage Loan Valuation Allowance (Details)", "role": "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "shortName": "Investments - Mortgage Loan Valuation Allowance (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "us-gaap:ProvisionForLoanLeaseAndOtherLosses", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R77": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ImpairedFinancingReceivablesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_MortgageLoansOnRealEstateLoanTypeAxis_us-gaap_ResidentialMortgageMember_xM1mDziVEE62MBS3pk6CBQ", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ImpairedFinancingReceivableRecordedInvestment", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40413 - Disclosure - Investments - Impaired Mortgage Loans (Details)", "role": "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "shortName": "Investments - Impaired Mortgage Loans (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ImpairedFinancingReceivablesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_MortgageLoansOnRealEstateLoanTypeAxis_us-gaap_ResidentialMortgageMember_xM1mDziVEE62MBS3pk6CBQ", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ImpairedFinancingReceivableRecordedInvestment", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R78": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:RealEstateDepreciationExpense", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40414 - Disclosure - Investments - Real Estate (Details)", "role": "http://principal.com/role/DisclosureInvestmentsRealEstateDetails", "shortName": "Investments - Real Estate (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "pfg:RealEstateDepreciationExpense", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R79": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:EquityMethodInvestmentSummarizedFinancialInformationAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40415 - Disclosure - Investments - Other Investments (Details)", "role": "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails", "shortName": "Investments - Other Investments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:EquityMethodInvestmentSummarizedFinancialInformationAssets", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R8": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10101 - Disclosure - Nature of Operations and Significant Accounting Policies", "role": "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPolicies", "shortName": "Nature of Operations and Significant Accounting Policies", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R80": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LoansPledgedAsCollateral", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40416 - Disclosure - Investments - Securities Posted as Collateral (Details)", "role": "http://principal.com/role/DisclosureInvestmentsSecuritiesPostedAsCollateralDetails", "shortName": "Investments - Securities Posted as Collateral (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LoansPledgedAsCollateral", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R81": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:OffsettingAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossAmountRecognizedAssetsSubjectToNetting", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40417 - Disclosure - Investments - Balance Sheet Offsetting, Assets (Details)", "role": "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails", "shortName": "Investments - Balance Sheet Offsetting, Assets (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:OffsettingAssetsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossAmountRecognizedAssetsSubjectToNetting", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R82": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:OffsettingLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_pfg_FinancialLiabilityTypeAxis_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_ODPzjeHipku23IsM1rIVKw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossAmountRecognizedLiabilitiesSubjectToNetting", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40418 - Disclosure - Investments - Balance Sheet Offsetting, Liabilities (Details)", "role": "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails", "shortName": "Investments - Balance Sheet Offsetting, Liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:OffsettingLiabilitiesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_pfg_FinancialLiabilityTypeAxis_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_ODPzjeHipku23IsM1rIVKw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:GrossAmountRecognizedLiabilitiesSubjectToNetting", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R83": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:DerivativeCollateralPledged", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40501 - Disclosure - Derivative Financial Instruments - Notional Amounts and Credit Exposure (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails", "shortName": "Derivative Financial Instruments - Notional Amounts and Credit Exposure (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:DerivativeCollateralPledged", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R84": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40502 - Disclosure - Derivative Financial Instruments - Fair Value of Derivatives (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails", "shortName": "Derivative Financial Instruments - Fair Value of Derivatives (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R85": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DisclosureOfCreditDerivativesTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_CreditDerivativesByContractTypeAxis_us-gaap_CreditDefaultSwapMember_aT1KZNK-iUqBlY-SxJjPWw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:CreditDerivativeSoldNotional", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40503 - Disclosure - Derivative Financial Instruments - Credit Derivatives Sold (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails", "shortName": "Derivative Financial Instruments - Credit Derivatives Sold (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:DisclosureOfCreditDerivativesTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_CreditDerivativesByContractTypeAxis_us-gaap_CreditDefaultSwapMember_aT1KZNK-iUqBlY-SxJjPWw", "decimals": "-5", "first": true, "lang": null, "name": "pfg:CreditDerivativeSoldNotional", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R86": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_BalanceSheetLocationAxis_pfg_FixedMaturitiesSecuritiesAvailableForSaleMember_I2OiDNBejUiHqkgh5uyBgg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:HedgedAssetFairValueHedge", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40504 - Disclosure - Derivative Financial Instruments - Fair Value Hedges (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails", "shortName": "Derivative Financial Instruments - Fair Value Hedges (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_us-gaap_BalanceSheetLocationAxis_pfg_FixedMaturitiesSecuritiesAvailableForSaleMember_I2OiDNBejUiHqkgh5uyBgg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:HedgedAssetFairValueHedge", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R87": { "firstAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:MaximumLengthOfTimeHedgedInCashFlowHedge1", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40505 - Disclosure - Derivative Financial Instruments - Cash Flow Hedges (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "shortName": "Derivative Financial Instruments - Cash Flow Hedges (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:MaximumLengthOfTimeHedgedInCashFlowHedge1", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R88": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:NetInvestmentIncome", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40506 - Disclosure - Derivative Financial Instruments - Effect of Hedges on Consolidated Statements of Operations (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "shortName": "Derivative Financial Instruments - Effect of Hedges on Consolidated Statements of Operations (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfEffectOfDerivativesInFairValueAndCashFlowHedgingRelationshipsAndRelatedHedgedItemsOnConsolidatedStatementOfOperationsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_us-gaap_DerivativeInstrumentRiskAxis_us-gaap_InterestRateContractMember_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_us-gaap_FairValueHedgingMember_us-gaap_IncomeStatementLocationAxis_pfg_NetInvestmentIncomeLossMember_U93bMbIYW0eiiuSA4zl3ag", "decimals": "-5", "lang": null, "name": "us-gaap:ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R89": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40507 - Disclosure - Derivative Financial Instruments - Derivatives Not Designated as Hedging Instruments (Details)", "role": "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "shortName": "Derivative Financial Instruments - Derivatives Not Designated as Hedging Instruments (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R9": { "firstAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "10201 - Disclosure - Goodwill and Other Intangible Assets", "role": "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssets", "shortName": "Goodwill and Other Intangible Assets", "subGroupType": "", "uniqueAnchor": { "ancestors": [ "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": null, "first": true, "lang": "en-US", "name": "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock", "reportCount": 1, "unique": true, "unitRef": null, "xsiNil": "false" } }, "R90": { "firstAnchor": { "ancestors": [ "p", "us-gaap:ClosedBlockDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ClosedBlockLiabilitiesPolicyholderDividendObligation", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40601 - Disclosure - Closed Block - Assets and Liabilities (Details)", "role": "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails", "shortName": "Closed Block - Assets and Liabilities (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ScheduleOfClosedBlockAssetsAndLiabilities", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "us-gaap:ClosedBlockLiabilitiesFuturePolicyBenefitsAndPolicyholderAccountBalances", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R91": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ClosedBlockOperationsNetResultsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ClosedBlockOperationsPremiums", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40602 - Disclosure - Closed Block - Revenues and Expenses (Details)", "role": "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails", "shortName": "Closed Block - Revenues and Expenses (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ClosedBlockOperationsNetResultsTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ClosedBlockOperationsPremiums", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R92": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfClosedBlockAssetsAndLiabilities", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40603 - Disclosure - Closed Block - Change in Maximum Future Earnings (Details)", "role": "http://principal.com/role/DisclosureClosedBlockChangeInMaximumFutureEarningsDetails", "shortName": "Closed Block - Change in Maximum Future Earnings (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "pfg:ScheduleOfChangeInMaximumFutureEarningsOfClosedBlockTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "lang": null, "name": "pfg:ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedCumulativeEffectOfNewAccountingPrinciple", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R93": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:DeferredPolicyAcquisitionCosts", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40701 - Disclosure - Deferred Acquisition Costs (Details)", "role": "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails", "shortName": "Deferred Acquisition Costs (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfDeferredAcquisitionCostsDisclosureTableTextBlock", "pfg:DeferredAcquisitionCostTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_szpVrYq0gkeO3qOE7Jt39A", "decimals": "-5", "lang": null, "name": "us-gaap:DeferredPolicyAcquisitionCostsAdditions", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R94": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfContractholderFundsTableTextBlock", "pfg:InsuranceLiabilitiesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:LiabilityForFuturePolicyBenefitsIndividualAnnuities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40801 - Disclosure - Insurance Liabilities - Components of Contractholder Funds (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails", "shortName": "Insurance Liabilities - Components of Contractholder Funds (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfContractholderFundsTableTextBlock", "pfg:InsuranceLiabilitiesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:LiabilityForFuturePolicyBenefitsIndividualAnnuities", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R95": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "pfg:ScheduleOfContractholderFundsTableTextBlock", "pfg:InsuranceLiabilitiesDisclosureTextBlock", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "pfg:FundingAgreements", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40802 - Disclosure - Insurance Liabilities - Contractholder Funding Agreements (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails", "shortName": "Insurance Liabilities - Contractholder Funding Agreements (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "Duration_1_1_2019_To_12_31_2019_dei_LegalEntityAxis_pfg_PrincipalLifeInsuranceCompanyConsolidatedMember_r8jxAcBjYk6dkklyNFYBWA", "decimals": "INF", "lang": null, "name": "pfg:FundingAgreementsProgramsNumber", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_item_j5ZbdD4KskmT0NnezP59Og", "xsiNil": "false" } }, "R96": { "firstAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2018_aewdgdfHq0qTHR27kDY43A", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:LiabilityForClaimsAndClaimsAdjustmentExpense", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40803 - Disclosure - Insurance Liabilities - Liability for Unpaid Claims (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails", "shortName": "Insurance Liabilities - Liability for Unpaid Claims (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "p", "td", "tr", "table", "us-gaap:ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2016_QrVbGqN2iEGfyKBqKo9U6A", "decimals": "-5", "lang": null, "name": "us-gaap:ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R97": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40804 - Disclosure - Insurance Liabilities - Claims Development Tables (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "shortName": "Insurance Liabilities - Claims Development Tables (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsClaimsDevelopmentTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ProductOrServiceAxis_pfg_LongTermDisabilityGroupLifeWaiverMember_SkrwExC8EEaJJe8JmzFYIw", "decimals": "-5", "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R98": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "first": true, "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "reportCount": 1, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40805 - Disclosure - Insurance Liabilities - Reconciliation of Unpaid Claims to Liability for Unpaid Claims Table (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "shortName": "Insurance Liabilities - Reconciliation of Unpaid Claims to Liability for Unpaid Claims Table (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_U8JTxeK2pUWB6n4HMsKOvg", "decimals": "-5", "lang": null, "name": "pfg:ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustmentsShortDurationInsuranceContracts", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_USD_nKacwRhf9UOD7Z6gzoi7eA", "xsiNil": "false" } }, "R99": { "firstAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ProductOrServiceAxis_pfg_LongTermDisabilityGroupLifeWaiverMember_SkrwExC8EEaJJe8JmzFYIw", "decimals": "3", "first": true, "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" }, "groupType": "disclosure", "isDefault": "false", "longName": "40806 - Disclosure - Insurance Liabilities - Claim Duration and Payout Table (Details)", "role": "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "shortName": "Insurance Liabilities - Claim Duration and Payout Table (Details)", "subGroupType": "details", "uniqueAnchor": { "ancestors": [ "b", "p", "td", "tr", "table", "us-gaap:ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock", "ix:continuation", "div", "div", "body", "html" ], "baseRef": "pfg-20191231x10k0da4e5.htm", "contextRef": "As_Of_12_31_2019_srt_ProductOrServiceAxis_pfg_LongTermDisabilityGroupLifeWaiverMember_SkrwExC8EEaJJe8JmzFYIw", "decimals": "3", "first": true, "lang": null, "name": "us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne", "reportCount": 1, "unique": true, "unitRef": "Unit_Standard_pure_xZ5Us-xI4Uu8OVT5uDFW6A", "xsiNil": "false" } } }, "segmentCount": 337, "tag": { "dei_AmendmentFlag": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.", "label": "Amendment Flag" } } }, "localname": "AmendmentFlag", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_CityAreaCode": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Area code of city", "label": "City Area Code" } } }, "localname": "CityAreaCode", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_CurrentFiscalYearEndDate": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "End date of current fiscal year in the format --MM-DD.", "label": "Current Fiscal Year End Date" } } }, "localname": "CurrentFiscalYearEndDate", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "gMonthDayItemType" }, "dei_DocumentAnnualReport": { "auth_ref": [ "r843" ], "lang": { "en-US": { "role": { "documentation": "Boolean flag that is true only for a form used as an annual report.", "label": "Document Annual Report" } } }, "localname": "DocumentAnnualReport", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentFiscalPeriodFocus": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Fiscal period values are FY, Q1, Q2, and Q3. 1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY.", "label": "Document Fiscal Period Focus" } } }, "localname": "DocumentFiscalPeriodFocus", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "fiscalPeriodItemType" }, "dei_DocumentFiscalYearFocus": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.", "label": "Document Fiscal Year Focus" } } }, "localname": "DocumentFiscalYearFocus", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "gYearItemType" }, "dei_DocumentPeriodEndDate": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.", "label": "Document Period End Date" } } }, "localname": "DocumentPeriodEndDate", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "dateItemType" }, "dei_DocumentTransitionReport": { "auth_ref": [ "r842" ], "lang": { "en-US": { "role": { "documentation": "Boolean flag that is true only for a form used as a transition report.", "label": "Document Transition Report" } } }, "localname": "DocumentTransitionReport", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_DocumentType": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.", "label": "Document Type" } } }, "localname": "DocumentType", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "submissionTypeItemType" }, "dei_EntityAddressAddressLine1": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Address Line 1 such as Attn, Building Name, Street Name", "label": "Entity Address, Address Line One" } } }, "localname": "EntityAddressAddressLine1", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressCityOrTown": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Name of the City or Town", "label": "Entity Address, City or Town" } } }, "localname": "EntityAddressCityOrTown", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressPostalZipCode": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Code for the postal or zip code", "label": "Entity Address, Postal Zip Code" } } }, "localname": "EntityAddressPostalZipCode", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityAddressStateOrProvince": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Name of the state or province.", "label": "Entity Address, State or Province" } } }, "localname": "EntityAddressStateOrProvince", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "stateOrProvinceItemType" }, "dei_EntityCentralIndexKey": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.", "label": "Entity Central Index Key" } } }, "localname": "EntityCentralIndexKey", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "centralIndexKeyItemType" }, "dei_EntityCommonStockSharesOutstanding": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.", "label": "Entity Common Stock, Shares Outstanding" } } }, "localname": "EntityCommonStockSharesOutstanding", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "sharesItemType" }, "dei_EntityCurrentReportingStatus": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure.", "label": "Entity Current Reporting Status" } } }, "localname": "EntityCurrentReportingStatus", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "All the names of the entities being reported upon in a document. Any legal structure used to conduct activities or to hold assets. Some examples of such structures are corporations, partnerships, limited liability companies, grantor trusts, and other trusts. This item does not include business and geographical segments which are included in the geographical or business segments domains.", "label": "Entity [Domain]", "terseLabel": "Entity [Domain]" } } }, "localname": "EntityDomain", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "domainItemType" }, "dei_EntityEmergingGrowthCompany": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "Indicate if registrant meets the emerging growth company criteria.", "label": "Entity Emerging Growth Company" } } }, "localname": "EntityEmergingGrowthCompany", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_EntityFileNumber": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.", "label": "Entity File Number" } } }, "localname": "EntityFileNumber", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "fileNumberItemType" }, "dei_EntityFilerCategory": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure.", "label": "Entity Filer Category" } } }, "localname": "EntityFilerCategory", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "filerCategoryItemType" }, "dei_EntityIncorporationStateCountryCode": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Two-character EDGAR code representing the state or country of incorporation.", "label": "Entity Incorporation, State or Country Code" } } }, "localname": "EntityIncorporationStateCountryCode", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "edgarStateCountryItemType" }, "dei_EntityInteractiveDataCurrent": { "auth_ref": [ "r845" ], "lang": { "en-US": { "role": { "documentation": "Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).", "label": "Entity Interactive Data Current" } } }, "localname": "EntityInteractiveDataCurrent", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityPublicFloat": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold, or the average bid and asked price of such common equity, as of the last business day of the registrant's most recently completed second fiscal quarter.", "label": "Entity Public Float" } } }, "localname": "EntityPublicFloat", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "monetaryItemType" }, "dei_EntityRegistrantName": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.", "label": "Entity Registrant Name" } } }, "localname": "EntityRegistrantName", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_EntityShellCompany": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act.", "label": "Entity Shell Company" } } }, "localname": "EntityShellCompany", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_EntitySmallBusiness": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "Indicates that the company is a Smaller Reporting Company (SRC).", "label": "Entity Small Business" } } }, "localname": "EntitySmallBusiness", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "booleanItemType" }, "dei_EntityTaxIdentificationNumber": { "auth_ref": [ "r844" ], "lang": { "en-US": { "role": { "documentation": "The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.", "label": "Entity Tax Identification Number" } } }, "localname": "EntityTaxIdentificationNumber", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "employerIdItemType" }, "dei_EntityVoluntaryFilers": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Indicate 'Yes' or 'No' if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.", "label": "Entity Voluntary Filers" } } }, "localname": "EntityVoluntaryFilers", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_EntityWellKnownSeasonedIssuer": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Indicate 'Yes' or 'No' if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A.", "label": "Entity Well-known Seasoned Issuer" } } }, "localname": "EntityWellKnownSeasonedIssuer", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "yesNoItemType" }, "dei_LegalEntityAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The set of legal entities associated with a report.", "label": "Legal Entity [Axis]" } } }, "localname": "LegalEntityAxis", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "stringItemType" }, "dei_LocalPhoneNumber": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Local phone number for entity.", "label": "Local Phone Number" } } }, "localname": "LocalPhoneNumber", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "normalizedStringItemType" }, "dei_Security12bTitle": { "auth_ref": [ "r840" ], "lang": { "en-US": { "role": { "documentation": "Title of a 12(b) registered security.", "label": "Title of 12(b) Security" } } }, "localname": "Security12bTitle", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "securityTitleItemType" }, "dei_SecurityExchangeName": { "auth_ref": [ "r841" ], "lang": { "en-US": { "role": { "documentation": "Name of the Exchange on which a security is registered.", "label": "Security Exchange Name" } } }, "localname": "SecurityExchangeName", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "edgarExchangeCodeItemType" }, "dei_TradingSymbol": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Trading symbol of an instrument as listed on an exchange.", "label": "Trading Symbol" } } }, "localname": "TradingSymbol", "nsuri": "http://xbrl.sec.gov/dei/2019-01-31", "presentation": [ "http://principal.com/role/DocumentDocumentAndEntityInformation" ], "xbrltype": "tradingSymbolItemType" }, "pfg_AccumulatedNoncreditOtherThanTemporaryImpairmentIncludingPortionAttributableToNoncontrollingInterestMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents accumulated other comprehensive income related to noncredit other-than-temporary impairments of debt securities for which the credit portion of an other-than-temporary impairment has been recognized in earnings including the portion attributable to the noncontrolling interest.", "label": "Accumulated Noncredit Other Than Temporary Impairment Including Portion Attributable To Noncontrolling Interest [Member]", "terseLabel": "Noncredit component of impairment losses on fixed maturities available-for-sale including NCI" } } }, "localname": "AccumulatedNoncreditOtherThanTemporaryImpairmentIncludingPortionAttributableToNoncontrollingInterestMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "pfg_AccumulatedNoncreditOtherThanTemporaryImpairmentMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents accumulated other comprehensive income related to noncredit other-than-temporary impairments of debt securities for which the credit portion of an other-than-temporary impairment has been recognized in earnings, attributable to the parent.", "label": "Accumulated Noncredit Other Than Temporary Impairment [Member]", "terseLabel": "Noncredit component of impairment losses on fixed maturities available-for-sale" } } }, "localname": "AccumulatedNoncreditOtherThanTemporaryImpairmentMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "domainItemType" }, "pfg_AccumulatedOtherComprehensiveIncomeLossOtherThanTemporaryImpairmentNotCreditLossAvailableForSaleDebtSecurities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 2.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income or loss related to other-than-temporary impairment not a credit loss for available-for-sale debt securities.", "label": "Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Available-for-sale, Debt Securities", "terseLabel": "Noncredit component of impairment losses on fixed maturities, available-for-sale" } } }, "localname": "AccumulatedOtherComprehensiveIncomeLossOtherThanTemporaryImpairmentNotCreditLossAvailableForSaleDebtSecurities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsAssumedChangesAmortizationPatterns": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 3.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the cumulative net unrealized gains/losses adjustment related to deferred acquisition costs, sales inducements and unearned revenue reserves.", "label": "Adjustments, Assumed Changes, Amortization Patterns", "terseLabel": "Adjustments for assumed changes in amortization patterns" } } }, "localname": "AdjustmentsAssumedChangesAmortizationPatterns", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsAssumedChangesLiabilityForPolicyholderBenefitsAndClaims": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 4.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the cumulative net unrealized gains/losses adjustment related to changes in policyholder benefits and claims and changes in the policyholder dividend obligation.", "label": "Adjustments, Assumed Changes, Liability for Policyholder Benefits and Claims", "terseLabel": "Adjustments for assumed changes in policyholder liabilities" } } }, "localname": "AdjustmentsAssumedChangesLiabilityForPolicyholderBenefitsAndClaims", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInAmortizationPatternsBeforeTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 2.0, "parentTag": "pfg_AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax", "weight": 1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 3.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before tax of change in accumulated gains and losses associated with amortization of deferred acquisition costs and other actuarial balances such as sales inducements and unearned revenue.", "label": "Adjustments for Assumed Changes in Amortization Patterns before Tax", "negatedLabel": "Adjustments for assumed changes in amortization patterns, pre-tax" } } }, "localname": "AdjustmentsForAssumedChangesInAmortizationPatternsBeforeTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 3.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of change in accumulated gains and losses associated with amortization of deferred acquisition costs and other actuarial balances such as sales inducements and unearned revenue.", "label": "Adjustments for Assumed Changes in Amortization Patterns, Net of Tax", "negatedTotalLabel": "Adjustments for assumed changes in amortization patterns, after-tax" } } }, "localname": "AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInAmortizationPatternsTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 1.0, "parentTag": "pfg_AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax", "weight": -1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of tax expense (benefit) related to change in accumulated gains and losses associated with amortization of deferred acquisition costs and other actuarial balances such as sales inducements and unearned revenue.", "label": "Adjustments for Assumed Changes in Amortization Patterns Tax", "terseLabel": "Adjustments for assumed changes in amortization patterns, tax" } } }, "localname": "AdjustmentsForAssumedChangesInAmortizationPatternsTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsBeforeTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 1.0, "parentTag": "pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsNetOfTax", "weight": 1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 4.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before tax of adjustments for assumed changes in policyholder liabilities, including the amount by which the liability for policyholder benefits and claims would change if all unrealized gains/losses for the period were realized and for changes in the policyholder dividend obligation.", "label": "Adjustments for Assumed Changes in Liability for Policyholder Benefits and Claims Before Tax", "negatedLabel": "Adjustments for assumed changes in policyholder liabilities, pre-tax" } } }, "localname": "AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsBeforeTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsNetOfTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 4.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of adjustments for assumed changes in policyholder liabilities, including the amount by which the liability for policyholder benefits and claims would change if all unrealized gains/losses for the period were realized and for changes in the policyholder dividend obligation.", "label": "Adjustments for Assumed Changes in Liability for Policyholder Benefits and Claims Net of Tax", "negatedTotalLabel": "Adjustments for assumed changes in policyholder liabilities, after-tax" } } }, "localname": "AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsTax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 2.0, "parentTag": "pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsNetOfTax", "weight": -1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 4.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of tax expense (benefit) related to assumed changes in policyholder liabilities, including the amount by which the liability for policyholder benefits and claims would change if all unrealized gains/losses for the period were realized and for changes in the policyholder dividend obligation.", "label": "Adjustments for Assumed Changes in Liability for Policyholder Benefits and Claims, Tax", "terseLabel": "Adjustments for assumed changes in policyholder liabilities, tax" } } }, "localname": "AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AdjustmentsToRedemptionAmountOfRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents an increase in redeemable noncontrolling interest due to a current period change in the redemption value of redeemable noncontrolling interest and a classification error of certain noncontrolling interests, which resulted in a reclassification from stockholders' equity to redeemable noncontrolling interests.", "label": "Adjustments to Redemption Amount of Redeemable Noncontrolling Interest", "terseLabel": "Adjustments to redemption amount of redeemable noncontrolling interest" } } }, "localname": "AdjustmentsToRedemptionAmountOfRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "pfg_AdmittedAssetsUnderPrescribedAndPermittedStatutoryAccountingPractices": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount as of the balance sheet date of assets admitted due to applying state prescribed and permitted statutory accounting practices rather than statutory accounting practices prescribed by the National Association of Insurance Commissioners.", "label": "Admitted Assets Under Prescribed and Permitted Statutory Accounting Practices", "verboseLabel": "Admitted assets under prescribed and permitted statutory accounting practices" } } }, "localname": "AdmittedAssetsUnderPrescribedAndPermittedStatutoryAccountingPractices", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AgentMedicalAndLifePlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A postretirement benefit plan that specifically covers medical and life insurance costs for agents.", "label": "Agent Medical And Life Plan [Member]", "terseLabel": "Agent medical and life plans" } } }, "localname": "AgentMedicalAndLifePlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_AlternativeMutualFundMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Alternative investment instrument that invests principally in equities, corporate bonds, foreign currencies, convertible securities and derivatives.", "label": "Alternative Mutual Fund [Member]", "terseLabel": "Alternative mutual fund portfolios" } } }, "localname": "AlternativeMutualFundMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_AlternativesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Alternative investment instrument that invests in a hedge fund separate account.", "label": "Alternatives [Member]", "terseLabel": "Alternatives" } } }, "localname": "AlternativesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "pfg_AvailableForSaleDebtSecuritiesHedgingNet": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 4.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the net gains/losses on available-for-sale debt securities that are the hedged item in a designated fair value hedge.", "label": "Available-for-sale Debt Securities, Hedging, Net", "verboseLabel": "Fixed maturities, available-for-sale: Hedging, net" } } }, "localname": "AvailableForSaleDebtSecuritiesHedgingNet", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLossesOnInvestmentGradeInvestmentsLessThanTwelveMonths": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item contains disclosure of the unrealized losses on securities in the available-for-sale investments portfolio (that is determined to be temporarily impaired) that has been in an unrealized loss position less than twelve months that is deemed to be investment grade.", "label": "Available- for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses On Investment Grade Investments, Less Than Twelve Months", "terseLabel": "Available-for-sale Securities in Unrealized Loss Position, Aggregate Losses On Investment Grade Investments, Less Than Twelve Months" } } }, "localname": "AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLossesOnInvestmentGradeInvestmentsLessThanTwelveMonths", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Proceeds from sales of investments" } } }, "localname": "AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "stringItemType" }, "pfg_AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePrice": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure regarding factors used to determine that the impairment of securities not categorized as either held-to-maturity or trading securities (hence equal to available-for-sale securities) where cost exceeds fair value is not an other-than-temporary impairment. This item contains disclosure of the average price of available-for-sale investments determined to be temporarily impaired. It is the calculated result of dividing the carrying value by amortized cost.", "label": "Available-for-sale Securities in Unrealized Loss Positions, Average Price", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Average Price (percent of carrying value to amortized cost)" } } }, "localname": "AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePrice", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "integerItemType" }, "pfg_AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePriceLessThanTwelveMonths": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure regarding factors used to determine that the impairment of securities not categorized as either held-to-maturity securities or trading securities (hence equal to available for sale securities) where cost exceeds fair value is not an other than temporary impairment. This item contains disclosure of the average price of available-for-sale investments determined to be temporarily impaired and have been in a loss position for less than twelve months. It is the calculated result of dividing the carrying value by amortized cost.", "label": "Available-for-sale Securities, Unrealized Loss Positions, Average Price, Less Than Twelve Months", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Average Price, Less Than Twelve Months (percent of carrying value to amortized cost)" } } }, "localname": "AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePriceLessThanTwelveMonths", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "integerItemType" }, "pfg_AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePriceTwelveMonthsOrLonger": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure regarding factors used to determine that the impairment of securities not categorized as either held-to-maturity securities or trading securities (hence equal to available for sale securities) where cost exceeds fair value is not an other than temporary impairment. This item contains disclosure of the average price of available-for-sale investments determined to be temporarily impaired and have been in a loss position for greater than or equal to twelve months. It is the calculated result of dividing the carrying value by amortized cost.", "label": "Available-for-sale Securities, Unrealized Loss Positions, Average Price, Twelve Months or Longer", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost)" } } }, "localname": "AvailableForSaleSecuritiesUnrealizedLossPositionsAveragePriceTwelveMonthsOrLonger", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "integerItemType" }, "pfg_AvailableForSaleSecuritiesUnrealizedLossPositionsPercentInvestmentGrade": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure regarding factors used to determine that the impairment of securities not categorized as either held-to-maturity or trading securities (hence equal to available-for-sale securities) where cost exceeds fair value is not an other-than-temporary impairment. This item contains disclosure of the percent of investments that are investment grade in the available-for-sale investments determined to be temporarily impaired.", "label": "Available-for-sale Securities, Unrealized Loss Positions, Percent Investment Grade", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Percent Investment Grade (as a percent)" } } }, "localname": "AvailableForSaleSecuritiesUnrealizedLossPositionsPercentInvestmentGrade", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "percentItemType" }, "pfg_AvailableForSaleSecuritiesUnrealizedLossPositionsPercentInvestmentGradeLessThanTwelveMonths": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure regarding factors used to determine that the impairment of securities not categorized as either held-to-maturity securities or trading securities (hence equal to available for sale securities) where cost exceeds fair value is not an other than temporary impairment. This item contains disclosure of the percent of investments that are investment grade in the available-for-sale investments determined to be temporarily impaired and have been in a loss position for less than twelve months.", "label": "Available-for-sale Securities in Unrealized Loss Positions, Percent Investment Grade, Less Than Twelve Months", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Percent Investment Grade, Less Than Twelve Months (as a percent)" } } }, "localname": "AvailableForSaleSecuritiesUnrealizedLossPositionsPercentInvestmentGradeLessThanTwelveMonths", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "percentItemType" }, "pfg_BackStopFacilityOutstandingBalances": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of outstanding back-stop facilities as of the balance sheet date.", "label": "Back Stop Facility Outstanding Balances", "terseLabel": "Back-stop facility outstanding balances" } } }, "localname": "BackStopFacilityOutstandingBalances", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "pfg_BackStopFacilitySupportForCommercialPaperProgramPercent": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage of support provided by back-stop facility for commercial paper program.", "label": "Back Stop Facility Support for Commercial Paper Program Percent", "terseLabel": "Support provided by back-stop facility for commercial paper program (as a percent)" } } }, "localname": "BackStopFacilitySupportForCommercialPaperProgramPercent", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "percentItemType" }, "pfg_BalancedAssetAllocationPortfoliosMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Investment in a combination of underlying fixed income and equity investment options. These investment options may include balanced, asset allocation, target-date and target-risk investment options. Although typically lower risk than investment options that invest solely in equities, all investment options in this category have the potential to lose value.", "label": "Balanced Asset Allocation Portfolios [Member]", "terseLabel": "Balanced asset allocation portfolios" } } }, "localname": "BalancedAssetAllocationPortfoliosMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_BenefitsClaimsAndSettlementExpensesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The total amount of expense recognized during the period for future policy benefits, claims and claims adjustment costs.", "label": "Benefits Claims And Settlement Expenses [Member]", "terseLabel": "Benefits, claims and settlement expenses" } } }, "localname": "BenefitsClaimsAndSettlementExpensesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_CapitalGainsLossesDistributed": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 3.0, "parentTag": "pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in benefits, claims and settlement expenses to net realized capital gains (losses) for segment profit (loss) reporting related to net realized capital gains (losses) distributed to participating insurance or investment contract participants through interest crediting.", "label": "Capital (Gains) Losses Distributed", "negatedLabel": "Capital (gains) losses distributed" } } }, "localname": "CapitalGainsLossesDistributed", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CapitalReceivedFromDividendsPaidToParent": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 11.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents disclosure of the amount of capital received from parent or dividends, capital and other distributions made to parent for unconsolidated subsidiaries accounted for using the equity method of accounting.", "label": "Capital Received from Dividends Paid to Parent", "terseLabel": "Capital received from (dividends and capital paid to) parent" } } }, "localname": "CapitalReceivedFromDividendsPaidToParent", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CashAndCashEquivalentFairValueDisclosure": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Includes currency on hand and other cash equivalents not required to be reported at fair value.", "label": "Cash and Cash Equivalent, Fair Value Disclosure", "verboseLabel": "Cash and cash equivalents not required to be reported at fair value" } } }, "localname": "CashAndCashEquivalentFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CashAndCashEquivalentsMaximumMaturityPeriod": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the maximum number of months for the maturity date of an investment when purchased for it to be included in cash and cash equivalents.", "label": "Cash and Cash Equivalents Maximum Maturity Period", "terseLabel": "Maximum maturity period when purchased for investments to be included in cash and cash equivalents" } } }, "localname": "CashAndCashEquivalentsMaximumMaturityPeriod", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesCashAndCashEquivalentsInvestmentsDetails" ], "xbrltype": "durationItemType" }, "pfg_CashCollateralLiabilityFairValueDisclosure": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the obligation to return cash received as collateral from counterparties.", "label": "Cash Collateral, Liability, Fair Value Disclosure", "negatedLabel": "Cash collateral payable" } } }, "localname": "CashCollateralLiabilityFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CashCollateralReceivedAssociatedWithDerivatives": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The carrying value as of the balance sheet date of the cash received as collateral associated with derivative credit support annex agreements and Futures Commission Merchant agreements.", "label": "Cash Collateral Received Associated with Derivatives", "terseLabel": "Cash collateral received associated with derivative credit support annex agreements and Futures Commission Merchant agreements" } } }, "localname": "CashCollateralReceivedAssociatedWithDerivatives", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CashReceivedFromSharesIssued": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Aggregate proceeds received by the entity during the period from issuance of shares under share-based payment arrangements.", "label": "Cash Received From Shares Issued", "terseLabel": "Cash received from shares issued" } } }, "localname": "CashReceivedFromSharesIssued", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CertainInvestmentFundsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Certain investment funds where we elect the fair value option to reflect the economics of the investment.", "label": "Certain Investment Funds [Member]", "terseLabel": "Investment Funds" } } }, "localname": "CertainInvestmentFundsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_CertainSponsoredInvestmentFunds": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The net investment in unconsolidated sponsored investment funds and the invested assets of consolidated sponsored investments funds, which are carried at fair value.", "label": "Certain Sponsored Investment Funds", "terseLabel": "Certain sponsored investment funds carried at fair value" } } }, "localname": "CertainSponsoredInvestmentFunds", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedCumulativeEffectOfNewAccountingPrinciple": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in the carrying amount of closed block liabilities in excess of the carrying amount of closed block assets at the date of demutualization (adjusted to eliminate the impact of related amounts in accumulated other comprehensive income), resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.", "label": "Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized, Cumulative Effect of New Accounting Principle", "negatedLabel": "Effects of implementation of accounting changes" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedCumulativeEffectOfNewAccountingPrinciple", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureClosedBlockChangeInMaximumFutureEarningsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ClosedBlockOperationsBenefitClaimsAndSettlementExpenses": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockOperationsBenefitsAndExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Provision for benefits, claims and claims settlement expenses incurred during the period allocated to an insurance entity's segregated group of participating or dividend-paying policies and contracts (known as a closed block).", "label": "Closed Block Operations Benefit Claims and Settlement Expenses", "terseLabel": "Closed Block: Benefits, claims and settlement expenses" } } }, "localname": "ClosedBlockOperationsBenefitClaimsAndSettlementExpenses", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ClosedBlockOperationsFundingAdjustmentCharges": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amounts charged to the closed block during the period necessary to properly fund for certain adjustments, such as face amount and premium increases, due to the adjustable life policies included in the closed block.", "label": "Closed Block Operations Funding Adjustment Charges", "negatedLabel": "Funding adjustment charges" } } }, "localname": "ClosedBlockOperationsFundingAdjustmentCharges", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ClosedBlockOperationsOperatingExpenses": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 3.0, "parentTag": "us-gaap_ClosedBlockOperationsBenefitsAndExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Operating expenses impacting an insurance entity's segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block).", "label": "Closed Block Operations Operating Expenses", "terseLabel": "Closed Block: Operating expenses" } } }, "localname": "ClosedBlockOperationsOperatingExpenses", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CollateralPledgedLiabilitiesSubjectToNettingNotOffset": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails": { "order": 3.0, "parentTag": "pfg_NetAmountLiabilitiesSubjectToNetting", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Collateral received for derivative and other financial liabilities (repurchase agreements and securities borrowing transactions) subject to master netting agreements or similar agreements.", "label": "Collateral Pledged Liabilities Subject to Netting Not Offset", "negatedLabel": "Collateral pledged, financial liabilities" } } }, "localname": "CollateralPledgedLiabilitiesSubjectToNettingNotOffset", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CollateralReceivedAssetsSubjectToNettingNotOffset": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails": { "order": 3.0, "parentTag": "pfg_NetAmountAssetsSubjectToNetting", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Collateral received for derivative and other financial assets (reverse repurchase agreements and securities lending transactions) subject to master netting agreements or similar agreements.", "label": "Collateral Received Assets Subject to Netting Not Offset", "negatedLabel": "Collateral received, financial assets" } } }, "localname": "CollateralReceivedAssetsSubjectToNettingNotOffset", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CommercialBrickAndMortarMortgageMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Commercial mortgage loans analyzed based on the property's rent payments as support for the loan.", "label": "Commercial Brick And Mortar Mortgage [Member]", "terseLabel": "Brick and mortar" } } }, "localname": "CommercialBrickAndMortarMortgageMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "pfg_CommercialCreditTenantMortgageMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Commercial mortgage loans where the credit analysis of the tenant for the repayment of the loans is relied on.", "label": "Commercial Credit Tenant Mortgage [Member]", "terseLabel": "Credit tenant loans" } } }, "localname": "CommercialCreditTenantMortgageMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "pfg_CommercialMortgageLoansOfConsolidatedVariableInterestEntitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio, of consolidated variable interest entities for which the fair value option was elected.", "label": "Commercial Mortgage Loans Of Consolidated Variable Interest Entities [Member]", "terseLabel": "Commercial Mortgage Loans of Consolidated VIEs" } } }, "localname": "CommercialMortgageLoansOfConsolidatedVariableInterestEntitiesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_CommissionIncomeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Commission income from brokerage services.", "label": "Commission Income [Member]", "terseLabel": "Commission income" } } }, "localname": "CommissionIncomeMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_CondensedConsolidatingFinancialInformationDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Condensed Consolidating Financial Information" } } }, "localname": "CondensedConsolidatingFinancialInformationDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_CondensedConsolidatingFinancialInformationNotesGuarantorLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items for the schedule that includes condensed consolidating financial information of parent companies and/or subsidiaries that are issuers and guarantors of guaranteed securities.", "label": "Condensed Consolidating Financial Information - Notes Guarantor [Line Items]" } } }, "localname": "CondensedConsolidatingFinancialInformationNotesGuarantorLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "pfg_CondensedConsolidatingFinancialInformationNotesGuarantorTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Dimension comprising the condensed financial statements (balance sheet, income statement and statement of cash flows), normally using the registrant (parent) as the sole domain member. If condensed consolidating financial statements are being presented, other domain members (in addition to parent) such as guarantor subsidiaries, non-guarantor subsidiaries, and the consolidation eliminations, will be included in order that the respective monetary amounts for each of the domains will aggregate to the respective amounts on the consolidated financial statements. The line items are the various captions used to compile the condensed financial statements. Using extensions, most, if not all, of the elements representing condensed financial statement captions will be the same as those used for the consolidated financial statements captions. This table is for a parent's guarantee of medium term notes issued by a subsidiary.", "label": "Condensed Consolidating Financial Information - Notes Guarantor [Table]" } } }, "localname": "CondensedConsolidatingFinancialInformationNotesGuarantorTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "pfg_CondensedConsolidatingFinancialInformationShelfRegistrationDebtGuarantorLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items for the schedule that includes condensed consolidating financial information of parent companies and/or subsidiaries that are issuers and guarantors of guaranteed securities related to shelf registration debt.", "label": "Condensed Consolidating Financial Information - Shelf Registration Debt Guarantor [Line Items]" } } }, "localname": "CondensedConsolidatingFinancialInformationShelfRegistrationDebtGuarantorLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "pfg_CondensedConsolidatingFinancialInformationShelfRegistrationDebtGuarantorTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Dimension comprising the condensed financial statements (balance sheet, income statement and statement of cash flows), normally using the registrant (parent) as the sole domain member. If condensed consolidating financial statements are being presented, other domain members (in addition to parent) such as guarantor subsidiaries, non-guarantor subsidiaries, and the consolidation eliminations, will be included in order that the respective monetary amounts for each of the domains will aggregate to the respective amounts on the consolidated financial statements. The line items are the various captions used to compile the condensed financial statements. Using extensions, most, if not all, of the elements representing condensed financial statement captions will be the same as those used for the consolidated financial statements captions. This table is for a subsidiary's guarantee of securities issued under a shelf registration of its parent.", "label": "Condensed Consolidating Financial Information - Shelf Registration Debt Guarantor [Table]" } } }, "localname": "CondensedConsolidatingFinancialInformationShelfRegistrationDebtGuarantorTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "pfg_ConsolidatedVariableInterestEntityAssetsLiabilitiesTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A tabular comparison of the carrying amount of the assets and liabilities of consolidated variable interest entities.", "label": "Consolidated Variable Interest Entity, Assets (Liabilities) [Table]" } } }, "localname": "ConsolidatedVariableInterestEntityAssetsLiabilitiesTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "pfg_ConsolidationEliminationsAndOtherNotesGuarantorMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Intercompany transactions between Principal Financial Group, Inc.; Principal Life Insurance Company; and Principal Financial Services, Inc. and Other Subsidiaries Combined.", "label": "Consolidation Eliminations And Other Notes Guarantor [Member]", "terseLabel": "Eliminations, Notes Guarantor" } } }, "localname": "ConsolidationEliminationsAndOtherNotesGuarantorMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_ConsolidationEliminationsAndOtherShelfRegistrationDebtGuarantorMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Intercompany transactions between Principal Financial Group, Inc.; Principal Financial Services, Inc.; and Principal Life Insurance Company and Other Subsidiaries Combined.", "label": "Consolidation Eliminations And Other Shelf Registration Debt Guarantor [Member]", "terseLabel": "Eliminations, Shelf Registration Debt Guarantor" } } }, "localname": "ConsolidationEliminationsAndOtherShelfRegistrationDebtGuarantorMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_ContingenciesGuaranteesIndemnificationsAndLeasesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Contingencies, Guarantees, Indemnifications and Leases" } } }, "localname": "ContingenciesGuaranteesIndemnificationsAndLeasesDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_ContingentFundingAgreement10YearMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Ten-year contingent funding agreement with a Delaware trust formed by the entity, providing a put option under which the entity has the right to sell senior notes to the trust.", "label": "Contingent Funding Agreement10 Year [Member]", "terseLabel": "10-year contingent funding agreement" } } }, "localname": "ContingentFundingAgreement10YearMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_ContingentFundingAgreement30YearMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Thirty-year contingent funding agreement with a Delaware trust formed by the entity, providing a put option under which the entity has the right to sell senior notes to the trust.", "label": "Contingent Funding Agreement30 Year [Member]", "terseLabel": "30-year contingent funding agreement" } } }, "localname": "ContingentFundingAgreement30YearMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_ContingentFundingAgreementMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Contingent funding agreements entered into by the entity.", "label": "Contingent Funding Agreement [Member]", "terseLabel": "Contingent funding agreements" } } }, "localname": "ContingentFundingAgreementMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_ContractholderAndOtherPolicyholderFunds": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Contractholder funds include reserves for investment contracts and reserves for universal life insurance. Other policyholder funds represent the liability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.", "label": "Contractholder and Other Policyholder Funds", "terseLabel": "Contractholder and other policyholder funds" } } }, "localname": "ContractholderAndOtherPolicyholderFunds", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ContractholderAndPolicyholderLiabilitiesPolicyTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for accounting for contractholder funds; future policy benefits and claims; and other policyholder funds. Disclosure may include information on how reserves are established, the extent of participating business, and accounting for unearned revenue.", "label": "Contractholder and Policyholder Liabilities Policy [Text Block]", "terseLabel": "Contractholder and Policyholder Liabilities - Policy" } } }, "localname": "ContractholderAndPolicyholderLiabilitiesPolicyTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "pfg_ContractholderFunds": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Contractholder funds include reserves for investment contracts and reserves for universal life insurance.", "label": "Contractholder Funds", "terseLabel": "Contractholder funds", "totalLabel": "Contractholder funds", "verboseLabel": "Contractholder funds (2019 and 2018 include $394.6 million and $396.0 million related to consolidated variable interest entities)" } } }, "localname": "ContractholderFunds", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "pfg_ContributionsToRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents an increase in redeemable noncontrolling interest from issuance of additional equity interests that occurred during the period.", "label": "Contributions to Redeemable Noncontrolling Interest", "terseLabel": "Contributions from redeemable noncontrolling interest" } } }, "localname": "ContributionsToRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CorporateAndRegionalMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Corporate and regional locations not otherwise specified.", "label": "Corporate And Regional [Member]", "terseLabel": "Principal International Corporate / Regional Office" } } }, "localname": "CorporateAndRegionalMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_CreditDerivativeSoldNotional": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Discloses the notional amount of the credit derivatives sold (or each group of similar credit derivatives) as of the date of the statement of financial position.", "label": "Credit Derivative Sold, Notional", "terseLabel": "Notional amount" } } }, "localname": "CreditDerivativeSoldNotional", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CreditDerivativesSoldFairValue": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Discloses the fair value of the credit derivatives sold (or each group of similar credit derivatives) as of the date of the statement of financial position.", "label": "Credit Derivatives Sold, Fair Value", "terseLabel": "Fair value" } } }, "localname": "CreditDerivativesSoldFairValue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "monetaryItemType" }, "pfg_CreditDerivativesSoldWeightedAverageExpectedLife": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the weighted-average expected life in years for credit derivatives sold.", "label": "Credit Derivatives Sold, Weighted Average Expected Life", "terseLabel": "Weighted average expected life" } } }, "localname": "CreditDerivativesSoldWeightedAverageExpectedLife", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "durationItemType" }, "pfg_CreditFacilityMaturingNovember2023Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Credit facility entered into by the entity with maturity in November 2023.", "label": "Credit Facility Maturing November2023 [Member]", "terseLabel": "Credit facility maturing November 2023" } } }, "localname": "CreditFacilityMaturingNovember2023Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_CumulativeEffectOfProspectiveApplicationOfNewAccountingPrincipleNetOfTax": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of cumulative effect adjustment on equity or net assets for prospective application of a new accounting principle.", "label": "Cumulative Effect Of Prospective Application Of New Accounting Principle, Net Of Tax", "terseLabel": "Cumulative effect adjustment from adopting guidance", "verboseLabel": "Effects of implementation of accounting change" } } }, "localname": "CumulativeEffectOfProspectiveApplicationOfNewAccountingPrincipleNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "pfg_CurrentIncomeTaxReceivablesAssociatedWithOutstandingAuditsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Current income tax receivables associated with outstanding audits", "terseLabel": "Current income tax receivables associated with outstanding audit issues" } } }, "localname": "CurrentIncomeTaxReceivablesAssociatedWithOutstandingAuditsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "pfg_CurrentTaxBenefitOfOperatingLossCarryForwards": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 4.0, "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The current tax benefit received due to operating loss carryforwards.", "label": "Current Tax Benefit of Operating Loss Carry Forwards", "negatedLabel": "Current income taxes (benefits): Tax benefit of operating loss carryforwards" } } }, "localname": "CurrentTaxBenefitOfOperatingLossCarryForwards", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DaysDelinquentNonperforming": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The numbers of days for which a mortgage loan has been delinquent such that it is considered non-performing.", "label": "Days Delinquent Nonperforming", "terseLabel": "Mortgage loans, Days delinquent to be considered non-performing" } } }, "localname": "DaysDelinquentNonperforming", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "durationItemType" }, "pfg_DaysDelinquentValuationAllowance": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The numbers of days for which a mortgage loan has been delinquent such that it is analyzed to determine if a valuation allowance is needed.", "label": "Days Delinquent Valuation Allowance", "terseLabel": "Mortgage loans, Days delinquent to be analyzed for valuation allowance" } } }, "localname": "DaysDelinquentValuationAllowance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "durationItemType" }, "pfg_DebtInstrumentCarryingAmountHighEndOfRange": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents the high end of the range of the outstanding principal balances of mortgages and other notes payable per real estate development.", "label": "Debt Instrument, Carrying Amount High End of Range", "terseLabel": "Outstanding principal balances per real estate development, high end of range" } } }, "localname": "DebtInstrumentCarryingAmountHighEndOfRange", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DebtInstrumentCarryingAmountLowEndOfRange": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents the low end of the range of the outstanding principal balances of mortgages and other notes payable per real estate development.", "label": "Debt Instrument, Carrying Amount Low End of Range", "terseLabel": "Outstanding principal balances per real estate development, low end of range" } } }, "localname": "DebtInstrumentCarryingAmountLowEndOfRange", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredAcquisitionCostAndOtherActuarialBalancesAmortizationExpense": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 2.0, "parentTag": "pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in operating expenses and benefits, claims and settlement expenses to net realized capital gains (losses) for segment profit (loss) reporting related to the portion of amortization expense from deferred acquisition costs and other actuarial balances, respectively, attributable to the portion of estimated gross profits related to net realized capital gains (losses).", "label": "Deferred Acquisition Cost and Other Actuarial Balances, Amortization Expense", "negatedLabel": "Amortization of deferred acquisition costs and other actuarial balances" } } }, "localname": "DeferredAcquisitionCostAndOtherActuarialBalancesAmortizationExpense", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredAcquisitionCostTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of the reconciliation of deferred acquisition costs from the beginning of a period to the end of a period, including costs capitalized and amortized during the period.", "label": "Deferred Acquisition Cost [Text Block]", "terseLabel": "Deferred Acquisition Costs" } } }, "localname": "DeferredAcquisitionCostTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCosts" ], "xbrltype": "textBlockItemType" }, "pfg_DeferredIncomeTaxDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Deferred Income Tax Disclosures [Abstract]", "terseLabel": "Deferred income tax disclosures" } } }, "localname": "DeferredIncomeTaxDisclosuresAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "pfg_DeferredIncomeTaxDisclosuresOperatingLossCarryforwardsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Deferred Income Tax Disclosures Operating Loss Carryforwards [Abstract]", "terseLabel": "Deferred income tax disclosures-operating loss carryforwards" } } }, "localname": "DeferredIncomeTaxDisclosuresOperatingLossCarryforwardsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "pfg_DeferredPolicyAcquisitionCostAndCapitalizedContractCostAdditions": { "auth_ref": [], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 4.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The increase in deferred acquisition costs and contract costs due to costs capitalized during the income statement period.", "label": "Adjustment for Additions to Deferred Policy Acquisition Cost and Capitalized Contract Cost", "negatedLabel": "Additions to deferred acquisition costs and contract costs" } } }, "localname": "DeferredPolicyAcquisitionCostAndCapitalizedContractCostAdditions", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredPolicyAcquisitionCostAndCapitalizedContractCostAmortizationExpense": { "auth_ref": [], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 3.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense (reversal of expense) for deferred policy acquisition costs and capitalized cost incurred to obtain or fulfill contract with customer.", "label": "Deferred Policy Acquisition Cost and Capitalized Contract Cost, Amortization Expense", "terseLabel": "Amortization of deferred acquisition costs and contract costs" } } }, "localname": "DeferredPolicyAcquisitionCostAndCapitalizedContractCostAmortizationExpense", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredPolicyAcquisitionCostsOtherAdjustments": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in deferred policy acquisition cost (DAC) due to other adjustments not otherwise specified in the taxonomy.", "label": "Deferred Policy Acquisition Costs, Other Adjustments", "terseLabel": "Other" } } }, "localname": "DeferredPolicyAcquisitionCostsOtherAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxAssetsInvestmentIncludingDerivativeLiabilities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 2.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to investments, including derivative instruments, which can only be deducted for tax purposes when losses on such instruments are realized, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.", "label": "Deferred Tax Assets, Investment Including Derivative Liabilities", "terseLabel": "Investments, including derivative liabilities" } } }, "localname": "DeferredTaxAssetsInvestmentIncludingDerivativeLiabilities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxAssetsOperatingLossCapitalLossCarryforwards": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 3.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The sum of the tax effects as of the balance sheet date of (1) the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset and (2) the amount of future tax deductions arising from capital losses in excess of statutory limitations in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.", "label": "Deferred Tax Assets Operating Loss Capital Loss Carryforwards", "terseLabel": "Net operating and capital loss carryforwards" } } }, "localname": "DeferredTaxAssetsOperatingLossCapitalLossCarryforwards", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxLiabilitiesDeferredAcquisitionCosts": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 1.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and basis of deferred acquisition costs that were capitalized in conformity with generally accepted accounting principles. The difference in basis will reverse in future periods.", "label": "Deferred Tax Liabilities Deferred Acquisition Costs", "negatedLabel": "Deferred acquisition costs" } } }, "localname": "DeferredTaxLiabilitiesDeferredAcquisitionCosts", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxLiabilitiesInvestmentIncludingDerivativeAssets": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 2.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date for deferred tax consequences attributable to taxable temporary differences resulting from investments, including derivative transactions. Deferred tax consequences are future tax effects on income taxes as measured by the applicable enacted tax rate and provisions of the enacted tax law resulting from temporary differences and carryforwards.", "label": "Deferred Tax Liabilities Investment Including Derivative Assets", "negatedLabel": "Investments, including derivative assets" } } }, "localname": "DeferredTaxLiabilitiesInvestmentIncludingDerivativeAssets", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxLiabilitiesPolicyholderLiabilities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 6.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from policyholder liabilities.", "label": "Deferred Tax Liabilities, Policyholder Liabilities", "negatedLabel": "Insurance liabilities" } } }, "localname": "DeferredTaxLiabilitiesPolicyholderLiabilities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DeferredTaxLiabilitiesRealEstate": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 4.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis of real estate assets and the basis of real estate assets computed in accordance with generally accepted accounting principles. The difference in basis, attributable to different capitalization of costs, depreciation, or amortization methodologies, will increase future taxable income when such basis difference is realized.", "label": "Deferred Tax Liabilities Real Estate", "negatedLabel": "Real estate" } } }, "localname": "DeferredTaxLiabilitiesRealEstate", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DefinedBenefitPlanActuarialGainLossAmortizationDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Defined Benefit Plan Actuarial Gain (Loss) Amortization Disclosures [Abstract]", "terseLabel": "Plan actuarial gain and loss amortization disclosures" } } }, "localname": "DefinedBenefitPlanActuarialGainLossAmortizationDisclosuresAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "stringItemType" }, "pfg_DefinedBenefitPlanAdditionalDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Defined Benefit Plan Additional Disclosures [Abstract]", "terseLabel": "Additional defined benefit plan disclosures" } } }, "localname": "DefinedBenefitPlanAdditionalDisclosuresAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "stringItemType" }, "pfg_DefinedBenefitPlanEquitySecuritiesUsSmallMidCapMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Security representing ownership in corporation or other legal entity, domiciled in United States of America (US), classified as having small or medium market capitalization, for which ownership is represented by share of stock; in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant.", "label": "Defined Benefit Plan Equity Securities Us Small Mid Cap [Member]", "terseLabel": "U.S. small/mid cap equity portfolios" } } }, "localname": "DefinedBenefitPlanEquitySecuritiesUsSmallMidCapMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_DefinedBenefitPlanFairValueOfPlanAssetsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan Fair Value of Plan Assets [Abstract]", "terseLabel": "Defined benefit plan, fair value of plan assets" } } }, "localname": "DefinedBenefitPlanFairValueOfPlanAssetsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "stringItemType" }, "pfg_DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The final average pay benefit is based on the years of service and generally the employee's or agent's average annual compensation during the most recent years of employment for this time period.", "label": "Defined Benefit Plan, Final Average Pay Benefit Computation, Period of Employment", "terseLabel": "Period of employment used to calculate average annual compensation for the final average pay benefit" } } }, "localname": "DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails" ], "xbrltype": "durationItemType" }, "pfg_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearAge65AndOver": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan due to factors other than changes in the composition of the plan population by age and dependency status. This rate is for people age 65 and over.", "label": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year Age 65 and Over", "terseLabel": "Health care cost trend rate assumed for next year age 65 and over (as a percent)" } } }, "localname": "DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearAge65AndOver", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "pfg_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearUnderAge65": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan due to factors other than changes in the composition of the plan population by age and dependency status. This rate is for people under age 65.", "label": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year Under Age 65", "terseLabel": "Health care cost trend rate assumed for next year under age 65 (as a percent)" } } }, "localname": "DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearUnderAge65", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "pfg_DefinedBenefitPlanNonqualifiedPensionPlanMarketValueOfAssetsHeldInTrust": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The fair value of assets held in Rabbi trusts for the benefit of nonqualified pension plan participants. The assets held in the Rabbi trust are available to satisfy the claims of general creditors only in the event of bankruptcy. Therefore, they are fully consolidated in the consolidated statement of financial position and are not reflected in funded status as they do not qualify as plan assets.", "label": "Defined Benefit Plan, Nonqualified Pension Plan, Market Value of Assets Held in Trust", "terseLabel": "Market value of assets held in Rabbi trusts for benefit of nonqualified pension plan participants" } } }, "localname": "DefinedBenefitPlanNonqualifiedPensionPlanMarketValueOfAssetsHeldInTrust", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "For defined benefit plans, the allowance corridor, stated in a percentage, that is not used to amortize actuarial gains and losses for the qualified pension plan.", "label": "Defined Benefit Plan, Qualified Pension Plan, Actuarial Gains and Losses, Amortization, Allowance Corridor Not Used", "terseLabel": "Allowable corridor not used for amortization of actuarial gains and losses of qualified pension plan (as a percent)" } } }, "localname": "DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "percentItemType" }, "pfg_DefinedBenefitPlanTotalPlanAmendmentGainLossRecordedInAoci": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of defined benefit plan gain (loss) from effect of plan amendment, recorded in AOCI and amortized into earnings over time.", "label": "Defined Benefit Plan Total Plan Amendment Gain Loss Recorded In AOCI", "terseLabel": "Total plan amendment gain" } } }, "localname": "DefinedBenefitPlanTotalPlanAmendmentGainLossRecordedInAoci", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DefinedBenefitPlanYearThatRateReachesUltimateTrendRateAge65AndOver": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Year the ultimate health care cost trend rate is expected to be reached, in CCYY format. This year is for people age 65 and over.", "label": "Defined Benefit Plan Year that Rate Reaches Ultimate Trend Rate Age 65 and Over", "terseLabel": "Year that the health care cost trend rate reaches the ultimate trend rate age 65 and over (calendar year)" } } }, "localname": "DefinedBenefitPlanYearThatRateReachesUltimateTrendRateAge65AndOver", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "gYearItemType" }, "pfg_DefinedBenefitPlanYearThatRateReachesUltimateTrendRateUnderAge65": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Year the ultimate health care cost trend rate is expected to be reached, in CCYY format. This year is for people under age 65.", "label": "Defined Benefit Plan Year that Rate Reaches Ultimate Trend Rate under Age 65", "terseLabel": "Year that the health care cost trend rate reaches the ultimate trend rate under age 65 (calendar year)" } } }, "localname": "DefinedBenefitPlanYearThatRateReachesUltimateTrendRateUnderAge65", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "gYearItemType" }, "pfg_DefinedContributionPlanContributionsByEmployer": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of contributions made by the employer during the period to defined contribution plans.", "label": "Defined Contribution Plan, Contributions by Employer", "terseLabel": "Amount contributed by the employer to defined contribution plans" } } }, "localname": "DefinedContributionPlanContributionsByEmployer", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DefinedContributionPlanEligibilityAge": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The required age to be reached to be eligible for the defined contribution plan.", "label": "Defined Contribution Plan, Eligibility Age", "terseLabel": "Eligibility age to be able to elect to retain benefits in defined contribution plan" } } }, "localname": "DefinedContributionPlanEligibilityAge", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "durationItemType" }, "pfg_DefinedContributionPlanEligibilityServicePeriodForGrandfatheredChoiceParticipants": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The minimum service required, in years, to be eligible for the defined contribution plan.", "label": "Defined Contribution Plan, Eligibility Service Period", "terseLabel": "Minimum years of service to be able to elect to retain benefits in defined contribution plan" } } }, "localname": "DefinedContributionPlanEligibilityServicePeriodForGrandfatheredChoiceParticipants", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "durationItemType" }, "pfg_DefinedContributionPlanGeneralParticipantMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Defined contribution plans for participants who did not elect (or were not eligible to elect) to retain the prior benefit provisions and forgo receipt of the additional matching contributions.", "label": "Defined Contribution Plan General Participant [Member]", "terseLabel": "Defined contribution pension benefits - All other participants" } } }, "localname": "DefinedContributionPlanGeneralParticipantMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "domainItemType" }, "pfg_DefinedContributionPlanGrandfatheredChoiceParticipantMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Defined contribution plans for participants who elected to retain the prior benefit provisions and forgo receipt of the additional matching contributions. These participants are referred to as \"Grandfathered Choice Participants\".", "label": "Defined Contribution Plan Grandfathered Choice Participant [Member]", "terseLabel": "Defined contribution pension benefits - Grandfathered Choice Participant" } } }, "localname": "DefinedContributionPlanGrandfatheredChoiceParticipantMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "domainItemType" }, "pfg_Delaware2028TrustMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A Delaware statutory trust formed to serve as a source of liquidity for Principal Financial Group, Inc. (\"2028 Trust\").", "label": "Delaware2028 Trust [Member]", "terseLabel": "2028 Trust" } } }, "localname": "Delaware2028TrustMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_Delaware2048TrustMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A Delaware statutory trust formed to serve as a source of liquidity for Principal Financial Group, Inc. (\"2048 Trust\").", "label": "Delaware2048 Trust [Member]", "terseLabel": "2048 Trust" } } }, "localname": "Delaware2048TrustMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_DentalVisionShortTermDisabilityCriticalIllnessAccidentMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Product lines consisting of dental, vision, short-term disability, critical illness and accident insurance policies.", "label": "Dental Vision Short Term Disability Critical Illness Accident [Member]", "terseLabel": "Dental/Vision/Short-Term Disability/Critical Illness/Accident" } } }, "localname": "DentalVisionShortTermDisabilityCriticalIllnessAccidentMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "domainItemType" }, "pfg_DepositContractsLiabilitiesOther": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 4.0, "parentTag": "us-gaap_DepositContractsLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Carrying amount of liabilities as of the balance sheet date pertaining to amounts received by the insurer for investment contracts not otherwise specified in the taxonomy.", "label": "Deposit Contracts Liabilities Other", "terseLabel": "Other investment contracts" } } }, "localname": "DepositContractsLiabilitiesOther", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeAndHedgingRelatedAdjustments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 2.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Net impact to revenue of (1) adjustment for periodic settlements and accruals on derivatives not designated as hedging instruments to move that amount from net realized capital gains (losses) to net investment income for segment profit (loss) reporting, (2) adjustment for mark-to-market adjustments on derivatives and hedged items to move that amount from net investment income to net realized capital gains (losses) for segment profit (loss) reporting and (3) amortization of the cumulative fair value adjustment for assets that have had fair value hedge accounting terminated to move that amount from net investment income to net realized capital gains (losses) for segment profit (loss) reporting.", "label": "Derivative and Hedging-related Adjustments", "negatedLabel": "Derivative and hedging-related revenue adjustments" } } }, "localname": "DerivativeAndHedgingRelatedAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeCollateralPledged": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The carrying value as of the balance sheet date of the cash and securities pledged as collateral associated with derivative credit support agreements and Futures Commission Merchant agreements.", "label": "Derivative Collateral Pledged", "terseLabel": "Cash and securities posted under collateral arrangements associated with derivative credit support agreements and Futures Commission Merchant agreements" } } }, "localname": "DerivativeCollateralPledged", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeCollateralReceived": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails": { "order": 2.0, "parentTag": "pfg_DerivativeNetCreditExposure", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The carrying value as of the balance sheet date of the cash and securities received as collateral associated with derivative credit support agreements.", "label": "Derivative, Collateral Received", "terseLabel": "Less: collateral received" } } }, "localname": "DerivativeCollateralReceived", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeCreditExposure": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails": { "order": 1.0, "parentTag": "pfg_DerivativeNetCreditExposure", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount at risk if a counterparty to the derivative instruments does not perform.", "label": "Derivative Credit Exposure", "terseLabel": "Gross credit exposure" } } }, "localname": "DerivativeCreditExposure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeFairValueOfDerivativeLiabilityInvestmentAndUniversalLifeContracts": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 3.0, "parentTag": "us-gaap_LiabilitiesFairValueDisclosure", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the fair value of embedded derivatives that have been bifurcated from an investment host contract or universal life contract.", "label": "Derivative Fair Value of Derivative Liability Investment and Universal Life Contracts", "negatedLabel": "Investment and universal life contracts", "terseLabel": "Fair value of embedded derivative liabilities reported with contractholder funds" } } }, "localname": "DerivativeFairValueOfDerivativeLiabilityInvestmentAndUniversalLifeContracts", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangementExcludingEmbeddedDerivatives": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 1.0, "parentTag": "us-gaap_LiabilitiesFairValueDisclosure", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset. Excludes the fair value of embedded derivatives reported as investment contracts or other liabilities.", "label": "Derivative Liability Fair Value Gross Liability Including Not Subject to Master Netting Arrangement Excluding Embedded Derivatives", "negatedLabel": "Derivative liabilities" } } }, "localname": "DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangementExcludingEmbeddedDerivatives", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeNetCreditExposure": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount at risk if a counterparty to the derivative instrument does not perform, after considering collateral received.", "label": "Derivative, Net Credit Exposure", "totalLabel": "Net credit exposure" } } }, "localname": "DerivativeNetCreditExposure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DerivativeNotionalCreditExposureLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Derivative Notional Credit Exposure [Line Items]", "terseLabel": "Derivative Financial Instruments, exposure" } } }, "localname": "DerivativeNotionalCreditExposureLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "stringItemType" }, "pfg_DerivativeNotionalCreditExposureTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule that identifies notional amount and credit exposure information by type of derivative contract.", "label": "Derivative Notional Credit Exposure [Table]" } } }, "localname": "DerivativeNotionalCreditExposureTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "stringItemType" }, "pfg_DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The entire disclosure related to contingencies, guarantees, indemnifications and leases.", "label": "Disclosure of Contingencies, Guarantees, Indemnifications and Leases [Text Block ]", "terseLabel": "Contingencies, Guarantees, Indemnifications and Leases" } } }, "localname": "DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeases" ], "xbrltype": "textBlockItemType" }, "pfg_DisclosureOfLeaseQuantitativeAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Disclosure of Lease Quantitative [Abstract]", "terseLabel": "Weighted-average remaining lease term and weighted-average discount rates" } } }, "localname": "DisclosureOfLeaseQuantitativeAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "pfg_DiscountedCashFlowMortgageLoansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Discounted cash flow valuation technique used to measure fair value of mortgage loans.", "label": "Discounted Cash Flow Mortgage Loans [Member]", "terseLabel": "Discounted cash flow, mortgage loans" } } }, "localname": "DiscountedCashFlowMortgageLoansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_DiscountedCashFlowRealEstateDebtMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Discounted cash flow valuation technique used to measure fair value of real estate debt.", "label": "Discounted Cash Flow Real Estate Debt [Member]", "terseLabel": "Discounted cash flow, real estate debt" } } }, "localname": "DiscountedCashFlowRealEstateDebtMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_DiscountedCashFlowRealEstateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Discounted cash flow valuation technique used to measure fair value of real estate.", "label": "Discounted Cash Flow Real Estate [Member]", "terseLabel": "Discounted cash flow, real estate" } } }, "localname": "DiscountedCashFlowRealEstateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_DistributionsToRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Represents a decrease in redeemable noncontrolling interest from dividends or other distributions paid to redeemable noncontrolling interest holders.", "label": "Distributions to Redeemable Noncontrolling Interest", "negatedLabel": "Distributions to redeemable noncontrolling interest" } } }, "localname": "DistributionsToRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DividendRestrictionPercentageOfPolicyholdersSurplus": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the limitation on stockholder dividends as a percentage of the entity's statutory policyholder surplus as of the preceding year-end.", "label": "Dividend Restriction, Percentage of Policyholders Surplus", "terseLabel": "Dividend limitation as percentage of statutory policyholder surplus (as a percent)" } } }, "localname": "DividendRestrictionPercentageOfPolicyholdersSurplus", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "percentItemType" }, "pfg_DividendsReceivedFromContributionsToUnconsolidatedEntities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 10.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents disclosure of the amount of dividends, returns of capital or other distributions received from or contributions made to unconsolidated subsidiaries accounted for using the equity method of accounting.", "label": "Dividends Received from Contributions to Unconsolidated Entities", "terseLabel": "Dividends and returns of capital received from (contributed to) unconsolidated entities" } } }, "localname": "DividendsReceivedFromContributionsToUnconsolidatedEntities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_DividendsReceivedFromContributionsToUnconsolidatedEntitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Dividends Received from (Contributions to) Unconsolidated Entities [Abstract]", "terseLabel": "Dividends and Returns of Capital Received from (Contributed to) Unconsolidated Entity" } } }, "localname": "DividendsReceivedFromContributionsToUnconsolidatedEntitiesAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "stringItemType" }, "pfg_DocumentAndEntityInformationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Document and Entity Information" } } }, "localname": "DocumentAndEntityInformationAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_EarningsPerShareCalculationSubtractAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Subtract:" } } }, "localname": "EarningsPerShareCalculationSubtractAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "stringItemType" }, "pfg_EastNorthCentralMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the East North Central region of the United States.", "label": "East North Central [Member]", "terseLabel": "East North Central" } } }, "localname": "EastNorthCentralMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_EastSouthCentralMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the East South Central region of the United States.", "label": "East South Central [Member]", "terseLabel": "East South Central" } } }, "localname": "EastSouthCentralMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_EffectiveIncomeTaxRateReconciliationLocalCountryPermanentTaxAdjustmentsPercent": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 8.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to local country permanent tax adjustments.", "label": "Effective Income Tax Rate Reconciliation, Local Country Permanent Tax Adjustments, Percent", "terseLabel": "Local country permanent tax adjustments (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationLocalCountryPermanentTaxAdjustmentsPercent", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "pfg_EmployeePurchasePriceAsPercentOfFairMarketValue": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The specified percentage of the shares' fair market value as of the beginning or end of the contribution period at which employees may purchase shares of company common stock.", "label": "Employee Purchase Price as Percent of Fair Market Value", "terseLabel": "Employee purchase price as a percent of fair market value (as a percent)" } } }, "localname": "EmployeePurchasePriceAsPercentOfFairMarketValue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "percentItemType" }, "pfg_EmployeeStockOwnershipPlanESOPEarnedAndUnearnedDeferredSharesFairValue": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of earned and unearned shares held by the employee stock ownership plan (ESOP).", "label": "Employee Stock Ownership Plan E S O P Earned And Unearned Deferred Shares Fair Value", "terseLabel": "Fair value of employee stock ownership plan" } } }, "localname": "EmployeeStockOwnershipPlanESOPEarnedAndUnearnedDeferredSharesFairValue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "monetaryItemType" }, "pfg_EmployeeStockPurchasePlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A plan under which employees of the corporation can purchase the corporation's stock.", "label": "Employee Stock Purchase Plan [Member]", "terseLabel": "Employee Stock Purchase Plan" } } }, "localname": "EmployeeStockPurchasePlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "domainItemType" }, "pfg_EmployeeStockPurchasePlanSharesAvailableForIssuanceUnderPlan": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The difference between the maximum number of shares authorized for issuance under the Employee Stock Purchase Plan (including the effects of amendments) and the number of shares already issued under the plan, net of adjustments.", "label": "Employee Stock Purchase Plan, Shares Available for Issuance Under Plan", "terseLabel": "Shares available to be issued under employee stock purchase plan (in shares)" } } }, "localname": "EmployeeStockPurchasePlanSharesAvailableForIssuanceUnderPlan", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "sharesItemType" }, "pfg_EmployeeStockPurchasePlanWeightedAverageFairValueOfDiscount": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The weighted-average fair value per share of the discount applied to employee purchases under the employee stock purchase plan during the period.", "label": "Employee Stock Purchase Plan, Weighted Average, Fair Value of Discount", "terseLabel": "Weighted-average fair value of discount on employee stock purchase plan (in dollars per share)" } } }, "localname": "EmployeeStockPurchasePlanWeightedAverageFairValueOfDiscount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "perShareItemType" }, "pfg_EntityParentAndSubsidiariesNotesGuarantorDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "All parent companies and/or subsidiaries reported by a business entity when a parent guarantees notes issued by a subsidiary.", "label": "Entity Parent And Subsidiaries Notes Guarantor [Domain]", "terseLabel": "Entity, Parent and Subsidiaries - Notes Guarantor [Domain]" } } }, "localname": "EntityParentAndSubsidiariesNotesGuarantorDomain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_EntityShelfRegistrationDebtGuarantorDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "All parent companies and/or subsidiaries reported by a business entity when a subsidiary guarantees obligations of its parent.", "label": "Entity Shelf Registration Debt Guarantor [Domain]", "terseLabel": "Entity, Shelf Registration Debt Guarantor [Domain]" } } }, "localname": "EntityShelfRegistrationDebtGuarantorDomain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "domainItemType" }, "pfg_EquityMethodInvestmentSummarizedFinancialInformationProportionateShareOfNetIncomeLoss": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied.", "label": "Equity Method Investment Summarized Financial Information Proportionate Share Of Net Income Loss", "terseLabel": "Our share of net income of unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationProportionateShareOfNetIncomeLoss", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_EquityMethodInvestmentsRelatedAdjustments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 4.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in net investment income to net realized capital gains (losses) for segment profit (loss) reporting related to equity method investments.", "label": "Equity Method Investments Related Adjustments", "terseLabel": "Adjustments related to equity method investments" } } }, "localname": "EquityMethodInvestmentsRelatedAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_EquitySecuritiesAvailableForSaleRealizedGain": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 6.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Equity Securities, Available-for-sale, Realized Gain", "verboseLabel": "Equity securities, available-for-sale: Gross gains" } } }, "localname": "EquitySecuritiesAvailableForSaleRealizedGain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_EquitySecuritiesTradingRealizedGainLoss": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 7.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (trading).", "label": "Equity Securities, Trading, Realized Gain (Loss)", "terseLabel": "Equity securities, trading" } } }, "localname": "EquitySecuritiesTradingRealizedGainLoss", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_EquitySecuritiesTradingUnrealizedGainLoss": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (trading).", "label": "Equity Securities, Trading, Unrealized Gain (Loss)", "terseLabel": "Unrealized gains (losses) on equity securities, trading" } } }, "localname": "EquitySecuritiesTradingUnrealizedGainLoss", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ExcessCarryingValueOverTaxBasisWithoutDeferredTaxesProvided": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Excess book carrying value over tax basis with respect to the original investment of foreign subsidiaries for which it is not practical to determine the amount of unrecognized deferred tax liability.", "label": "Excess Carrying Value over Tax Basis, Without Deferred Taxes Provided", "terseLabel": "Excess book carrying value over tax basis with respect to the original investment of foreign subsidiaries for which U.S. federal and state deferred income taxes have not been provided" } } }, "localname": "ExcessCarryingValueOverTaxBasisWithoutDeferredTaxesProvided", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ExercisePriceRange1Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the range of exercise prices in dollars per share from $X to X for purposes of disclosing outstanding stock option awards on all stock option plans and other required information pertaining to awards.", "label": "Exercise Price Range1 [Member]", "terseLabel": "Range of exercise prices, Range 1" } } }, "localname": "ExercisePriceRange1Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "pfg_ExercisePriceRange2Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the range of exercise prices in dollars per share from $X to X for purposes of disclosing outstanding stock option awards on all stock option plans and other required information pertaining to awards.", "label": "Exercise Price Range2 [Member]", "terseLabel": "Range of exercise prices, Range 2" } } }, "localname": "ExercisePriceRange2Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "pfg_ExercisePriceRange3Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the range of exercise prices in dollars per share from $X to X for purposes of disclosing outstanding stock option awards on all stock option plans and other required information pertaining to awards.", "label": "Exercise Price Range3 [Member]", "terseLabel": "Range of exercise prices, Range 3" } } }, "localname": "ExercisePriceRange3Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "pfg_ExercisePriceRange4Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the range of exercise prices in dollars per share from $X to X for purposes of disclosing outstanding stock option awards on all stock option plans and other required information pertaining to awards.", "label": "Exercise Price Range4 [Member]", "terseLabel": "Range of exercise prices, Range 4" } } }, "localname": "ExercisePriceRange4Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "pfg_ExercisePriceTotalRangeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the total range of exercise prices in dollars per share from $X to X for purposes of disclosing outstanding stock option awards on all stock option plans and other required information pertaining to awards.", "label": "Exercise Price Total Range [Member]", "terseLabel": "Range of exercise prices, Total Range" } } }, "localname": "ExercisePriceTotalRangeMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Fair Value Assets and Liabilities Measured on Recurring Basis Transfers [Line Items]", "terseLabel": "Fair Value Hierarchy Levels Transfers" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule of transfers of assets and liabilities measured at fair value on recurring basis between levels of the fair value hierarchy.", "label": "Fair Value, Assets and Liabilities Measured on Recurring Basis, Transfers [Table]" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]", "terseLabel": "Changes in Level 3 fair value measurements rollforward, assets and liabilities" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Summarization of information required and determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (Level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets and liabilities), and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets and liabilities) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of asset or liability.", "label": "Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table]" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueAssetsLevel1ToLevel2TransfersAmountDuration": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of assets measured on a recurring basis out of Level 1 into Level 2 of the fair value hierarchy.", "label": "Fair Value Assets Level 1 to Level 2 Transfers Amount Duration", "terseLabel": "Transfers out of Level 1 into Level 2" } } }, "localname": "FairValueAssetsLevel1ToLevel2TransfersAmountDuration", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsLevel2ToLevel1TransfersAmountDuration": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of assets measured on a recurring basis out of Level 2 into Level 1 of the fair value hierarchy.", "label": "Fair Value Assets Level 2 to Level 1 Transfers Amount Duration", "terseLabel": "Transfers out of Level 2 into Level 1" } } }, "localname": "FairValueAssetsLevel2ToLevel1TransfersAmountDuration", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsLevel2ToLevel3TransfersAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 3.", "label": "Fair Value Assets Level 2 to Level 3 Transfers, Amount", "terseLabel": "Transfers out of Level 2 into Level 3" } } }, "localname": "FairValueAssetsLevel2ToLevel3TransfersAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsLevel3ToLevel1TransfersAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of assets measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 1.", "label": "Fair Value Assets Level 3 to Level 1 Transfers, Amount", "terseLabel": "Transfers out of Level 3 into Level 1" } } }, "localname": "FairValueAssetsLevel3ToLevel1TransfersAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsLevel3ToLevel2TransfersAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of assets measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 2.", "label": "Fair Value, Level 3 to Level 2 Transfers, Amount", "terseLabel": "Transfers out of Level 3 into Level 2" } } }, "localname": "FairValueAssetsLevel3ToLevel2TransfersAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsMeasuredOnRecurringBasisCashEquivalents": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 6.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents short-term invested assets with a maturity date of three months or less when purchased that are required to be reported at fair value in the statement of financial position.", "label": "Fair Value Assets Measured on Recurring Basis Cash Equivalents", "terseLabel": "Cash equivalents" } } }, "localname": "FairValueAssetsMeasuredOnRecurringBasisCashEquivalents", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsMeasuredOnRecurringBasisOtherInvestments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 5.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents invested assets not specifically identified in the statement of financial position, excluding derivative assets, that are required to be reported at fair value in the statement of financial position. This includes invested assets such as seed money and commercial mortgage loans of consolidated variable interest entities reported at fair value.", "label": "Fair Value Assets Measured on Recurring Basis, Other Investments", "terseLabel": "Other investments" } } }, "localname": "FairValueAssetsMeasuredOnRecurringBasisOtherInvestments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 1.0, "parentTag": "us-gaap_AssetsFairValueDisclosure", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This element represents assets, other than separate account assets, measured at fair value on a recurring basis.", "label": "Fair Value Assets Measured on Recurring Basis, Total Assets Excluding Separate Account Assets", "totalLabel": "Sub-total excluding separate account assets" } } }, "localname": "FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueInputsAssetsLiabilitiesQuantitativeInformationLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Fair Value Inputs Assets (Liabilities) Quantitative Information [Line Items]", "terseLabel": "Unobservable inputs" } } }, "localname": "FairValueInputsAssetsLiabilitiesQuantitativeInformationLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueInputsQuantitativeInformationTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule of the inputs used in the fair value measurement of assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). This disclosure may include, but is not limited to, the fair value of the asset or liability, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs.", "label": "Fair Value, Assets and Liabilities Measured on Recurring Basis, Level 3 Quantitative Information [Table]" } } }, "localname": "FairValueInputsQuantitativeInformationTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesPurchasesSalesIssuancesSettlementsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Asset and Liabilities Purchases Sales Issuances Settlements [Abstract]", "terseLabel": "Gross purchases, sales, issuances and settlements" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesPurchasesSalesIssuancesSettlementsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsRelatingToPositionsStillHeld": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings relating to positions still held.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Relating to Positions Still Held", "terseLabel": "Changes in unrealized gains (losses) included in net income relating to positions still held, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsRelatingToPositionsStillHeld", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIssuesNet": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 1.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchasesSalesIssuancesSettlements", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of net issuances of financial instruments measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Issues, Net", "negatedLabel": "Issuances, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIssuesNet", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This element represents total gains or losses for the period (realized and unrealized), arising from liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings relating to positions still held.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liabilities, Gain (Loss) Included in Earnings Relating to Positions Still Held", "terseLabel": "Changes in unrealized gains (losses) included in net income relating to positions still held, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetDerivativeAssetsGainLossIncludedInEarningsRelatingToPositionsStillHeld": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This element represents total gains or losses for the period (realized and unrealized), arising from net derivatives assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings relating to positions still held.", "label": "Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Net Derivative Assets Gain Loss Included in Earnings Relating to Positions Still Held", "terseLabel": "Changes in unrealized gains (losses) included in net income relating to positions still held, net derivative assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetDerivativeAssetsGainLossIncludedInEarningsRelatingToPositionsStillHeld", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueOptionContractualPrincipalAmountsOfAssetsForWhichFairValueOptionWasElected": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The contractual principal amounts of commercial mortgage loans of consolidated variable interest entities for which the fair value option was elected.", "label": "Fair Value Option, Contractual Principal Amounts of Assets for Which Fair Value Option was Elected", "terseLabel": "Contractual principal amounts of assets for which the fair value option was elected" } } }, "localname": "FairValueOptionContractualPrincipalAmountsOfAssetsForWhichFairValueOptionWasElected", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueOptionCreditRiskGainsLossesLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of gains and losses from fair value changes included in earnings that are attributable to changes in the instrument-specific credit risk of liabilities.", "label": "Fair Value Option, Credit Risk (Gains) Losses, Liabilities", "negatedLabel": "Credit risk portion of pre-tax gain (loss) due to change in fair value of liabilities for which the fair value option was elected" } } }, "localname": "FairValueOptionCreditRiskGainsLossesLiabilities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The fair value of commercial mortgage loans of consolidated variable interest entities and equity method investments for which the fair value option was elected.", "label": "Fair Value Option, Fair Value of Assets for Which Fair Value Option Was Elected", "terseLabel": "Fair value of assets for which fair value option was elected" } } }, "localname": "FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FairValueTransfersTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of transfers between Level 1, Level 2 and Level 3 of the fair value hierarchy for assets and liabilities measured at fair value on a recurring basis.", "label": "Fair Value Transfers [Table Text Block]", "terseLabel": "Transfers (Table)" } } }, "localname": "FairValueTransfersTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "pfg_FeesAndOtherRevenuesNotWithinScopeOfRevenueRecognitionGuidance": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails": { "order": 3.0, "parentTag": "pfg_InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of fees and commissions from financial services and banking activities and correspondent clearing, excluding contracts with customers and other pre-tax adjustments.", "label": "Fees and Other Revenues Not Within the Scope of Revenue Recognition Guidance", "terseLabel": "Fees and other revenues not within the scope of revenue recognition guidance", "verboseLabel": "Fees and other revenues not within the scope of revenue recognition guidance" } } }, "localname": "FeesAndOtherRevenuesNotWithinScopeOfRevenueRecognitionGuidance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FinancialAssetTypeAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by type of financial asset.", "label": "Financial Asset Type [Axis]" } } }, "localname": "FinancialAssetTypeAxis", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "stringItemType" }, "pfg_FinancialAssetTypeCategorizationDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Categorization of financial assets by asset type.", "label": "Financial Asset Type Categorization [Domain]", "terseLabel": "Financial Asset Type Categorization [Domain]" } } }, "localname": "FinancialAssetTypeCategorizationDomain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_FinancialInstrumentsNotReportedAtFairValueLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Financial Instruments Not Reported at Fair Value [Line Items]", "verboseLabel": "Carrying value and estimated fair value of financial instruments, financial statement captions" } } }, "localname": "FinancialInstrumentsNotReportedAtFairValueLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "stringItemType" }, "pfg_FinancialInstrumentsNotReportedAtFairValueTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined) that are not measured at fair value on a recurring basis. Such disclosures about the financial instruments include the fair value of the required items together with their carrying amounts (as appropriate). The fair value measurements at the reporting date also include the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).", "label": "Schedule of Financial Instruments Not Reported at Fair Value [Table]" } } }, "localname": "FinancialInstrumentsNotReportedAtFairValueTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "stringItemType" }, "pfg_FinancialInstrumentsNotReportedAtValueTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined) that are not measured at fair value on a recurring basis. Such disclosures about the financial instruments include the fair value of the required items together with their carrying amounts (as appropriate). The fair value measurements at the reporting date also include the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).", "label": "Financial Instruments Not Reported at Value [Table Text Block]", "terseLabel": "Financial Instruments Not Reported at Fair Value (Table)" } } }, "localname": "FinancialInstrumentsNotReportedAtValueTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "pfg_FinancialLiabilityTypeAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by type of financial liability.", "label": "Financial Liability Type [Axis]" } } }, "localname": "FinancialLiabilityTypeAxis", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "pfg_FinancialLiabilityTypeCategorizationDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Categorization of financial liabilities by liability type.", "label": "Financial Liability Type Categorization [Domain]", "terseLabel": "Financial Liability Type Categorization [Domain]" } } }, "localname": "FinancialLiabilityTypeCategorizationDomain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "pfg_FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A description of the remaining amortization period of finite-lived intangible assets.", "label": "Finite Lived Intangible Assets, Weighted Average Remaining Expected Life", "terseLabel": "Weighted average remaining expected life of finite lived intangible assets" } } }, "localname": "FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "durationItemType" }, "pfg_FixedMaturitiesPledgedAsCollateral": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of fixed maturity securities that have been pledged as collateral for a reinsurance arrangement, derivative credit support annex agreements, Futures Commission Merchant agreements, a lending arrangement and an obligation under funding agreements with Federal Home Loan Bank of Des Moines.", "label": "Fixed Maturities Pledged as Collateral", "terseLabel": "Fixed maturities available-for-sale and trading securities posted as collateral for a reinsurance arrangement, derivative credit support annex (collateral) agreements, Futures Commission Merchant agreements, a lending arrangement and an obligation under funding agreements with Federal Home Loan Bank of Des Moines" } } }, "localname": "FixedMaturitiesPledgedAsCollateral", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsSecuritiesPostedAsCollateralDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FixedMaturitiesSecuritiesAvailableForSaleMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.", "label": "Fixed Maturities Securities Available For Sale [Member]", "terseLabel": "Fixed maturities, available-for-sale" } } }, "localname": "FixedMaturitiesSecuritiesAvailableForSaleMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "domainItemType" }, "pfg_FixedMaturitySecuritiesLevel3ValuedUsingInternalPricingModels": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The percentage of fixed maturity securities classified as Level 3 that were valued using internal pricing models.", "label": "Fixed Maturity Securities, Level 3 Valued Using Internal Pricing Model, Percent", "terseLabel": "Fixed maturities classified as Level 3 assets, percent valued using internal pricing models (as a percent)" } } }, "localname": "FixedMaturitySecuritiesLevel3ValuedUsingInternalPricingModels", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "percentItemType" }, "pfg_FixedMaturitySecuritiesValuedUsingInternalPricingModelsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Fixed maturities valued using internal pricing models", "terseLabel": "Fixed maturities valued using internal pricing models" } } }, "localname": "FixedMaturitySecuritiesValuedUsingInternalPricingModelsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "stringItemType" }, "pfg_FrontEndFeeRevenuesRecognition": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 6.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in fees and other revenues to net realized capital gains (losses) for segment profit (loss) reporting related to amortization of unearned revenue reserves attributable to the portion of estimated gross profits related to net realized capital gains (losses).", "label": "Front-End Fee Revenues, Recognition", "terseLabel": "Recognition of front-end fee revenue" } } }, "localname": "FrontEndFeeRevenuesRecognition", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FundingAgreement1998ProgramMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreement program established in 1998 to support the prospective issuance of medium term notes by an unaffiliated entity in non-U.S. markets.", "label": "Funding Agreement1998 Program [Member]", "terseLabel": "1998 Funding agreement program" } } }, "localname": "FundingAgreement1998ProgramMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreement2001ProgramMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreement program established in 2001 to support the prospective issuance of medium term notes by an unaffiliated entity in both domestic and international markets.", "label": "Funding Agreement2001 Program [Member]", "terseLabel": "2001 Funding agreement program" } } }, "localname": "FundingAgreement2001ProgramMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreement2004ProgramMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreement program established in 2004 to support the prospective issuance of medium term notes by unaffiliated entities in both domestic and international markets.", "label": "Funding Agreement2004 Program [Member]", "terseLabel": "2004 Funding agreement program" } } }, "localname": "FundingAgreement2004ProgramMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreement2006ProgramMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreement program established in 2006 to support the prospective issuance of medium term notes by an unaffiliated entity in non-U.S. markets.", "label": "Funding Agreement2006 Program [Member]", "terseLabel": "2006 Funding agreement program" } } }, "localname": "FundingAgreement2006ProgramMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreement2011ProgramMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreement program established in 2011 to support the prospective issuance of medium term notes by an unaffiliated entity in both domestic and international markets.", "label": "Funding Agreement2011 Program [Member]", "terseLabel": "2011 Funding agreement program" } } }, "localname": "FundingAgreement2011ProgramMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreementAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Categorization of funding agreements by program.", "label": "Funding Agreement [Axis]" } } }, "localname": "FundingAgreementAxis", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FundingAgreementDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Separate programs established for issuance of funding agreements to unconsolidated special purpose entities.", "label": "Funding Agreement [Domain]", "terseLabel": "Funding Agreement [Domain]" } } }, "localname": "FundingAgreementDomain", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreementLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Funding Agreement [Line Items]", "terseLabel": "Funding agreement disclosures" } } }, "localname": "FundingAgreementLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FundingAgreementTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Summarization of information related to different funding agreement authorizations.", "label": "Funding Agreement [Table]" } } }, "localname": "FundingAgreementTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "stringItemType" }, "pfg_FundingAgreements": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 3.0, "parentTag": "us-gaap_DepositContractsLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of the liability as of the balance sheet date pertaining to amounts received by the insurer for funding agreements.", "label": "Funding Agreements", "terseLabel": "Funding agreements" } } }, "localname": "FundingAgreements", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FundingAgreementsAuthorizationUtilized": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Portion of the total amount authorized under a funding agreement program that has been utilized or nearly utilized.", "label": "Funding Agreements Authorization Utilized", "terseLabel": "Amount of funding agreement authorization used at time additional amount authorized" } } }, "localname": "FundingAgreementsAuthorizationUtilized", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FundingAgreementsAuthorizedAmountAdditionalMaximum": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Additional maximum amount authorized for issuance under an existing funding agreement program.", "label": "Funding Agreements Authorized Amount Additional Maximum", "terseLabel": "Additional maximum authorized amount of funding agreements to be issued" } } }, "localname": "FundingAgreementsAuthorizedAmountAdditionalMaximum", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FundingAgreementsAuthorizedAmountMaximum": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Maximum amount authorized for issuance under a funding agreement program.", "label": "Funding Agreements Authorized Amount Maximum", "terseLabel": "Maximum authorized amount of funding agreements to be issued" } } }, "localname": "FundingAgreementsAuthorizedAmountMaximum", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_FundingAgreementsFederalHomeLoanBankDesMoinesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Funding agreements issued to the Federal Home Loan Bank of Des Moines under their membership funding programs.", "label": "Funding Agreements Federal Home Loan Bank Des Moines [Member]", "terseLabel": "FHLB Des Moines funding agreement program" } } }, "localname": "FundingAgreementsFederalHomeLoanBankDesMoinesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_FundingAgreementsProgramsNotGuaranteedByPFG": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The number of funding agreement-backed medium term note programs under which Principal Life's payment obligations are not guaranteed by PFG.", "label": "Funding Agreements Programs Not Guaranteed By PFG", "terseLabel": "Number of funding agreement programs not guaranteed by PFG" } } }, "localname": "FundingAgreementsProgramsNotGuaranteedByPFG", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "integerItemType" }, "pfg_FundingAgreementsProgramsNumber": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The number of programs established to authorize the issuance of funding agreements to support the prospective issuance of medium term notes by unconsolidated special purpose entities.", "label": "Funding Agreements Programs Number", "terseLabel": "Number of separate funding agreement programs" } } }, "localname": "FundingAgreementsProgramsNumber", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails" ], "xbrltype": "integerItemType" }, "pfg_GainLossOnInvestmentsStatementOfOperationsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of realized and unrealized gain (loss) on investment in security reported in the statement of operations.", "label": "Gain (Loss) on Investments, Statement of Operations [Table Text Block]", "terseLabel": "Net Realized Capital Gains and Losses (Table)" } } }, "localname": "GainLossOnInvestmentsStatementOfOperationsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_GovernmentDebtMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This category includes information about debt that is issued by a government or municipal agency.", "label": "Government Debt [Member]", "terseLabel": "Government/municipalities" } } }, "localname": "GovernmentDebtMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "pfg_GrossAmountAssetsNotSubjectToNetting": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial assets (reverse repurchase agreements and securities lending transactions) not subject to master netting agreements or similar agreements.", "label": "Gross Amount Assets Not Subject to Netting", "terseLabel": "Gross amount of assets not subject to netting agreements" } } }, "localname": "GrossAmountAssetsNotSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossAmountLiabilitiesNotSubjectToNetting": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial liabilities (repurchase agreements and securities borrowing transactions) not subject to master netting agreements or similar agreements.", "label": "Gross Amount Liabilities Not Subject to Netting", "terseLabel": "Gross amount of liabilities not subject to netting agreements" } } }, "localname": "GrossAmountLiabilitiesNotSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossAmountRecognizedAssetsSubjectToNetting": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails": { "order": 1.0, "parentTag": "pfg_NetAmountAssetsSubjectToNetting", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial assets (reverse repurchase agreements and securities lending transactions) subject to master netting agreements or similar agreements.", "label": "Gross Amount Recognized Assets Subject to Netting", "terseLabel": "Gross amount of recognized assets subject to netting agreements" } } }, "localname": "GrossAmountRecognizedAssetsSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossAmountRecognizedAssetsSubjectToNettingNotOffset": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails": { "order": 2.0, "parentTag": "pfg_NetAmountAssetsSubjectToNetting", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Value of financial liabilities that offset derivative and other financial assets (reverse repurchase agreements and securities lending transactions) subject to master netting agreements or similar agreements, elected not to be offset in the statement of financial position.", "label": "Gross Amount Recognized Assets Subject to Netting Not Off set", "negatedLabel": "Amount of liabilities that offset the gross amount of assets subject to netting agreements not offset in statement of financial position" } } }, "localname": "GrossAmountRecognizedAssetsSubjectToNettingNotOffset", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossAmountRecognizedLiabilitiesSubjectToNetting": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails": { "order": 1.0, "parentTag": "pfg_NetAmountLiabilitiesSubjectToNetting", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial liabilities (repurchase agreements and securities borrowing transactions) subject to master netting agreements or similar agreements.", "label": "Gross Amount Recognized Liabilities Subject to Netting", "terseLabel": "Gross amount of recognized liabilities subject to netting agreements" } } }, "localname": "GrossAmountRecognizedLiabilitiesSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossAmountRecognizedLiabilitiesSubjectToNettingNotOffset": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails": { "order": 2.0, "parentTag": "pfg_NetAmountLiabilitiesSubjectToNetting", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Value of financial assets that offset derivative and other financial liabilities (repurchase agreements and securities borrowing transactions) subject to master netting agreements or similar agreements, elected not to be offset in the statement of financial position.", "label": "Gross Amount Recognized Liabilities Subject to Netting Not Offset", "negatedLabel": "Amount of assets that offset the gross amount of liabilities subject to netting agreements not offset in statement of financial position" } } }, "localname": "GrossAmountRecognizedLiabilitiesSubjectToNettingNotOffset", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GrossInvestmentIncomeLoss": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails": { "order": 1.0, "parentTag": "us-gaap_NetInvestmentIncome", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Income derived from investments and on cash and cash equivalents, net of amortization of purchase discounts and premiums related to investments in debt securities. Interest income represents earnings which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Dividend income represents a distribution of earnings to shareholders by investee companies. The purchase discount or premium is amortized to income or expense, respectively, over the life (holding period) of the securities to arrive at an amount of periodic interest income or expense which results in a constant effective yield on the investments.", "label": "Gross Investment Income (Loss)", "terseLabel": "Gross investment income (loss)" } } }, "localname": "GrossInvestmentIncomeLoss", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "monetaryItemType" }, "pfg_GroupLifeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Product line consisting of life insurance policies issued to organizations to provide benefits to multiple individuals.", "label": "Group Life [Member]", "terseLabel": "Group Life" } } }, "localname": "GroupLifeMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "domainItemType" }, "pfg_GuaranteesToThirdPartiesPrimarilyRelatedToFormerSubsidiariesAndJointVenturesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Guarantees provided by the entity to third parties, primarily related to former subsidiaries and joint ventures.", "label": "Guarantees To Third Parties Primarily Related To Former Subsidiaries And Joint Ventures [Member]", "terseLabel": "Guarantees to third parties primarily related to former subsidiaries and joint ventures" } } }, "localname": "GuaranteesToThirdPartiesPrimarilyRelatedToFormerSubsidiariesAndJointVenturesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "domainItemType" }, "pfg_GuaranteesToUnconsolidatedTrustsUnderContingentFundingAgreementsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "In connection with pre-capitalization trust securities contingent funding agreements, the requirement to purchase any principal and interest strips of U.S. Treasury securities that are due and not paid from the associated unconsolidated trusts.", "label": "Guarantees To Unconsolidated Trusts Under Contingent Funding Agreements [Member]", "terseLabel": "Guarantees related to P-Caps contingent funding agreements" } } }, "localname": "GuaranteesToUnconsolidatedTrustsUnderContingentFundingAgreementsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "domainItemType" }, "pfg_GuarantyFundsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Guaranty Funds [Abstract]", "terseLabel": "Guaranty Funds" } } }, "localname": "GuarantyFundsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "pfg_HedgedAssetDiscontinuedFairValueHedge": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": 1.0, "parentTag": "pfg_HedgedAssetFairValueHedgeIncludingDiscontinued", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset previously hedged in a fair value hedging relationship that has been discontinued.", "label": "Hedged Asset, Discontinued Fair Value Hedge", "terseLabel": "Amortized cost of hedged item - Discontinued hedging relationships" } } }, "localname": "HedgedAssetDiscontinuedFairValueHedge", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_HedgedAssetFairValueHedgeIncludingDiscontinued": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset hedged in fair value hedging relationship or previously hedged in a fair value hedging relationship that has been discontinued.", "label": "Hedged Asset, Fair Value Hedge Including Discontinued", "totalLabel": "Amortized cost of hedged item - Active or discontinued hedging relationships" } } }, "localname": "HedgedAssetFairValueHedgeIncludingDiscontinued", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk, including amount remaining after discontinued hedge.", "label": "Hedged Asset, Fair Value Hedge Including Discontinued, Cumulative Increase (Decrease)", "totalLabel": "Cumulative amount of fair value hedging basis adjustment - Active or discontinued hedging relationships" } } }, "localname": "HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_HomeOfficeMedicalAndLifePlansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A postretirement benefit plan that specifically covers medical and life insurance costs for home office employees.", "label": "Home Office Medical And Life Plans [Member]", "terseLabel": "Home office medical and life plans" } } }, "localname": "HomeOfficeMedicalAndLifePlansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_ProfitLoss", "weight": 1.0 }, "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_NetIncomeLoss", "weight": 1.0 }, "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The sum of income (expense), including income (expense) attributable to the noncontrolling interest, before income taxes for continuing operations.", "label": "Income (Loss) from Continuing Operations before Income Taxes", "terseLabel": "Loss before income taxes", "totalLabel": "Income (loss) before income taxes", "verboseLabel": "Income (loss) before income taxes" } } }, "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "pfg_IncomeTaxAuthorityLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in the table.", "label": "Income Tax Authority [Line Items]", "verboseLabel": "Income Taxes" } } }, "localname": "IncomeTaxAuthorityLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "pfg_IncomeTaxAuthorityTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule reflecting pertinent information, such as tax authority, deferred tax asset and liability amounts as well as information related to operating loss carryforwards (amounts and expiration dates).", "label": "Income Tax Authority [Table]" } } }, "localname": "IncomeTaxAuthorityTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "pfg_IncreaseDecreaseInIncomeTaxExpenseAdjustmentsToDeferredTaxAssetsAndLiabilities": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of increase decrease in income tax expense adjustments to deferred tax assets and liabilities.", "label": "Increase Decrease In Income Tax Expense Adjustments To Deferred Tax Assets And Liabilities", "terseLabel": "Adjustments to deferred tax assets and liabilities" } } }, "localname": "IncreaseDecreaseInIncomeTaxExpenseAdjustmentsToDeferredTaxAssetsAndLiabilities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_IncreaseDecreaseInRedeemableNoncontrollingInterestRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Increase (Decrease) in Redeemable Noncontrolling Interest [Roll Forward]", "terseLabel": "Change in redeemable noncontrolling interest rollforward" } } }, "localname": "IncreaseDecreaseInRedeemableNoncontrollingInterestRollForward", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "stringItemType" }, "pfg_IncreaseDecreaseInSharesOutstandingRollforward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Increase (Decrease) in Shares Outstanding [Rollforward]", "terseLabel": "Reconciliation of Outstanding Common Shares" } } }, "localname": "IncreaseDecreaseInSharesOutstandingRollforward", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "stringItemType" }, "pfg_IncreaseInOtherInvestmentsDueToDiscontinuingEquityMethodAccounting": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Increase in other investments due to discontinuing equity method accounting for certain real estate joint ventures.", "label": "Increase in Other Investments Due to Discontinuing Equity Method Accounting", "terseLabel": "Increase in other investments due to discontinuing equity method accounting" } } }, "localname": "IncreaseInOtherInvestmentsDueToDiscontinuingEquityMethodAccounting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_InstitutionalRetirementAndTrustBusinessOfWellsFargoBankMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the information pertaining to Institutional Retirement and Trust business of Wells Fargo Bank.", "label": "Institutional Retirement And Trust Business Of Wells Fargo Bank [Member]", "terseLabel": "Institutional Retirement & Trust business of Wells Fargo Bank" } } }, "localname": "InstitutionalRetirementAndTrustBusinessOfWellsFargoBankMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "domainItemType" }, "pfg_InsuranceLiabilitiesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Insurance Liabilities" } } }, "localname": "InsuranceLiabilitiesDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_InsuranceLiabilitiesDisclosureTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The entire disclosure related to contractholder funds and future policy benefits and claims.", "label": "Insurance Liabilities Disclosure [Text Block]", "terseLabel": "Insurance Liabilities" } } }, "localname": "InsuranceLiabilitiesDisclosureTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilities" ], "xbrltype": "textBlockItemType" }, "pfg_InterSegmentRevenue": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of revenue resulting from transactions with other operating segments of the same entity.", "label": "Inter-segment Revenue", "terseLabel": "Inter-segment revenues" } } }, "localname": "InterSegmentRevenue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InterestRateDerivativesCashExchanged": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Represents the amount of cash exchanged under the interest rate derivative contracts.", "label": "Interest Rate Derivatives Cash Exchanged", "terseLabel": "Cash exchanged under contract" } } }, "localname": "InterestRateDerivativesCashExchanged", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InterestRateDerivativesPrincipalPayments": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents the amount of principal payments made by parties to the interest rate derivative contracts.", "label": "Interest Rate Derivatives Principal Payments", "terseLabel": "Principal payments made under contract" } } }, "localname": "InterestRateDerivativesPrincipalPayments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InterestRateFutureMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Forward-based contracts to purchase or sell a specified number of contracts at a specified future date or during a specified period at a specified yield.", "label": "Interest Rate Future [Member]", "terseLabel": "Interest rate futures" } } }, "localname": "InterestRateFutureMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "pfg_InterestRateOptionsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Interest rate options are forward-based contracts that combine interest rate caps and interest rate floors and entitle the purchaser to pay or receive the amounts, if any, by which a specified market rate exceeds a cap strike interest rate or falls below a floor strike interest rate, respectively, at specified dates.", "label": "Interest Rate Options [Member]", "terseLabel": "Interest rate options" } } }, "localname": "InterestRateOptionsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "pfg_InternationalMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents International regions outside of the United States.", "label": "International [Member]", "terseLabel": "International" } } }, "localname": "InternationalMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_IntrinsicValueFromAwardsOrUnitsVested": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The total accumulated difference between fair values of underlying shares on dates of vesting and exercise price on awards or units which were vested during the reporting period under the plan.", "label": "Intrinsic Value From Awards or Units Vested", "terseLabel": "Intrinsic value from awards or units vested" } } }, "localname": "IntrinsicValueFromAwardsOrUnitsVested", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_IntrinsicValueFromSharesSettled": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The total accumulated difference between the fair value of underlying shares on the last day of the contribution period and the price employees pay for the shares issued for the contribution period.", "label": "Intrinsic Value From Shares Settled", "terseLabel": "Intrinsic value from shares settled" } } }, "localname": "IntrinsicValueFromSharesSettled", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 }, "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails": { "order": 1.0, "parentTag": "pfg_OperatingRevenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of fees and commissions related to financial service activities including, but not limited to, investment advisory and asset management services, recordkeeping and reporting services, administrative activities and sales of insurance and related services.", "label": "Investment Advisory, Asset Management and Insurance Fees and Commissions", "terseLabel": "Fees and other revenues", "totalLabel": "Total fees and other revenues per consolidated statements of operations", "verboseLabel": "Total fees and other revenues" } } }, "localname": "InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "pfg_InvestmentAndUniversalLifeContractsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Embedded derivatives that have been bifurcated from an investment or universal life contract.", "label": "Investment And Universal Life Contracts [Member]", "terseLabel": "Investment and universal life contracts" } } }, "localname": "InvestmentAndUniversalLifeContractsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_InvestmentContractMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Embedded derivatives that have been bifurcated from an investment host contract.", "label": "Investment Contract [Member]", "terseLabel": "Investment contracts" } } }, "localname": "InvestmentContractMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_InvestmentContractsFairValueDisclosure": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents investment contracts such as guaranteed investment contracts and funding arrangements that do not have significant insurance risk. This item excludes any embedded derivatives within investment host contracts that are required to be reported at fair value.", "label": "Investment Contracts, Fair Value Disclosure", "negatedLabel": "Investment contracts" } } }, "localname": "InvestmentContractsFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InvestmentGainsAndLossesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Investment Gains and Losses [Line Items]" } } }, "localname": "InvestmentGainsAndLossesLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails" ], "xbrltype": "stringItemType" }, "pfg_InvestmentsDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Investments" } } }, "localname": "InvestmentsDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_InvestmentsDisclosureTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The entire disclosure related to Investments in the following: 1) Fixed Maturities and Equity Securities, 2) Mortgage Loans, 3) Real Estate, and 4) Other Investments. Fixed Maturities and Equity Securities and Mortgage Loans are included in quarterly disclosures. Other types of investments are only included in annual disclosures.", "label": "Investments Disclosure [Text Block]", "terseLabel": "Investments" } } }, "localname": "InvestmentsDisclosureTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestments" ], "xbrltype": "textBlockItemType" }, "pfg_InvestmentsInRealEstate": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Investments in real estate held for investment purposes and held-for-sale.", "label": "Investments in Real Estate", "terseLabel": "Real estate" } } }, "localname": "InvestmentsInRealEstate", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails" ], "xbrltype": "monetaryItemType" }, "pfg_InvestmentsInRealEstateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Investments in real estate held for investment purposes and held-for-sale.", "label": "Investments In Real Estate [Member]", "terseLabel": "Real estate" } } }, "localname": "InvestmentsInRealEstateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "domainItemType" }, "pfg_InvestmentsOtherMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Invested assets not specifically identified in the statement of financial position, excluding derivative assets, that are required to be reported at fair value in the statement of financial position. This includes invested assets such as seed money, commercial mortgage loans of consolidated variable interest entities, and equity method investments reported at fair value.", "label": "Investments Other [Member]", "terseLabel": "Other investments" } } }, "localname": "InvestmentsOtherMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "domainItemType" }, "pfg_LawsuitAllegingBreachOfFiduciaryDutyInConnectionWithPrincipalFixedIncomeOptionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Lawsuit filed on November 12, 2014, alleging breach of fiduciary duties and engaging in prohibited transactions under ERISA in connection with a general account guaranteed product known as the Principal Fixed Income Option (\"PFIO\").", "label": "Lawsuit Alleging Breach Of Fiduciary Duty In Connection With Principal Fixed Income Option [Member]", "terseLabel": "Lawsuit alleging breach of fiduciary duty related to PFIO" } } }, "localname": "LawsuitAllegingBreachOfFiduciaryDutyInConnectionWithPrincipalFixedIncomeOptionMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "domainItemType" }, "pfg_LeaseAssetsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Lease Assets [Abstract]", "terseLabel": "Assets" } } }, "localname": "LeaseAssetsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "pfg_LeaseAssetsEstablishedUponAdoptionOfAccountingGuidance": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of non-cash activity related to lease assets established upon adoption of accounting guidance.", "label": "Lease Assets Established upon Adoption of Accounting Guidance", "terseLabel": "Lease assets established upon adoption of accounting guidance" } } }, "localname": "LeaseAssetsEstablishedUponAdoptionOfAccountingGuidance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseBalanceSheetDisclosureTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of lease assets and liabilities for lessee.", "label": "Lease Balance Sheet Disclosure [Table Text Block]", "terseLabel": "Lease Assets and Liabilities (Table)" } } }, "localname": "LeaseBalanceSheetDisclosureTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesTables" ], "xbrltype": "textBlockItemType" }, "pfg_LeaseCostFinanceLeaseAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "n/a", "label": "Lease Cost Finance Lease [Abstract]", "terseLabel": "Finance lease cost:" } } }, "localname": "LeaseCostFinanceLeaseAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "pfg_LeaseLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Lease liabilities [Abstract]", "terseLabel": "Liabilities" } } }, "localname": "LeaseLiabilitiesAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "pfg_LeaseLiabilitiesEstablishedUponAdoptionOfAccountingGuidance": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of non-cash activity related to lease liabilities established upon adoption of accounting guidance.", "label": "Lease Liabilities Established upon Adoption of Accounting Guidance", "terseLabel": "Lease liabilities established upon adoption of accounting guidance" } } }, "localname": "LeaseLiabilitiesEstablishedUponAdoptionOfAccountingGuidance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilitiesPaymentsRollingMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Lease Liabilities, Payments, Rolling Maturity [Abstract]", "terseLabel": "Total leases, payments due for the twelve months ending December 31:" } } }, "localname": "LeaseLiabilitiesPaymentsRollingMaturityAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "pfg_LeaseLiabilityPaymentsDue": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments.", "label": "Lease, Liability, Payments, Due", "totalLabel": "Total lease payments" } } }, "localname": "LeaseLiabilityPaymentsDue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInNextRollingTwelveMonths": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due after fifth fiscal year following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Next Rolling Twelve Months", "totalLabel": "2020" } } }, "localname": "LeaseLiabilityPaymentsDueInNextRollingTwelveMonths", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInRollingAfterYearFive": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 6.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due after fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Rolling after Year Five", "totalLabel": "2025 and thereafter" } } }, "localname": "LeaseLiabilityPaymentsDueInRollingAfterYearFive", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInRollingYearFive": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 5.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due in fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Rolling Year Five", "totalLabel": "2024" } } }, "localname": "LeaseLiabilityPaymentsDueInRollingYearFive", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInRollingYearFour": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 4.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due in fourth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Rolling Year Four", "totalLabel": "2023" } } }, "localname": "LeaseLiabilityPaymentsDueInRollingYearFour", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInRollingYearThree": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 3.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due in third rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Rolling Year Three", "totalLabel": "2022" } } }, "localname": "LeaseLiabilityPaymentsDueInRollingYearThree", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityPaymentsDueInRollingYearTwo": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments, due in second rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lease, Liability, Payments, Due in Rolling Year Two", "totalLabel": "2021" } } }, "localname": "LeaseLiabilityPaymentsDueInRollingYearTwo", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LeaseLiabilityUndiscountedExcessAmount": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments.", "label": "Lease, Liability, Undiscounted Excess Amount", "totalLabel": "Less: interest" } } }, "localname": "LeaseLiabilityUndiscountedExcessAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilitiesOtherFairValueDisclosure": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 2.0, "parentTag": "us-gaap_LiabilitiesFairValueDisclosure", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents certain embedded derivatives to deliver underlying securities of structured investments to third parties and obligations of consolidated variable interest entities reported at fair value.", "label": "Liabilities Other Fair Value Disclosure", "negatedLabel": "Other liabilities" } } }, "localname": "LiabilitiesOtherFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilityForClaimsAdjustmentExpense": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Liability as of the balance sheet date for the costs estimated to be incurred in the settlement of unpaid claims.", "label": "Liability for Claims Adjustment Expense", "terseLabel": "Claim adjustment expense liabilities" } } }, "localname": "LiabilityForClaimsAdjustmentExpense", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilityForClaimsOtherThanShortDuration": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails": { "order": 1.0, "parentTag": "us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date for contracts other than short duration.", "label": "Liability For Claims Other Than Short Duration", "terseLabel": "Insurance contracts other than short duration" } } }, "localname": "LiabilityForClaimsOtherThanShortDuration", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilityForFuturePolicyBenefitsIndividualAnnuities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 1.0, "parentTag": "us-gaap_DepositContractsLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of the liability as of the balance sheet date pertaining to liabilities for individual annuities.", "label": "Liability for Future Policy Benefits Individual Annuities", "terseLabel": "Liabilities for individual annuities" } } }, "localname": "LiabilityForFuturePolicyBenefitsIndividualAnnuities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilityForFuturePolicyBenefitsUniversalLifeAndOtherReserves": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 2.0, "parentTag": "pfg_ContractholderFunds", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount as of the balance sheet date pertaining to reserves for universal life and other reserves.", "label": "Liability for Future Policy Benefits Universal Life and Other Reserves", "terseLabel": "Universal life and other reserves" } } }, "localname": "LiabilityForFuturePolicyBenefitsUniversalLifeAndOtherReserves", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseSupplementalAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense Supplemental [Abstract]", "terseLabel": "Amount not included in the rollforward above:" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseSupplementalAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "stringItemType" }, "pfg_LongTermCarePlansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A postretirement benefit plan that specifically covers long-term care costs.", "label": "Long Term Care Plans [Member]", "terseLabel": "Long-term care plans" } } }, "localname": "LongTermCarePlansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_LongTermDebtMinimumMaturityPeriod": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the minimum number of years for the maturity date debt when issued for it to be included in long-term debt.", "label": "Long-term Debt Minimum Maturity Period", "terseLabel": "Minimum maturity period at date of issuance for debt to be classified as long-term" } } }, "localname": "LongTermDebtMinimumMaturityPeriod", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "durationItemType" }, "pfg_LongTermDisabilityGroupLifeWaiverMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Product lines consisting of long-term disability and group life waiver insurance policies.", "label": "Long Term Disability Group Life Waiver [Member]", "terseLabel": "Long-Term Disability/Group Life Waiver" } } }, "localname": "LongTermDisabilityGroupLifeWaiverMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "domainItemType" }, "pfg_MarketValueAdjustmentsEmbeddedDerivatives": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 4.0, "parentTag": "pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Adjustment for the portion of the change in fair value of embedded derivatives related to customer behavior-related impacts, which is a risk we assume, to move that amount to benefits, claims and settlement expenses for segment profit (loss) reporting.", "label": "Market Value Adjustments, Embedded Derivatives", "terseLabel": "Market value adjustments of embedded derivatives" } } }, "localname": "MarketValueAdjustmentsEmbeddedDerivatives", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_MarketValueAdjustmentsFeeRevenues": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 3.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in fees and other revenues to net realized capital gains (losses) for segment profit (loss) reporting related to participating contract cash out gains/losses related to net realized capital losses/gains on the sale of invested assets used to fund the cash out of the contract at market value.", "label": "Market Value Adjustments, Fee Revenues", "negatedLabel": "Market value adjustments to fee revenues" } } }, "localname": "MarketValueAdjustmentsFeeRevenues", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_MaximumPeriodForExercisingOptionOnFailureOfPaymentToTrust": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Period failure to make payments to trust can be cured before automatic exercise of put options, in 'PnYnMnDTnHnMnS' format.", "label": "Maximum Period For Exercising Option On Failure Of Payment To Trust", "terseLabel": "Period failure to make payments to trust can be cured before automatic exercise of put options" } } }, "localname": "MaximumPeriodForExercisingOptionOnFailureOfPaymentToTrust", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "durationItemType" }, "pfg_MaximumValueOfSharesAvailableForPurchasePerYear": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The maximum value of company common stock employees may purchase each year under the Employee Stock Purchase Plan.", "label": "Maximum Value of Shares Available for Purchase Per Year", "terseLabel": "Maximum value of company common stock that can be purchased by an employee per year" } } }, "localname": "MaximumValueOfSharesAvailableForPurchasePerYear", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "monetaryItemType" }, "pfg_MeasurementInputLoanToValueRatioMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using a ratio equal to the mortgage amount divided by the appraised value of the property.", "label": "Measurement Input Loan To Value Ratio [Member]", "terseLabel": "Loan to value" } } }, "localname": "MeasurementInputLoanToValueRatioMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_MeasurementInputLongDurationInterestRateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using the rate curve the entity has determined market participants would use when pricing a financial instrument.", "label": "Measurement Input Long Duration Interest Rate [Member]", "terseLabel": "Long duration interest rate" } } }, "localname": "MeasurementInputLongDurationInterestRateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_MeasurementInputMarketInterestRateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using the prevailing market rate of interest for a loan based on the duration, type, quality and structure of the existing security.", "label": "Measurement Input Market Interest Rate [Member]", "terseLabel": "Market interest rate" } } }, "localname": "MeasurementInputMarketInterestRateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_MeasurementInputNonPerformanceRiskMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using risk of loss to counterparty for entity's failure to meet a contractual obligation to the counterparty.", "label": "Measurement Input Non Performance Risk [Member]", "terseLabel": "Non-performance risk" } } }, "localname": "MeasurementInputNonPerformanceRiskMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_MeasurementInputTerminalCapitalizationRateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using the rate used to estimate the resale value of a property at the end of the holding period.", "label": "Measurement Input Terminal Capitalization Rate [Member]", "terseLabel": "Terminal capitalization rate" } } }, "localname": "MeasurementInputTerminalCapitalizationRateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_MiddleAtlanticMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the Middle Atlantic region of the United States.", "label": "Middle Atlantic [Member]", "terseLabel": "Middle Atlantic" } } }, "localname": "MiddleAtlanticMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_MinorityInterestIncreaseFromContributionsFromNoncontrollingInterest": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents an increase in noncontrolling interest from issuance of additional equity interests or a business combination that occurred during the period.", "label": "Minority Interest Increase from Contributions from Noncontrolling Interest", "terseLabel": "Contributions from noncontrolling interest" } } }, "localname": "MinorityInterestIncreaseFromContributionsFromNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "pfg_MoneyMarketFundsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Money Market Funds Abstract", "terseLabel": "Money Market Funds" } } }, "localname": "MoneyMarketFundsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "pfg_MortgageLoansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.", "label": "Mortgage Loans [Member]", "terseLabel": "Mortgage loans" } } }, "localname": "MortgageLoansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "pfg_MountainMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the Mountain region of the United States.", "label": "Mountain [Member]", "terseLabel": "Mountain" } } }, "localname": "MountainMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_NatureOfOperationsAndSignificantAccountingPoliciesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Nature of Operations and Significant Accounting Policies" } } }, "localname": "NatureOfOperationsAndSignificantAccountingPoliciesDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_NetAmountAssetsSubjectToNetting": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial assets (reverse repurchase agreements and securities lending transactions) subject to master netting agreements or similar agreements, net of offsetting liabilities and collateral received.", "label": "Net Amount Assets Subject to Netting", "totalLabel": "Net amount of assets subject to netting agreements" } } }, "localname": "NetAmountAssetsSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetAmountLiabilitiesSubjectToNetting": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Value of derivative and other financial liabilities (repurchase agreements and securities borrowing transactions) subject to master netting agreements or similar agreements, net of offsetting assets and collateral pledged.", "label": "Net Amount Liabilities Subject to Netting", "totalLabel": "Net amount of liabilities subject to netting agreements" } } }, "localname": "NetAmountLiabilitiesSubjectToNetting", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetGainLossExcludingAvailableForSaleImpairments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the net realized and unrealized gains (losses), excluding impairment losses on available-for-sale securities, included in net income for the period as the result of selling or holding invested assets. This item includes the net gain or loss realized from the sale, exchange, redemption or retirement of securities and the unrealized holding gain or loss for certain invested assets. This item excludes other than temporary impairments on available-for-sale debt and equity securities.", "label": "Net Gain (Loss), Excluding Available-for-sale Impairments", "terseLabel": "Net realized capital gains (losses), excluding impairment losses on available-for-sale securities" } } }, "localname": "NetGainLossExcludingAvailableForSaleImpairments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "pfg_NetInvestmentIncomeLossMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The net investment income (loss).", "label": "Net Investment Income Loss [Member]", "terseLabel": "Net investment income" } } }, "localname": "NetInvestmentIncomeLossMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_NetRealizedCapitalGainsLossesIncomeTaxes": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails": { "order": 2.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Adjustment for the income tax effect of the pre-tax net realized capital gains (losses), as adjusted.", "label": "Net Realized Capital (Gains) Losses, Income Taxes", "verboseLabel": "Tax expense (benefit) related to net realized capital gains (losses), as adjusted" } } }, "localname": "NetRealizedCapitalGainsLossesIncomeTaxes", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetRealizedCapitalGainsLossesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The net realized gains or losses on investments.", "label": "Net Realized Capital Gains Losses [Member]", "terseLabel": "Net realized capital gains (losses)" } } }, "localname": "NetRealizedCapitalGainsLossesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cumulative net unrealized gains/losses on fixed maturities available-for-sale, equity securities available-for-sale and derivative instruments net of adjustments related to deferred acquisition costs, sales inducements, unearned revenue reserves, changes in policyholder benefits and claims and applicable income taxes.", "label": "Net Unrealized Gains, Losses, Available-for-sale Securities and Derivative Instruments", "totalLabel": "Net unrealized gains (losses) on available-for-sale securities and derivative instruments" } } }, "localname": "NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments" } } }, "localname": "NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "stringItemType" }, "pfg_NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 1.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the cumulative net unrealized gains and losses on fixed maturities available-for-sale, excluding hedged portions of those in fair value hedging.", "label": "Net Unrealized Gains, Losses, Debt Securities, Available-for-sale Securities", "terseLabel": "Net unrealized gains (losses) on fixed maturities, available-for-sale" } } }, "localname": "NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetUnrealizedGainsLossesDerivativeInstruments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 5.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the cumulative net unrealized gains/losses on derivatives in qualifying cash flow hedges.", "label": "Net Unrealized Gains, Losses, Derivative Instruments", "terseLabel": "Net unrealized gains (losses) on derivative instruments" } } }, "localname": "NetUnrealizedGainsLossesDerivativeInstruments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetUnrealizedGainsLossesOnImpairedFixedMaturitiesAvailableForSale": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The net amount of gross unrealized gains (losses) for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. This amount specifically relates to net unrealized gains (losses) since the time of impairment for securities for which the noncredit portion of the impairment loss was recognized in other comprehensive income.", "label": "Net Unrealized Gains (Losses) on Impaired Fixed Maturities Available-for-sale", "verboseLabel": "Net unrealized gains (losses) on impaired fixed maturities, available-for-sale related to changes in fair value subsequent to the impairment date" } } }, "localname": "NetUnrealizedGainsLossesOnImpairedFixedMaturitiesAvailableForSale", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NetUnrealizedGainsLossesOtherInvestmentsAndNoncontrollingInterestAdjustments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 6.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the cumulative net unrealized gains/losses on other investments and net unrealized gains/losses attributable to noncontrolling interests.", "label": "Net Unrealized Gains, Losses, Other Investments and Noncontrolling Interest Adjustments", "terseLabel": "Net unrealized gains (losses) on other investments and noncontrolling interest adjustments" } } }, "localname": "NetUnrealizedGainsLossesOtherInvestmentsAndNoncontrollingInterestAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_NewEnglandMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the New England region of the United States.", "label": "New England [Member]", "terseLabel": "New England" } } }, "localname": "NewEnglandMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_NonRecourseMortgagesAndNotesPayableConsolidateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents non-recourse mortgages and notes payable that qualify as long-term debt.", "label": "Non Recourse Mortgages And Notes Payable Consolidate [Member]", "terseLabel": "Non-recourse mortgages and notes payable" } } }, "localname": "NonRecourseMortgagesAndNotesPayableConsolidateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails" ], "xbrltype": "domainItemType" }, "pfg_NonperformingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Loans 90 days and greater delinquent.", "label": "Nonperforming [Member]", "terseLabel": "Non-performing" } } }, "localname": "NonperformingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable1.85PercentDue2017And3.125PercentDue2023And4.35PercentDue2043Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 1.85 percent that mature in 2017, notes payable with interest rate of 3.125 percent that mature in 2023, and notes payable with interest rate of 4.35 percent and mature in 2043.", "label": "Notes Payable1.85 Percent Due2017 And3.125 Percent Due2023 And4.35 Percent Due2043 [Member]", "terseLabel": "1.85% notes payable, due 2017; 3.125% notes payable, due 2023; and 4.35% notes payable, due 2043" } } }, "localname": "NotesPayable1.85PercentDue2017And3.125PercentDue2023And4.35PercentDue2043Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable1.85PercentDue2017Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 1.85 percent and will mature in 2017.", "label": "Notes Payable1.85 Percent Due2017 [Member]", "terseLabel": "1.85% notes payable, due 2017" } } }, "localname": "NotesPayable1.85PercentDue2017Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.125PercentDue2023Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.125 percent and will mature in 2023.", "label": "Notes Payable3.125 Percent Due2023 [Member]", "terseLabel": "3.125% notes payable, due 2023" } } }, "localname": "NotesPayable3.125PercentDue2023Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.1PercentDue2026AndNotesPayable4.3PercentDue2046Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.1 percent and will mature in 2026 and notes payable that bear an interest rate of 4.3 percent and will mature in 2046.", "label": "Notes Payable3.1 Percent Due2026 And Notes Payable4.3 Percent Due2046 [Member]", "terseLabel": "3.1% notes payable, due 2026 and 4.3% notes payable, due 2046" } } }, "localname": "NotesPayable3.1PercentDue2026AndNotesPayable4.3PercentDue2046Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.1PercentDue2026Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.1 percent and will mature in 2026.", "label": "Notes Payable3.1 Percent Due2026 [Member]", "terseLabel": "3.1% notes payable, due 2026" } } }, "localname": "NotesPayable3.1PercentDue2026Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.3PercentDue2022And4.625PercentDue2042Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.3 percent and will mature in 2022 and notes payable that bear an interest rate of 4.625 percent and will mature in 2042.", "label": "Notes Payable3.3 Percent Due2022 And4.625 Percent Due2042 [Member]", "terseLabel": "3.3% notes payable, due 2022 and 4.625% notes payable, due 2042" } } }, "localname": "NotesPayable3.3PercentDue2022And4.625PercentDue2042Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.3PercentDue2022Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.3 percent and will mature in 2022.", "label": "Notes Payable3.3 Percent Due2022 [Member]", "terseLabel": "3.3% notes payable, due 2022" } } }, "localname": "NotesPayable3.3PercentDue2022Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.4PercentDue2025Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.4 percent and will mature in 2025.", "label": "Notes Payable3.4 Percent Due2025 [Member]", "terseLabel": "3.4% notes payable, due 2025" } } }, "localname": "NotesPayable3.4PercentDue2025Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable3.7PercentDue2029Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 3.7 percent and will mature in 2029.", "label": "Notes Payable3.7 Percent Due2029 [Member]", "terseLabel": "3.7% notes payable, due 2029" } } }, "localname": "NotesPayable3.7PercentDue2029Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable4.35PercentDue2043Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 4.35 percent and will mature in 2043.", "label": "Notes Payable4.35 Percent Due2043 [Member]", "terseLabel": "4.35% notes payable, due 2043" } } }, "localname": "NotesPayable4.35PercentDue2043Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable4.3PercentDue2046Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 4.3 percent and will mature in 2046.", "label": "Notes Payable4.3 Percent Due2046 [Member]", "terseLabel": "4.3% notes payable, due 2046" } } }, "localname": "NotesPayable4.3PercentDue2046Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable4.625PercentDue2042Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 4.625 percent and will mature in 2042.", "label": "Notes Payable4.625 Percent Due2042 [Member]", "terseLabel": "4.625% notes payable, due 2042" } } }, "localname": "NotesPayable4.625PercentDue2042Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable4.7PercentDue2055Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 4.7 percent and will mature in 2055.", "label": "Notes Payable4.7 Percent Due2055 [Member]", "terseLabel": "4.7% notes payable, due 2055" } } }, "localname": "NotesPayable4.7PercentDue2055Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable6.05PercentDue2036IssuedDecember2006Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 6.05 percent and will mature in 2036, issued in December 2006.", "label": "Notes Payable6.05 Percent Due2036 Issued December2006 [Member]", "terseLabel": "6.05% notes payable, due 2036, issued in December 2006" } } }, "localname": "NotesPayable6.05PercentDue2036IssuedDecember2006Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable6.05PercentDue2036IssuedOctober2006Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 6.05 percent and will mature in 2036, issued in October 2006.", "label": "Notes Payable6.05 Percent Due2036 Issued October2006 [Member]", "terseLabel": "6.05% notes payable, due 2036, issued in October 2006" } } }, "localname": "NotesPayable6.05PercentDue2036IssuedOctober2006Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable6.05PercentDue2036Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 6.05 percent and will mature in 2036.", "label": "Notes Payable6.05 Percent Due2036 [Member]", "terseLabel": "6.05% notes payable, due 2036" } } }, "localname": "NotesPayable6.05PercentDue2036Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable7.875PercentDue2014And8.875PercentDue2019Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 7.875 percent that mature in 2014 and notes payable with interest rate of 8.875 percent that mature in 2019.", "label": "Notes Payable7.875 Percent Due2014 And8.875 Percent Due2019 [Member]", "terseLabel": "7.875% notes payable, due 2014 and 8.875% notes payable, due 2019" } } }, "localname": "NotesPayable7.875PercentDue2014And8.875PercentDue2019Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable7.875PercentDue2014Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 7.875 percent and will mature in 2014.", "label": "Notes Payable7.875 Percent Due2014 [Member]", "terseLabel": "7.875% notes payable, due 2014" } } }, "localname": "NotesPayable7.875PercentDue2014Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable8.2PercentDue2009Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 8.2 percent and matured in 2009. The maturity of these notes in August 2009 was refinanced with the proceeds from the issuance of $750.0 million of senior notes issued on May 18, 2009.", "label": "Notes Payable8.2 Percent Due2009 [Member]", "terseLabel": "8.2% notes payable, due 2009" } } }, "localname": "NotesPayable8.2PercentDue2009Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NotesPayable8.875PercentDue2019Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents notes payable that bear an interest rate of 8.875 percent and will mature in 2019.", "label": "Notes Payable8.875 Percent Due2019 [Member]", "terseLabel": "8.875% notes payable, due 2019" } } }, "localname": "NotesPayable8.875PercentDue2019Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "pfg_NumberOfContingentFundingAgreements": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Number of contingent funding agreements entered into by the entity.", "label": "Number of Contingent Funding Agreements", "terseLabel": "Number of contingent funding agreements" } } }, "localname": "NumberOfContingentFundingAgreements", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "integerItemType" }, "pfg_NumberOfLoansMoreThan90DaysPastDue": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the number of loans, which are more than 90 days past due or in nonaccrual status.", "label": "Number of Loans More than 90 Days Past Due", "terseLabel": "Number of loans which are more than 90 days past due or in nonaccrual status" } } }, "localname": "NumberOfLoansMoreThan90DaysPastDue", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "integerItemType" }, "pfg_ObligationsOfConsolidatedVariableInterestEntitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Amounts that one party is obligated to pay to another in accordance with an expressed or implied agreement of consolidated variable interest entities for which the fair value option was elected.", "label": "Obligations Of Consolidated Variable Interest Entities [Member]", "terseLabel": "Obligations of Consolidated VIEs" } } }, "localname": "ObligationsOfConsolidatedVariableInterestEntitiesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_BenefitsLossesAndExpenses", "weight": 1.0 }, "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 6.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Expenses other than those for payments of benefits, claims and policyholder dividends that are incurred related to the operations of the company. Includes commission expense, capitalization of deferred acquisitions costs (\"DAC\"), amortization of DAC, depreciation and amortization expense, interest expense on corporate debt, compensation costs and other general and administrative expenses.", "label": "Operating Expenses Including Deferred Acquisition Costs Capitalization and Amortization", "negatedLabel": "Operating expenses", "terseLabel": "Operating expenses", "verboseLabel": "Other operating costs and expenses" } } }, "localname": "OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "pfg_OperatingExpensesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Generally recurring costs associated with normal operations except for payment of benefits, claims and policyholder dividends.", "label": "Operating Expenses [Member]", "terseLabel": "Operating expense" } } }, "localname": "OperatingExpensesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "pfg_OperatingRevenueAndProfitLossFromSegmentsToConsolidatedLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Operating Revenue And Profit (Loss) From Segments To Consolidated [Line Items]", "verboseLabel": "Operating Revenue And Profit (Loss) From Segments To Consolidated" } } }, "localname": "OperatingRevenueAndProfitLossFromSegmentsToConsolidatedLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "pfg_OperatingRevenues": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 1.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Operating revenues is a measure of revenue for the operating segments. It is derived by adjusting total revenues for net realized capital gains and losses (except periodic settlements and accruals on derivatives not designated as hedging instruments), including their impact on recognition of front-end fee revenues, certain market value adjustments to fee revenues and amortization of hedge accounting book value adjustments for certain discontinued hedges, and revenue from the exited group medical insurance business. Operating revenues also includes operating revenues from real estate properties that qualify for discontinued operations.", "label": "Operating Revenues", "terseLabel": "Operating revenues", "totalLabel": "Total operating revenues" } } }, "localname": "OperatingRevenues", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherAssetsAsDefined": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 8.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The aggregate carrying amounts, as of the balance sheet date, of assets not separately disclosed in the condensed financial information of the registrant.", "label": "Other Assets, as Defined", "terseLabel": "Other assets" } } }, "localname": "OtherAssetsAsDefined", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherComprehensiveIncomeAvailableForSaleSecuritiesPeriodIncreaseDecreaseNetOfTax": { "auth_ref": [], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Net unrealized gains/losses on fixed maturities and equity securities available-for-sale net of adjustments related to deferred acquisition costs, sales inducements, unearned revenue reserves, changes in policyholder benefits and claims and applicable income taxes.", "label": "Other Comprehensive Income Available for Sale Securities Period Increase Decrease Net of Tax", "terseLabel": "Net unrealized gains (losses) on available-for-sale securities" } } }, "localname": "OtherComprehensiveIncomeAvailableForSaleSecuritiesPeriodIncreaseDecreaseNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "pfg_OtherComprehensiveIncomeDerivativesPeriodIncreaseDecreaseNetOfTax": { "auth_ref": [], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 3.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Net unrealized gains/losses on derivative instruments designated and qualifying as the effective portion of cash flow hedges net of adjustments related to deferred acquisition costs, sales inducements, and applicable income taxes.", "label": "Other Comprehensive Income Derivatives Period Increase (Decrease), Net of Tax", "terseLabel": "Net unrealized gains (losses) on derivative instruments" } } }, "localname": "OtherComprehensiveIncomeDerivativesPeriodIncreaseDecreaseNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "pfg_OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of Other Comprehensive Income (Loss) attributable to redeemable noncontrolling interest.", "label": "Other Comprehensive Income (Loss) Attributable to Redeemable Noncontrolling Interest", "verboseLabel": "Other comprehensive income (loss) attributable to redeemable noncontrolling interest" } } }, "localname": "OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherComprehensiveIncomeLossNetOfTaxExcludingRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Net of tax amount of other comprehensive income (loss) attributable to both parent entity and nonredeemable noncontrolling interest but excluding the portion attributable to redeemable noncontrolling interest.", "label": "Other Comprehensive Income (Loss), Net of Tax, Excluding Redeemable Noncontrolling Interest", "terseLabel": "Other comprehensive income (loss)" } } }, "localname": "OtherComprehensiveIncomeLossNetOfTaxExcludingRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "pfg_OtherComprehensiveIncomeReclassificationAdjustmentNetOfTax": { "auth_ref": [], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Noncredit portion of impairment losses on debt securities for the period that meet the criteria to have impairment losses bifurcated between net income (credit losses) and OCI (noncredit losses), net of related taxes and assumed changes in amortization patterns.", "label": "Other Comprehensive Income, Reclassification Adjustment, Net of Tax", "negatedLabel": "Noncredit component of impairment losses on fixed maturities, available-for-sale" } } }, "localname": "OtherComprehensiveIncomeReclassificationAdjustmentNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "pfg_OtherCorporateEquitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Investments in corporate equity securities classified as other.", "label": "Other Corporate Equities [Member]", "terseLabel": "Other corporate" } } }, "localname": "OtherCorporateEquitiesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "pfg_OtherInvestmentTypesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This element represents types of investments not otherwise specifically identified.", "label": "Other Investment Types [Member]", "terseLabel": "Other investment types" } } }, "localname": "OtherInvestmentTypesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "domainItemType" }, "pfg_OtherInvestmentsFairValueDisclosure": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents invested assets not specifically identified in the statement of financial position, excluding derivative assets. This includes invested assets such as seed money and commercial mortgage loans of consolidated variable interest entities reported at fair value.", "label": "Other Investments, Fair Value Disclosure", "terseLabel": "Other investments" } } }, "localname": "OtherInvestmentsFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherInvestmentsFairValueOption": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The balance represents the amount of commercial mortgage loans of consolidated variable interest entities reported as part of other investments for which the fair value option has been elected and an equity method investment for which the fair value option has been elected.", "label": "Other Investments Fair Value Option", "terseLabel": "Other investments measured at fair value under fair value option" } } }, "localname": "OtherInvestmentsFairValueOption", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "pfg_OtherInvestmentsOther": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 8.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Other investments include, but are not limited to, derivative assets, commercial mortgage loans of consolidated variable interest entities and company's ownership in corporate sponsored mutual funds.", "label": "Other Investments, Other", "terseLabel": "Other investments" } } }, "localname": "OtherInvestmentsOther", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherLeaseCost": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 4.0, "parentTag": "us-gaap_LeaseCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of other lease cost recognized by lessee for lease contract.", "label": "Other Lease, Cost", "terseLabel": "Other lease cost" } } }, "localname": "OtherLeaseCost", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherLiabilitiesAsDefined": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 4.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The aggregate carrying amounts, as of the balance sheet date, of liabilities not separately disclosed in the condensed financial information of the registrant.", "label": "Other Liabilities, as Defined", "terseLabel": "Other liabilities" } } }, "localname": "OtherLiabilitiesAsDefined", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherLiabilitiesAsDefinedMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Certain embedded derivatives to deliver underlying securities of structured investments to third parties and obligations of consolidated variable interest entities reported at fair value.", "label": "Other Liabilities As Defined [Member]", "terseLabel": "Other liabilities" } } }, "localname": "OtherLiabilitiesAsDefinedMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_OtherLimitedPartnershipAndFundInterestsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This category includes information about investments in 1) certain partnerships where the investor's return is in the form of income tax credits and 2) other partnerships and funds where the returns are from net investment income.", "label": "Other Limited Partnership And Fund Interests [Member]", "terseLabel": "Other investments: Other limited partnership and fund interests" } } }, "localname": "OtherLimitedPartnershipAndFundInterestsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_OtherNonqualifiedStockOptionDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Other Nonqualified Stock Option Disclosures [Abstract]", "terseLabel": "Other nonqualified stock option disclosures" } } }, "localname": "OtherNonqualifiedStockOptionDisclosuresAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "stringItemType" }, "pfg_OtherPlanAssetsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Other plan assets not separately identified, including cash and net (payables)/receivables for single client separate accounts.", "label": "Other Plan Assets [Member]", "terseLabel": "Other" } } }, "localname": "OtherPlanAssetsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlowsAndAccretion": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held due to increases in cash flows expected to be collected and recognized over the remaining life of the security, net of accretion of the bifurcated credit loss amount.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Cash Flows and Accretion", "terseLabel": "Net reduction (increase) for positive changes in cash flows expected to be collected and amortization" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlowsAndAccretion", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsForeignCurrencyTranslationAdjustments": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held due to foreign currency translation adjustments.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Foreign Currency Translation Adjustments", "terseLabel": "Foreign currency translation adjustment" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsForeignCurrencyTranslationAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsSecuritiesSoldChangeInStatus": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of the impaired security during the period or due to a change in status of the impaired security because of a change in the entity's intent to either sell the impaired security or it has become more likely than not that the entity will be required to sell the security before recovery of its cost basis.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold, Change in Status", "terseLabel": "Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsSecuritiesSoldChangeInStatus", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableForSaleSecurities": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of other than temporary impairment loss on an available-for-sale debt security related to factors other than credit losses when the entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis. This amount, which includes the portion attributable to the noncontrolling interest, if any, is a portion of the deduction from the total impairment losses of investments (before taxes) presented on the income statement; this amount is also referred to as the amount incurred by the reporting entity or the consolidated entity.", "label": "Other than Temporary Impairment Losses, Investments Portion in Other Comprehensive Income, before Tax, Including Portion Attributable to Noncontrolling Interest, Available-for-sale Securities", "terseLabel": "Other-than-temporary impairments in AOCI" } } }, "localname": "OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableForSaleSecurities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_OtherThanTemporaryImpairmentLossesNetOfRecoveriesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Total other-than-temporary impairment losses on available-for-sale securities reported in the consolidated statement of operations.", "label": "Other-than-temporary impairment losses, net of recoveries" } } }, "localname": "OtherThanTemporaryImpairmentLossesNetOfRecoveriesAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails" ], "xbrltype": "stringItemType" }, "pfg_OtherThanTemporaryImpairmentLossesRecoveriesInvestmentsAvailableForSaleSecurities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount by which the fair value of an investment in securities categorized as available-for-sale is less than or more than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.", "label": "Other Than Temporary Impairment Losses Recoveries Investments Available For Sale Securities", "negatedLabel": "Net other-than-temporary impairment (losses) recoveries", "negatedTerseLabel": "Net other-than-temporary impairment (losses) recoveries on available-for-sale securities" } } }, "localname": "OtherThanTemporaryImpairmentLossesRecoveriesInvestmentsAvailableForSaleSecurities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "pfg_OtherTypesOfInvestmentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Other Types of Investments [Abstract]", "terseLabel": "Other Types of Investments" } } }, "localname": "OtherTypesOfInvestmentsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "stringItemType" }, "pfg_PacificMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the Pacific region of the United States.", "label": "Pacific [Member]", "terseLabel": "Pacific" } } }, "localname": "PacificMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_ParentAndSubsidiariesNotesGuarantorAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The axis of all parent companies and/or subsidiaries when a parent guarantees notes issued by a subsidiary.", "label": "Parent and Subsidiaries - Notes Guarantor [Axis]" } } }, "localname": "ParentAndSubsidiariesNotesGuarantorAxis", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "pfg_ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The axis of all parent companies and/or subsidiaries when a subsidiary guarantees obligations of its parent.", "label": "Parent and Subsidiaries - Shelf Registration Debt Guarantor [Axis]" } } }, "localname": "ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "stringItemType" }, "pfg_ParticipatingPoliciesAsPercentageOfNumberOfLifeInsurancePoliciesInForce": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This percent places participating policies in the numerator and total number of life insurance policies in force in the denominator. Participating insurance contracts allow policyholders to share in the experience of the entity, primarily through policy dividends.", "label": "Participating Policies as Percentage of Number of Life Insurance Policies in Force", "terseLabel": "Participating business as a percentage of life insurance policies in force (as a percent)" } } }, "localname": "ParticipatingPoliciesAsPercentageOfNumberOfLifeInsurancePoliciesInForce", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "percentItemType" }, "pfg_PaymentsToAcquirePropertyPlantAndEquipmentNet": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 8.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The net cash inflow/outflow associated with the acquisition, sales and disposals of property, plant and equipment, and other productive assets, including intangible assets for software.", "label": "Payments to Acquire Property, Plant, and Equipment, Net", "negatedLabel": "Net (purchases) sales of property and equipment" } } }, "localname": "PaymentsToAcquirePropertyPlantAndEquipmentNet", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossBeforeTaxFromCurrentYearAmendments": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit), related to plan amendments from the current fiscal year.", "label": "Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax, From Current Year Amendments", "terseLabel": "Prior service cost (benefit) related to current year amendments" } } }, "localname": "PensionAndOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossBeforeTaxFromCurrentYearAmendments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PensionPlansDefinedBenefitCashBalanceBenefitMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Plan designed to provide participants with a defined benefit at retirement based on an accrual of a cash balance. Excludes other postretirement benefit plans.", "label": "Pension Plans Defined Benefit Cash Balance Benefit [Member]", "terseLabel": "Pension benefits, Cash balance benefit" } } }, "localname": "PensionPlansDefinedBenefitCashBalanceBenefitMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_PensionPlansDefinedBenefitTraditionalBenefitMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Plan designed to provide participants with a defined benefit at retirement based on an accrual of final average pay benefit. Excludes other postretirement benefit plans.", "label": "Pension Plans Defined Benefit Traditional Benefit [Member]", "terseLabel": "Pension benefits, Traditional benefit" } } }, "localname": "PensionPlansDefinedBenefitTraditionalBenefitMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_PercentageOfAnnualPremiumOnOptionsUnexercisedPortion": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage of annual premium applied to the unexercised portion of options.", "label": "Percentage of Annual Premium On Options Unexercised Portion", "terseLabel": "Annual put premium (as a percent)" } } }, "localname": "PercentageOfAnnualPremiumOnOptionsUnexercisedPortion", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "percentItemType" }, "pfg_PercentageOfMortgageLoans": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the specific geographic distribution or property type distribution amount as a percentage of the total amortized cost of mortgage loans.", "label": "Percentage of Mortgage Loans", "terseLabel": "Percent of mortgage loans (as a percent)" } } }, "localname": "PercentageOfMortgageLoans", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "percentItemType" }, "pfg_PercentageOfSemiAnnualPremiumOnOptionsUnexercisedPortion": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage of semi-annual premium applied to the unexercised portion of options.", "label": "Percentage of Semi-annual Premium On Options Unexercised Portion", "terseLabel": "Semi-annual put premium (as a percent)" } } }, "localname": "PercentageOfSemiAnnualPremiumOnOptionsUnexercisedPortion", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "percentItemType" }, "pfg_PerformanceFeeRecognizedDueToRealEstateInvestmentTeamRealignment": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of performance fee revenue recognized due to a real estate investment team realignment.", "label": "Performance Fee Recognized Due to Real Estate Investment Team Realignment", "terseLabel": "Performance fee recognized resulting from realignment of a real estate investment team" } } }, "localname": "PerformanceFeeRecognizedDueToRealEstateInvestmentTeamRealignment", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PerformingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Loans that are current and less than 90 days delinquent.", "label": "Performing [Member]", "terseLabel": "Performing" } } }, "localname": "PerformingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_PeriodicSettlementOnDerivatives": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 9.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of periodic settlements on derivatives recognized in statement of operations.", "label": "Periodic Settlement on Derivatives", "terseLabel": "Amounts related to periodic settlements on derivatives" } } }, "localname": "PeriodicSettlementOnDerivatives", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PlanAssetsHeldInRabbiTrusts": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Defined benefit plan assets held in Rabbi trusts.", "label": "Plan Assets Held in Rabbi Trusts", "terseLabel": "Assets held in Rabbi trusts" } } }, "localname": "PlanAssetsHeldInRabbiTrusts", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PlanAssetsIncludedInTrustOwnedLifeInsuranceContract": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Plan assets included in the U.S. equity and international equity portfolios that are included in a trust owned life insurance contract.", "label": "Plan Assets Included in Trust Owned Life Insurance Contract", "terseLabel": "Fair value of plan assets included in trust owned life insurance contract" } } }, "localname": "PlanAssetsIncludedInTrustOwnedLifeInsuranceContract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PlanLiabilitiesHeldInRabbiTrusts": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Defined benefit plan liabilities held in Rabbi trusts.", "label": "Plan Liabilities Held in Rabbi Trusts", "terseLabel": "Liabilities held in Rabbi trusts" } } }, "localname": "PlanLiabilitiesHeldInRabbiTrusts", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PooledSeparateAccountInvestmentsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Pension plan assets comprising investments in pooled separate accounts.", "label": "Pooled Separate Account Investments [Member]", "terseLabel": "Pooled separate account investments" } } }, "localname": "PooledSeparateAccountInvestmentsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_Post65MedicalPlansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A postretirement benefit plan that specifically covers medical costs for participants age 65 and over.", "label": "Post65 Medical Plans [Member]", "terseLabel": "Post-65 medical plans" } } }, "localname": "Post65MedicalPlansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "pfg_PreCapitalizedTrustSecuritiesSold": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Pre-capitalized trust securities in a Rule 144A private placement.", "label": "Pre-Capitalized Trust Securities Sold", "terseLabel": "Pre-capitalized trust securities sold" } } }, "localname": "PreCapitalizedTrustSecuritiesSold", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PreTaxOtherAdjustmentsInReconcilingSegmentRevenuesToConsolidatedIncome": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails": { "order": 2.0, "parentTag": "pfg_InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of other adjustments before tax in reconciling segment revenues from contracts with customers to consolidated revenues from fees and commissions.", "label": "Pre-Tax Other Adjustments in Reconciling Segment Revenues to Consolidated Income", "terseLabel": "Pre-tax other adjustments" } } }, "localname": "PreTaxOtherAdjustmentsInReconcilingSegmentRevenuesToConsolidatedIncome", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PretaxOperatingEarnings": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 1.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Pre-tax operating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting income before income taxes for pre-tax net realized capital gains (losses), as adjusted, pre-tax other adjustments management believes are not indicative of overall operating trends and certain adjustments related to equity method investments.", "label": "Pre-tax Operating Earnings", "terseLabel": "Pre-tax operating earnings (losses)" } } }, "localname": "PretaxOperatingEarnings", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PrincipalFinancialServicesIncAndPrincipalLifeInsuranceCompanyAndPrincipalFinancialGroupCoborrowersMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the information pertaining to Principal Financial Services, Inc., Principal Life Insurance Company, and Principal Financial Group as co-borrowers.", "label": "Principal Financial Services Inc And Principal Life Insurance Company And Principal Financial Group Coborrowers [Member]", "terseLabel": "PFG, PFS, Principal Life as co-borrowers" } } }, "localname": "PrincipalFinancialServicesIncAndPrincipalLifeInsuranceCompanyAndPrincipalFinancialGroupCoborrowersMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_PrincipalFinancialServicesIncAndPrincipalLifeInsuranceCompanyAndPrincipalFinancialServicesVLTDAndPrincipalFinancialGroupCoborrowersMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the information pertaining to Principal Financial Services, Inc., Principal Life Insurance Company, Principal Financial Services V (UK) LTD, and Principal Financial Group as co-borrowers.", "label": "Principal Financial Services Inc And Principal Life Insurance Company And Principal Financial Services V L T D And Principal Financial Group Coborrowers [Member]", "terseLabel": "PFG, PFS, Principal Life and Principal Financial Services V (UK) LTD as co-borrowers" } } }, "localname": "PrincipalFinancialServicesIncAndPrincipalLifeInsuranceCompanyAndPrincipalFinancialServicesVLTDAndPrincipalFinancialGroupCoborrowersMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_PrincipalInternationalChileMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the information pertaining to our Chilean operations within our Principal International operating segment.", "label": "Principal International Chile [Member]", "terseLabel": "Principal International Chile" } } }, "localname": "PrincipalInternationalChileMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_PrincipalLifeInsuranceCompanyConsolidatedMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The primary insurance company of Principal Financial Group, Inc. along with its consolidated subsidiaries.", "label": "Principal Life Insurance Company Consolidated [Member]", "terseLabel": "Principal Life Insurance Company" } } }, "localname": "PrincipalLifeInsuranceCompanyConsolidatedMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesContractholderFundingAgreementsDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "domainItemType" }, "pfg_ProceedsFromMaturitiesRepaymentsAndCallsOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 3.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow from maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and equity securities held for investment purposes and measured at fair value with change in fair value recognized in net income (FV-NI). Excludes proceeds from trading securities purchased and held principally for the purpose of selling them in the near term (thus held for only a short period of time).", "label": "Proceeds from Maturities, Repayments and Calls of Debt Securities, Available-for-Sale and Equity Securities, FV-NI", "terseLabel": "Fixed maturities available-for-sale and equity securities with intent to hold: Maturities" } } }, "localname": "ProceedsFromMaturitiesRepaymentsAndCallsOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_ProceedsFromPaymentsForTradingSecuritiesAndEquitySecuritiesWithOperatingIntent": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 6.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 8.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow (outflow) from sales and purchases of trading securities and equity securities with operating intent.", "label": "Proceeds from (Payments for) Trading Securities and Equity Securities with Operating Intent", "verboseLabel": "Net cash flows for trading securities and equity securities with operating intent" } } }, "localname": "ProceedsFromPaymentsForTradingSecuritiesAndEquitySecuritiesWithOperatingIntent", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_ProceedsFromSaleOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 2.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow from sale of investment in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and equity securities held for investment purposes and measured at fair value with change in fair value recognized in net income (FV-NI). Excludes proceeds from trading securities purchased and held principally for the purpose of selling them in the near term (thus held for only a short period of time).", "label": "Proceeds from Sale of Debt Securities, Available-for-Sale, and Equity Securities, FV-NI", "terseLabel": "Fixed maturities available-for-sale and equity securities with intent to hold: Sales" } } }, "localname": "ProceedsFromSaleOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_ProductsAndServicesEliminationsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Eliminations between revenues disaggregated by products and services.", "label": "Products And Services Eliminations [Member]", "terseLabel": "Revenue by type - Eliminations" } } }, "localname": "ProductsAndServicesEliminationsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_ProvisionDeferredIncomeTaxBenefitsExpense": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails": { "order": 7.0, "parentTag": "pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the applicable deferred income tax impacts of cumulative net unrealized gains/losses on fixed maturities available-for-sale, equity securities available-for-sale and derivative instruments net of adjustments related deferred acquisition costs, sales inducements, unearned revenue reserves, and changes in policyholder benefits and claims.", "label": "Provision Deferred Income Tax Benefits, Expense", "terseLabel": "Provision for deferred income tax benefits (taxes)" } } }, "localname": "ProvisionDeferredIncomeTaxBenefitsExpense", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetUnrealizedGainsAndLossesOnAvailableForSaleSecuritiesAndDerivativeInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_PurchaseOfSubsidiarySharesFromRedeemableNoncontrollingInterest": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Represents a decrease in the redeemable noncontrolling interest by purchase of subsidiary shares from redeemable noncontrolling interest holders.", "label": "Purchase of Subsidiary Shares from Redeemable Noncontrolling Interest", "negatedLabel": "Purchase of subsidiary shares from redeemable noncontrolling interest" } } }, "localname": "PurchaseOfSubsidiarySharesFromRedeemableNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_QuantitativeInformationLevel3FairValueMeasurementsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of quantitative information about the inputs used in the fair value measurement of assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). This disclosure may include, but is not limited to, the fair value of the asset or liability, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of inputs, and the weighted averages of the inputs.", "label": "Quantitative Information Level 3 Fair Value Measurements [Table Text Block]", "terseLabel": "Quantitative Information about Level 3 Fair Value Measurements (Table)" } } }, "localname": "QuantitativeInformationLevel3FairValueMeasurementsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "pfg_RealEstateDepreciationExpense": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of depreciation expense on real estate for the period.", "label": "Real Estate Depreciation Expense", "terseLabel": "Depreciation expense on invested real estate" } } }, "localname": "RealEstateDepreciationExpense", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "monetaryItemType" }, "pfg_RealEstateInvestmentAccumulatedDepreciation": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount as of the balance sheet date of accumulated depreciation pertaining to invested real estate.", "label": "Real Estate Investment, Accumulated Depreciation", "terseLabel": "Accumulated depreciation on invested real estate" } } }, "localname": "RealEstateInvestmentAccumulatedDepreciation", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "monetaryItemType" }, "pfg_RealEstateJointVenturesExitedMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Certain real estate joint ventures exited by the entity via an exchange agreement, which resulted in the entity transferring interest in certain real estate properties in exchange for the joint venture partner's interest in certain other real estate properties, and subsequent sales of certain real estate properties.", "label": "Real Estate Joint Ventures Exited [Member]", "terseLabel": "Certain real estate joint ventures" } } }, "localname": "RealEstateJointVenturesExitedMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "domainItemType" }, "pfg_RealEstatePropertiesReceived": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of real estate properties received.", "label": "Real Estate Properties Received", "terseLabel": "Real estate properties received" } } }, "localname": "RealEstatePropertiesReceived", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_RealizedInvestmentGainsLossesNetOfTax": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The net realized gains or losses on investments during the period, net of tax, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.", "label": "Realized Investment Gains (Losses), Net of Tax", "terseLabel": "Net after-tax realized capital gain" } } }, "localname": "RealizedInvestmentGainsLossesNetOfTax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ReconciliationOfDepreciationAndAmortizationExpenseFromSegmentsToConsolidatedTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of all significant reconciling items in the reconciliation of total depreciation and amortization expense from reportable segments to the entity's corresponding consolidated expense.", "label": "Reconciliation of Depreciation and Amortization Expense from Segments to Consolidated [Table Text Block]", "terseLabel": "Reconciliation of Depreciation and Amortization Expense from Segments to Consolidated (Table)" } } }, "localname": "ReconciliationOfDepreciationAndAmortizationExpenseFromSegmentsToConsolidatedTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationTables" ], "xbrltype": "textBlockItemType" }, "pfg_ReconciliationOfNetRealizedCapitalGainsLossesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Reconciliation of Net Realized Capital Gains (Losses) [Abstract]", "terseLabel": "Segment Information: Net realized capital gains (losses), as adjusted" } } }, "localname": "ReconciliationOfNetRealizedCapitalGainsLossesAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "stringItemType" }, "pfg_ReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Identification, description, and amounts of all significant reconciling items in the reconciliation of (1) operating revenues from reportable segments to consolidated revenues and (2) pre-tax operating earnings from reportable segments to consolidated income before income taxes.", "label": "Reconciliation Of Operating Revenue And Profit (Loss) From Segments To Consolidated [Table]" } } }, "localname": "ReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "pfg_ReconciliationOfUnpaidClaimsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Reconciliation Of Unpaid Claims Abstract", "terseLabel": "Reconciling items" } } }, "localname": "ReconciliationOfUnpaidClaimsAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "stringItemType" }, "pfg_RedeemableNoncontrollingInterestChangeInShareBasedCompensation": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Represents an increase (decrease) in redeemable noncontrolling interest during the period as a result of change in the share-based compensation attributable to the redeemable noncontrolling interest.", "label": "Redeemable Noncontrolling Interest, Change in Share-based Compensation", "terseLabel": "Stock-based compensation attributable to redeemable noncontrolling interest" } } }, "localname": "RedeemableNoncontrollingInterestChangeInShareBasedCompensation", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_RedeemableNoncontrollingInterestDecreaseFromDeconsolidation": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of the reduction or elimination during the period of a redeemable noncontrolling interest resulting from the parent's loss of control and deconsolidation of the entity in which one or more outside parties had a redeemable noncontrolling interest.", "label": "Redeemable Noncontrolling Interest Decrease From Deconsolidation", "negatedLabel": "Redeemable noncontrolling interest of deconsolidated entities" } } }, "localname": "RedeemableNoncontrollingInterestDecreaseFromDeconsolidation", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustmentsShortDurationInsuranceContracts": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer, related to short-duration insurance contracts.", "label": "Reinsurance Recoverable for Unpaid Claims and Claims Adjustments, Short-duration Insurance Contracts", "terseLabel": "Reinsurance recoverable on unpaid claims" } } }, "localname": "ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustmentsShortDurationInsuranceContracts", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ReinsuranceRecoverablesClaimsReceived": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of net ceded reinsurance recoverables related to claims that have been received.", "label": "Reinsurance Recoverables, Claims Received", "verboseLabel": "Net ceded reinsurance recoverables related to claims received" } } }, "localname": "ReinsuranceRecoverablesClaimsReceived", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ReinsuranceRecoverablesClaimsReceivedLargestCededReinsurersAmount": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of net ceded reinsurance recoverables related to claims that have been received, pertaining to the largest ceded reinsurers, disclosed as a concentration of credit risk.", "label": "Reinsurance Recoverables, Claims Received, Largest Ceded Reinsurers, Amount", "terseLabel": "Amount of net ceded reinsurance recoverables related to claims received with five largest ceded reinsurers" } } }, "localname": "ReinsuranceRecoverablesClaimsReceivedLargestCededReinsurersAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ReinsuranceRecoverablesClaimsReceivedLargestCededReinsurersPercent": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage of net ceded reinsurance recoverables related to claims that have been received, pertaining to the largest ceded reinsurers, disclosed as a concentration of credit risk.", "label": "Reinsurance Recoverables, Claims Received, Largest Ceded Reinsurers, Percent", "terseLabel": "Percentage of net ceded reinsurance recoverables related to claims received with five largest ceded reinsurers (as a percent)" } } }, "localname": "ReinsuranceRecoverablesClaimsReceivedLargestCededReinsurersPercent", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "percentItemType" }, "pfg_ReinsuranceRecoverablesClaimsReceivedNumberOfLargestCededReinsurers": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The number of ceded reinsurers for which the amount of net ceded reinsurance recoverables related to claims received is disclosed as a concentration of credit risk.", "label": "Reinsurance Recoverables, Claims Received, Number of Largest Ceded Reinsurers", "terseLabel": "Number of largest ceded reinsurers" } } }, "localname": "ReinsuranceRecoverablesClaimsReceivedNumberOfLargestCededReinsurers", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "integerItemType" }, "pfg_RevenueMultiplesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using the rate used to estimate the revenue multiples.", "label": "Revenue Multiples [Member]", "terseLabel": "Revenue multiples" } } }, "localname": "RevenueMultiplesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_RevenuesAndRelatedBenefitsExpensePolicyTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for premium, fee and other revenue recognition, including the basis for measurement and the timing of recognition of revenue from insurance premiums and fees received from contractholders. Also describes an insurance entity's accounting policy for recognition of related benefit, claim and settlement expenses.", "label": "Revenues and Related Benefits Expense Policy [Text Block]", "terseLabel": "Recognition of Premiums and Other Considerations, Fees and Other Revenues and Benefits - Policy" } } }, "localname": "RevenuesAndRelatedBenefitsExpensePolicyTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "pfg_ReverseRepurchaseAgreementMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Securities or other assets purchased under reverse repurchase agreements.", "label": "Reverse Repurchase Agreement [Member]", "terseLabel": "Reverse repurchase agreements" } } }, "localname": "ReverseRepurchaseAgreementMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_ScheduleOfAccountsNotesLoansAndFinancingReceivablePurchasedAndSoldTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the various types of trade accounts and notes receivable purchased and sold.", "label": "Schedule Of Accounts Notes Loans And Financing Receivable Purchased And Sold [Table Text Block]", "terseLabel": "Mortgage Loans Purchased and Sold (Table)" } } }, "localname": "ScheduleOfAccountsNotesLoansAndFinancingReceivablePurchasedAndSoldTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of amortized cost and fair value of fixed maturities available-for-sale by contractual maturity.", "label": "Schedule of Available-for-sale Securities, Debt Maturities [Table Text Block]", "terseLabel": "Fixed Maturities Available-for-Sale by Contractual Maturity (Table)" } } }, "localname": "ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation, including assumed discount rate and rate of compensation increase.", "label": "Schedule of Benefit Obligation [Table Text Block]", "terseLabel": "Weighted-Average Assumptions Used to Determine Benefit Obligations (Table)" } } }, "localname": "ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfChangeInMaximumFutureEarningsOfClosedBlockTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure reflecting the change in the maximum future earnings of the closed block.", "label": "Schedule of Change in Maximum Future Earnings of Closed Block [Table Text Block]", "terseLabel": "Change in Maximum Future Earnings of the Closed Block (Table)" } } }, "localname": "ScheduleOfChangeInMaximumFutureEarningsOfClosedBlockTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureClosedBlockTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCommercialMortgageLoansByGeographicRegionAndSpecificCollateralPropertyTypeTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure itemizing the commercial mortgage loan portfolio by both geographic distribution and property type distribution.", "label": "Schedule of Commercial Mortgage Loans by Geographic Region and Specific Collateral Property Type [Table Text Block ]", "terseLabel": "Commercial Mortgage Loans by Geographic Distribution and Property Type Distribution (Table)" } } }, "localname": "ScheduleOfCommercialMortgageLoansByGeographicRegionAndSpecificCollateralPropertyTypeTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCommercialMortgageLoansCreditQualityIndicatorsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure related to commercial mortgage loans by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but are not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics.", "label": "Schedule of Commercial Mortgage Loans Credit Quality Indicators [Table Text Block]", "terseLabel": "Commercial Mortgage Loan Portfolio by Credit Risk (Table)" } } }, "localname": "ScheduleOfCommercialMortgageLoansCreditQualityIndicatorsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of compensation-related costs for share-based compensation, including amounts charged to income and amount capitalized as part of an asset.", "label": "Schedule of Compensation Related Costs Charged to Income or Capitalized as Asset [Table Text Block]", "terseLabel": "Stock-Based Compensation Disclosures (Table)" } } }, "localname": "ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCondensedFinancialStatementsNotesGuarantorTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of condensed financial statements. This table is for a parent's guarantee of medium term notes issued by a subsidiary.", "label": "Schedule of Condensed Financial Statements Notes Guarantor [Table Text Block]", "terseLabel": "Condensed Consolidating Financial Information, Notes Guarantor (Table)" } } }, "localname": "ScheduleOfCondensedFinancialStatementsNotesGuarantorTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCondensedFinancialStatementsShelfRegistrationDebtGuarantorTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of condensed financial statements. This table is for a subsidiary's guarantee of securities issued under a shelf registration of its parent.", "label": "Schedule of Condensed Financial Statements Shelf Registration Debt Guarantor [Table Text Block]", "terseLabel": "Condensed Consolidating Financial Information, Shelf Registration Guarantor (Table)" } } }, "localname": "ScheduleOfCondensedFinancialStatementsShelfRegistrationDebtGuarantorTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of variable interest entities carrying amount of consolidated assets that are collateral for the VIE's obligations and consolidated liabilities.", "label": "Schedule of Consolidated Variable Interest Entity, Assets (Liabilities) [Table Text Block]", "terseLabel": "Carrying Amounts of Assets and Liabilities of Consolidated Variable Interest Entities (Table)" } } }, "localname": "ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfContractholderFundsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the carrying amounts as of the balance sheet date of the components of contractholder funds, including details of investment contracts, individual annuities, and reserves for universal life insurance.", "label": "Schedule of Contractholder Funds [Table Text Block]", "terseLabel": "Contractholder Funds (Table)" } } }, "localname": "ScheduleOfContractholderFundsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of cumulative basis adjustments for fair value hedges.", "label": "Schedule of Cumulative Basis Adjustments for Fair Value Hedges [Table Text Block]", "terseLabel": "Fair Value Hedges (Table)" } } }, "localname": "ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfDeferredAcquisitionCostsDisclosureTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the reconciliation of deferred acquisition costs from the beginning of a period to the end of a period.", "label": "Schedule of Deferred Acquisition Costs Disclosure [Table Text Block]", "terseLabel": "Deferred Acquisition Costs Rollforward (Table)" } } }, "localname": "ScheduleOfDeferredAcquisitionCostsDisclosureTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfDefinedBenefitPensionPlansSupplementalInformationTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of supplemental information for defined benefit pension plans, separately showing information for qualified and non-qualified plans.", "label": "Schedule of Defined Benefit Pension Plans Supplemental Information [Table Text Block]", "terseLabel": "Defined Benefit Pension Plans Supplemental Information (Table)" } } }, "localname": "ScheduleOfDefinedBenefitPensionPlansSupplementalInformationTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfEffectOfDerivativesInFairValueAndCashFlowHedgingRelationshipsAndRelatedHedgedItemsOnConsolidatedStatementOfOperationsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of effect of derivatives in fair value and cash flow hedging relationships and the related hedged items on the consolidated statements of operations.", "label": "Schedule of Effect of Derivatives in Fair Value and Cash Flow Hedging Relationships and Related Hedged Items on Consolidated Statement of Operations [Table Text Block]", "terseLabel": "Effect of Fair Value and Cash Flow Hedges on Consolidated Statements of Operations (Table)" } } }, "localname": "ScheduleOfEffectOfDerivativesInFairValueAndCashFlowHedgingRelationshipsAndRelatedHedgedItemsOnConsolidatedStatementOfOperationsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfEffectOfReinsuranceOnPremiumsAndOtherConsiderationAndPolicyAndContractBenefitsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of effect of reinsurance on premiums and other consideration and policy and contract benefits.", "label": "Schedule of Effect of Reinsurance on Premiums and Other Consideration and Policy and Contract Benefits [Table Text Block]", "terseLabel": "Effects of Reinsurance on Premiums and Other Considerations and Policy and Contract Benefits (Table)" } } }, "localname": "ScheduleOfEffectOfReinsuranceOnPremiumsAndOtherConsiderationAndPolicyAndContractBenefitsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfExpectedAmortizationExpenseRelatedToOtherFiniteLivedIntangibleAssetsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the estimated aggregate amortization expense related to other finite lived intangible assets for each of the five succeeding fiscal years.", "label": "Schedule of Expected Amortization Expense Related to Other Finite Lived Intangible Assets [Table Text Block]", "terseLabel": "Other Finite Lived Intangible Assets Estimated Amortization Expense (Table)" } } }, "localname": "ScheduleOfExpectedAmortizationExpenseRelatedToOtherFiniteLivedIntangibleAssetsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfFairValueAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets and liabilities), and a description of where those gains or losses included in earnings (or changes in net assets and liabilities) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of asset or liability.", "label": "Schedule of Fair Value, Assets, Liabilities, Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]", "terseLabel": "Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Table)" } } }, "localname": "ScheduleOfFairValueAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfInvestmentGainsAndLossesTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Summarization of investment gains and losses, such as realized and unrealized gains and losses, and other-than-temporary impairment losses.", "label": "Schedule of Investment Gains and Losses [Table]" } } }, "localname": "ScheduleOfInvestmentGainsAndLossesTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails" ], "xbrltype": "stringItemType" }, "pfg_ScheduleOfLeaseLiabilityMaturityTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of payments due by period for lease obligations.", "label": "Schedule of Lease, Liability, Maturity [Table Text Block]", "terseLabel": "Future Payments Due by Period for Lease Obligations (Table)" } } }, "localname": "ScheduleOfLeaseLiabilityMaturityTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfLeasesOfLesseeWeightedAverageRemainingTermAndWeightedAverageDiscountRateTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of weighted-average remaining lease terms and weighted-average discount rates for operating leases and finance leases of lessee.", "label": "Schedule of Leases of Lessee, Weighted-Average Remaining Term and Weighted-Average Discount Rate [Table Text Block]", "terseLabel": "Weighted-Average Remaining Lease Term and Weighted-Average Discount Rates (Table)" } } }, "localname": "ScheduleOfLeasesOfLesseeWeightedAverageRemainingTermAndWeightedAverageDiscountRateTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of summarized balance sheet information for unconsolidated entities in which the company has a minority interest.", "label": "Schedule of Minority Interests in Unconsolidated Entities, Balance Sheet [Table Text Block]", "terseLabel": "Minority Interests in Unconsolidated Entities-Balance Sheet (Table)" } } }, "localname": "ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfMinorityInterestsInUnconsolidatedEntitiesIncomeStatementTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of summarized income statement information for unconsolidated entities in which the company has a minority interest.", "label": "Schedule of Minority Interests in Unconsolidated Entities, Income Statement [Table Text Block]", "terseLabel": "Minority Interests in Unconsolidated Entities-Income Statement (Table)" } } }, "localname": "ScheduleOfMinorityInterestsInUnconsolidatedEntitiesIncomeStatementTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfNetDeferredTaxesByJurisdictionTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of net deferred income tax assets and liabilities by jurisdiction.", "label": "Schedule of Net Deferred Taxes by Jurisdiction [Text Block]", "terseLabel": "Net Deferred Income Taxes by Jurisdiction (Table)" } } }, "localname": "ScheduleOfNetDeferredTaxesByJurisdictionTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfNetPeriodicBenefitCostAssumptionsUsedTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the net periodic benefit cost, including assumed discount rate, expected long-term rate of return on plan assets, and rate of compensation increase.", "label": "Schedule of Net Periodic Benefit Cost Assumptions Used [Table Text Block]", "terseLabel": "Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Table)" } } }, "localname": "ScheduleOfNetPeriodicBenefitCostAssumptionsUsedTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure related to unrealized gains and losses on available-for-sale securities, which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. This disclosure includes information about the cumulative net unrealized gains/losses on fixed maturities available-for-sale, equity securities available-for-sale and derivative instruments net of adjustments related to policy acquisition costs, sales inducements, unearned revenue reserves, changes in policyholder benefits and claims and applicable income taxes.", "label": "Schedule of Net Unrealized Gains, Losses, Available-for-Sale Securities and Derivative Instruments [Table Text Block]", "terseLabel": "Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Table)" } } }, "localname": "ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfOtherComprehensiveIncomeLossTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of components of other comprehensive income (loss) including: deferred gains or losses on qualifying hedges, unrealized holding gains or losses on available-for-sale securities, minimum pension liability, and cumulative translation adjustment. Discloses the pre-tax, tax, and after-tax amounts of the activity for each of these components.", "label": "Schedule of Other Comprehensive Income (Loss) [Table Text Block]", "terseLabel": "Other Comprehensive Income (Loss) (Table)" } } }, "localname": "ScheduleOfOtherComprehensiveIncomeLossTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfOtherThanTemporaryImpairmentLossesNetOfRecoveriesTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of total other-than-temporary impairment losses, net of recoveries from the sale of previously impaired securities, for available-for-sale securities.", "label": "Schedule of Other-than-temporary Impairment Losses, Net of Recoveries [Table Text Block]", "terseLabel": "Other-Than-Temporary Impairment Losses, Net of Recoveries (Table)" } } }, "localname": "ScheduleOfOtherThanTemporaryImpairmentLossesNetOfRecoveriesTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the identification, description, and amounts of all significant reconciling items in the reconciliation of (1) operating revenues from reportable segments to consolidated revenues; (2) pre-tax operating earnings from reportable segments to consolidated income before income taxes; and (3) consolidated net realized capital gains (losses) to pre-tax net realized capital gains (losses), as adjusted, which includes the impacts of specific adjustments related to net realized capital gains (losses).", "label": "Schedule of Reconciliation of Operating Revenue and Profit (Loss) from Segments to Consolidated [Table Text Block]", "terseLabel": "Reconciliation of Operating Revenues and Pre-tax Operating Earnings (Losses) by Segment (Table)" } } }, "localname": "ScheduleOfReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfResidentialMortgageLoansCreditQualityIndicatorsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure related to residential mortgage loans by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but are not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics.", "label": "Schedule of Residential Mortgage Loans Credit Quality Indicators [Table Text Block]", "terseLabel": "Performing and Non-Performing Residential Mortgage Loans (Table)" } } }, "localname": "ScheduleOfResidentialMortgageLoansCreditQualityIndicatorsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfStatutoryAccountingPracticesStatutoryNetIncomeAndSurplusTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of statutory net income and statutory surplus of the entity.", "label": "Schedule of Statutory Accounting Practices, Statutory Net Income and Surplus [Table Text Block]", "terseLabel": "Statutory Net Income and Statutory Capital and Surplus of Principal Life (Table)" } } }, "localname": "ScheduleOfStatutoryAccountingPracticesStatutoryNetIncomeAndSurplusTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the overall target allocation of plan assets of pension plans and/or other employee benefit plans by asset category.", "label": "Schedule of Target Allocation of Plan Assets [Table Text Block]", "terseLabel": "Target Asset Allocation (Table)" } } }, "localname": "ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "pfg_ScheduleOfUnconsolidatedVariableInterestEntityAssetsMaximumExposureTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of carrying amount and maximum loss exposure for investments in securities issued by unconsolidated variable interest entities.", "label": "Schedule of Unconsolidated Variable Interest Entity, Assets Maximum Exposure [Table Text Block]", "terseLabel": "Asset Carrying Value and Maximum Loss Exposure of Unconsolidated Variable Interest Entities (Table)" } } }, "localname": "ScheduleOfUnconsolidatedVariableInterestEntityAssetsMaximumExposureTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesTables" ], "xbrltype": "textBlockItemType" }, "pfg_SegmentCorporateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Segment that manages the assets representing capital that has not been allocated to any other segment.", "label": "Segment Corporate [Member]", "terseLabel": "Corporate" } } }, "localname": "SegmentCorporateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SegmentGeographicalAreaEliminationsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Eliminations between geographical areas within an operating segment.", "label": "Segment Geographical Area Eliminations [Member]", "terseLabel": "Geographical Eliminations" } } }, "localname": "SegmentGeographicalAreaEliminationsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "pfg_SegmentIncomeTaxExpenseBenefit": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails": { "order": 1.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to operating earnings.", "label": "Segment Income Tax Expense (Benefit)", "terseLabel": "Total segment income tax expense (benefit) from operating earnings (losses)" } } }, "localname": "SegmentIncomeTaxExpenseBenefit", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentPrincipalGlobalInvestorsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Segment that provides asset management services to asset accumulation business, insurance operations, the Corporate segment and third-party clients.", "label": "Segment Principal Global Investors [Member]", "terseLabel": "Principal Global Investors" } } }, "localname": "SegmentPrincipalGlobalInvestorsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SegmentPrincipalInternationalMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Segment that has operations in countries other than the U.S. with large middle classes, favorable demographics and growing long-term savings, ideally with defined contribution markets.", "label": "Segment Principal International [Member]", "terseLabel": "Principal International" } } }, "localname": "SegmentPrincipalInternationalMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SegmentReportingInformationEarningsAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 3.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Aggregate earnings recognized during the period for adjustments related to equity method investments and noncontrolling interest.", "label": "Segment Reporting Information, Earnings Adjustments Related to Equity Method Investments and Noncontrolling Interest", "terseLabel": "Earnings adjustments related to equity method investments and noncontrolling interest" } } }, "localname": "SegmentReportingInformationEarningsAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 1.0, "parentTag": "pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments", "weight": 1.0 }, "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 2.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Net realized capital gains (losses) net of recognition of deferred front-end fee revenues for sales charges on retirement products and services and certain market value adjustments to fee revenues. It excludes periodic settlements and accruals on derivatives not designated as hedging instruments.", "label": "Segment Reporting Information, Net Realized Capital Gains (Losses)", "terseLabel": "Net realized capital gains (losses), net of related revenue adjustments", "totalLabel": "Net realized capital gains (losses), net of related revenue adjustments" } } }, "localname": "SegmentReportingInformationNetRealizedCapitalGainsLosses", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationOtherAdjustmentsPretax": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 4.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The pre-tax impact of specific transactions that are not recurring in nature and that management does not believe are indicative of overall operating trends.", "label": "Segment Reporting Information, Other Adjustments, Pre-tax", "terseLabel": "Pre-tax other adjustments" } } }, "localname": "SegmentReportingInformationOtherAdjustmentsPretax", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationOtherAfterTaxAdjustmentsTaxEffect": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails": { "order": 3.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Adjustment for the income tax effect of pre-tax other adjustments.", "label": "Segment Reporting Information, Other After-Tax Adjustments Tax Effect", "terseLabel": "Tax benefit related to other after-tax adjustments" } } }, "localname": "SegmentReportingInformationOtherAfterTaxAdjustmentsTaxEffect", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationOtherAfterTaxAdjustmentsTaxEffectTaxCutsAndJobsActOf2017": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of the adjustment for the income tax effect of other after-tax adjustments that relates to the Tax Cuts and Jobs Act of 2017.", "label": "Segment Reporting Information, Other After-Tax Adjustments Tax Effect, Tax Cuts and Jobs Act of 2017", "negatedLabel": "Tax benefit associated with the U.S. tax reform" } } }, "localname": "SegmentReportingInformationOtherAfterTaxAdjustmentsTaxEffectTaxCutsAndJobsActOf2017", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 2.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Pre-tax net realized capital gains (losses) are net of related changes in the amortization pattern of deferred acquisition costs and related actuarial balances, recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and services, amortization of hedge accounting book value adjustments for certain discontinued hedges, net realized capital gains and losses distributed, noncontrolling interest capital gains and losses, certain adjustments related to seed money and certain market value adjustments to fee revenues. Pre-tax net realized capital gains (losses), as adjusted, exclude periodic settlements and accruals on derivative instruments not designated as hedging instruments and exclude certain market value adjustments of embedded derivatives and realized capital gains (losses) associated with our exited group medical insurance business.", "label": "Segment Reporting Information, Pre-tax Net Realized Capital Gains (Losses) Net of Adjustments", "totalLabel": "Pre-tax net realized capital gains (losses), as adjusted", "verboseLabel": "Pre-tax net realized capital gains (losses), as adjusted" } } }, "localname": "SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationRevenueAdjustmentsRelatedToEquityMethodInvestments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": 3.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Aggregate revenue recognized during the period for adjustments related to equity method investments.", "label": "Segment Reporting Information, Revenue Adjustments Related to Equity Method Investments", "terseLabel": "Adjustments related to equity method investments" } } }, "localname": "SegmentReportingInformationRevenueAdjustmentsRelatedToEquityMethodInvestments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentReportingInformationTaxExpenseBenefitAssociatedWithCertainAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails": { "order": 4.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Tax expense (benefit) recognized during the period associated with certain adjustments related to equity method investments and noncontrolling interest.", "label": "Segment Reporting Information, Tax Expense (Benefit) Associated with Certain Adjustments Related to Equity Method Investments and Noncontrolling Interest", "verboseLabel": "Tax expense (benefit) associated with certain adjustments related to equity method investments and noncontrolling interest" } } }, "localname": "SegmentReportingInformationTaxExpenseBenefitAssociatedWithCertainAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SegmentRetirementAndIncomeSolutionsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Segment that provides retirement and related financial products and services primarily to businesses, their employees and other individuals.", "label": "Segment Retirement And Income Solutions [Member]", "terseLabel": "Retirement and Income Solutions" } } }, "localname": "SegmentRetirementAndIncomeSolutionsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SegmentUSInsuranceSolutionsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Segment that provides specialty benefits insurance, which consists of group dental and vision insurance, individual and group disability insurance, group life insurance and non-medical fee-for-service claims administration, and individual life insurance throughout the U.S.", "label": "Segment U S Insurance Solutions [Member]", "terseLabel": "U.S. Insurance Solutions" } } }, "localname": "SegmentUSInsuranceSolutionsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SeniorNotesDue2028Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Senior Notes due 2028.", "label": "Senior Notes Due2028 [Member]", "terseLabel": "Senior Notes due 2028" } } }, "localname": "SeniorNotesDue2028Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_SeniorNotesDue2048Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Senior Notes due 2048.", "label": "Senior Notes Due2048 [Member]", "terseLabel": "Senior Notes due 2048" } } }, "localname": "SeniorNotesDue2048Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "pfg_SeparateAccountAssetsMeasurementInput": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Value of input used to measure separate account assets.", "label": "Separate Account Assets, Measurement Input", "terseLabel": "Separate account assets, Input" } } }, "localname": "SeparateAccountAssetsMeasurementInput", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "decimalItemType" }, "pfg_SeparateAccountAssetsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Assets held by the Entity for the benefit of separate account policyholders.", "label": "Separate Account Assets [Member]", "terseLabel": "Separate account assets" } } }, "localname": "SeparateAccountAssetsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "domainItemType" }, "pfg_SeparateAccountLiabilitiesFairValueDisclosure": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents investment-type separate account liabilities that do not have significant insurance risk.", "label": "Separate Account Liabilities, Fair Value Disclosure", "negatedLabel": "Separate account liabilities" } } }, "localname": "SeparateAccountLiabilitiesFairValueDisclosure", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "pfg_SeparateAccountWithSharesOfPrincipalFinancialGroupStock": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents the value of a separate account that primarily includes shares of Principal Financial Group, Inc. stock that were allocated and issued to eligible participants of qualified employee benefit plans administered as part of the policy credits issued under the 2001 demutualization.", "label": "Separate Account with Shares of Principal Financial Group Stock", "terseLabel": "Separate account that primarily includes shares of Principal Financial Group, Inc. stock that were allocated and issued to eligible participants of qualified employee benefit plans as part of the 2001 demutualization" } } }, "localname": "SeparateAccountWithSharesOfPrincipalFinancialGroupStock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsLowerMultipleOfInitialTargetBasedOnPerformance": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The lower limit multiple of initial target awards which will be used to determine the actual number of shares to be awarded at the end of each performance period for performance-based awards.", "label": "Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Lower Multiple of Target Based on Performance", "terseLabel": "Lower limit multiple of initial target awards (as a percent)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsLowerMultipleOfInitialTargetBasedOnPerformance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "percentItemType" }, "pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUpperLimitMultipleOfInitialTargetBasedOnPerformance": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The upper limit multiple of initial target awards which will be used to determine the actual number of shares to be awarded at the end of each performance period for performance-based awards.", "label": "Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Upper Limit Multiple of Target, Based on Performance", "terseLabel": "Upper limit multiple of initial target awards (as a percent)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUpperLimitMultipleOfInitialTargetBasedOnPerformance", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "percentItemType" }, "pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesThatWillBeGranted": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the number of shares (or other type of equity) that will be granted under specified plans.", "label": "Share-based Compensation Arrangement by Share-based Payment Award Number of Shares that will be Granted", "terseLabel": "Number of shares that will be granted" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesThatWillBeGranted", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "sharesItemType" }, "pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The number of years in the performance period for the purpose of setting performance goals for a share-based compensation plan.", "label": "Share-Based Compensation Arrangement by Share-Based Payment Award Performance Goals, In Years", "terseLabel": "Performance period for goals" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "durationItemType" }, "pfg_ShareBasedCompensationArrangementShareBasedPaymentAwardAmountCapitalized": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Represents the compensation cost capitalized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees and certain agents.", "label": "Share-Based Compensation Arrangement, Share-Based Payment Award, Amount Capitalized", "terseLabel": "Capitalized as part of an asset" } } }, "localname": "ShareBasedCompensationArrangementShareBasedPaymentAwardAmountCapitalized", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_ShortDurationInsuranceContractsDiscountedLiabilitiesTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of information about liabilities for unpaid claims that are presented at present value for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts Discounted Liabilities [Table Text Block]", "terseLabel": "Discounting (Table)" } } }, "localname": "ShortDurationInsuranceContractsDiscountedLiabilitiesTableTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "pfg_SingleClientSeparateAccountInvestmentsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Pension plan assets comprising single client separate accounts.", "label": "Single Client Separate Account Investments [Member]", "terseLabel": "Single client separate account investments" } } }, "localname": "SingleClientSeparateAccountInvestmentsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_SingleClientSeparateAccountsInvestedInPooledSeparateAccountMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Single-client separate accounts invested in a money market pooled separate account.", "label": "Single Client Separate Accounts Invested In Pooled Separate Account [Member]", "terseLabel": "Pooled separate account investment" } } }, "localname": "SingleClientSeparateAccountsInvestedInPooledSeparateAccountMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_SingleNameCreditDefaultSwapsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A type of swap transaction used as a credit derivative, where the underlying assets reference a single name or reference security.", "label": "Single Name Credit Default Swaps [Member]", "terseLabel": "Single name credit default swaps" } } }, "localname": "SingleNameCreditDefaultSwapsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "pfg_SouthAtlanticMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the South Atlantic region of the United States.", "label": "South Atlantic [Member]", "terseLabel": "South Atlantic" } } }, "localname": "SouthAtlanticMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_SponsoredInvestmentFundsRelatedAdjustments": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 5.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Adjustment to move amounts reported in net investment income to net realized capital gains (losses) for segment profit (loss) reporting related to sponsored investment funds.", "label": "Sponsored Investment Funds Related Adjustments", "terseLabel": "Adjustments related to sponsored investment funds" } } }, "localname": "SponsoredInvestmentFundsRelatedAdjustments", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_StandardPoorsAMinusAndAboveRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A- credit rating and above as defined by the external credit rating agency, Standard and Poor's.", "label": "Standard Poors A Minus And Above Rating [Member]", "terseLabel": "A- and above" } } }, "localname": "StandardPoorsAMinusAndAboveRatingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_StandardPoorsBBBPlusThruBBBMinusRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "BBB+ credit rating through BBB- credit rating as defined by the external credit rating agency, Standard and Poor's.", "label": "Standard Poors B B B Plus Thru B B B Minus Rating [Member]", "terseLabel": "BBB+ thru BBB-" } } }, "localname": "StandardPoorsBBBPlusThruBBBMinusRatingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_StandardPoorsBBPlusThruBBMinusRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "BB+ credit rating through BB- credit rating as defined by the external credit rating agency, Standard and Poor's.", "label": "Standard Poors B B Plus Thru B B Minus Rating [Member]", "terseLabel": "BB+ thru BB-" } } }, "localname": "StandardPoorsBBPlusThruBBMinusRatingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_StandardPoorsBPlusAndBelowRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "B+ credit rating and below as defined by the external credit rating agency, Standard and Poor's.", "label": "Standard Poors B Plus And Below Rating [Member]", "terseLabel": "B+ and below" } } }, "localname": "StandardPoorsBPlusAndBelowRatingMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "pfg_StatutoryAccountingPracticesStatutoryNetIncomeAndSurplusAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Statutory Accounting Practices, Statutory Net Income and Surplus [Abstract]", "terseLabel": "Statutory disclosures" } } }, "localname": "StatutoryAccountingPracticesStatutoryNetIncomeAndSurplusAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "stringItemType" }, "pfg_StatutoryInsuranceFinancialInformationDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Statutory Insurance Financial Information" } } }, "localname": "StatutoryInsuranceFinancialInformationDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_StatutoryInsuranceFinancialInformationDisclosureTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Discloses how the entity's reporting under GAAP as of the balance sheet date differs from the results based on prescribed and permitted accounting practices of the state or country of domicile in which a relevant statutory filing is made, or differences in results based on the National Association of Insurance Commissioners (NAIC) prescribed practices, or a combination thereof. Describes the accounting practices used and the related monetary effect on statutory surplus, net income and risk-based capital. If an insurance enterprise's risk-based capital would have triggered a regulatory event had it not used a permitted practice, that fact should be disclosed in the financial statements. Permitted statutory accounting practices include practices not prescribed but allowed by the domiciliary state insurance department regulatory authority.", "label": "Statutory Insurance Financial Information Disclosure [Text Block]", "terseLabel": "Statutory Insurance Financial Information" } } }, "localname": "StatutoryInsuranceFinancialInformationDisclosureTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformation" ], "xbrltype": "textBlockItemType" }, "pfg_StatutoryReservesAssumedByAffiliatedReinsuranceSubsidiaries": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of statutory reserves assumed by affiliated reinsurance subsidiaries.", "label": "Statutory Reserves Assumed by Affiliated Reinsurance Subsidiaries", "terseLabel": "Statutory reserves assumed by affiliated reinsurance subsidiaries" } } }, "localname": "StatutoryReservesAssumedByAffiliatedReinsuranceSubsidiaries", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "pfg_StockBasedCompensation": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The adjustments to additional paid-in capital during the period associated with equity-based awards as a result of any share-based compensation plan other than an employee stock ownership plan (ESOP). This item also includes the impact of common stock dividend equivalents earned on certain unvested equity-based awards, which are charged to retained earnings.", "label": "Stock-Based Compensation", "terseLabel": "Stock-based compensation" } } }, "localname": "StockBasedCompensation", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "pfg_StockBasedCompensationPlans2014DirectorsStockPlan2005DirectorsStockPlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Specific share-based compensation plans under which stock awards can be granted to members of the entity's Board of Directors.", "label": "Stock Based Compensation Plans2014 Directors Stock Plan2005 Directors Stock Plan [Member]", "terseLabel": "2014 Directors Stock Plan and 2005 Directors Stock Plan" } } }, "localname": "StockBasedCompensationPlans2014DirectorsStockPlan2005DirectorsStockPlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "domainItemType" }, "pfg_StockBasedCompensationPlans2014StockIncentivePlanAmendedAndRestated2010StockIncentivePlanStockIncentivePlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Specific share-based compensation plans under which stock awards can be or have previously been granted to employees and agents.", "label": "Stock Based Compensation Plans2014 Stock Incentive Plan Amended And Restated2010 Stock Incentive Plan Stock Incentive Plan [Member]", "terseLabel": "2014 Stock Incentive Plan, Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan" } } }, "localname": "StockBasedCompensationPlans2014StockIncentivePlanAmendedAndRestated2010StockIncentivePlanStockIncentivePlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "domainItemType" }, "pfg_StockBasedCompensationPlansAmendedAndRestated2010StockIncentivePlan2005DirectorsStockPlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Specific share-based compensation plans under which stock awards were previously granted but no longer will be granted as of May 2014.", "label": "Stock Based Compensation Plans Amended And Restated2010 Stock Incentive Plan2005 Directors Stock Plan [Member]", "terseLabel": "Amended and Restated 2010 Stock Incentive Plan and 2005 Directors Stock Plan" } } }, "localname": "StockBasedCompensationPlansAmendedAndRestated2010StockIncentivePlan2005DirectorsStockPlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "domainItemType" }, "pfg_StockBasedCompensationPlansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Share-based compensation plans under which stock awards can be granted. This includes the stock incentive plans as well as the employee stock purchase plan and long-term performance plan.", "label": "Stock Based Compensation Plans [Member]", "terseLabel": "Stock-Based Compensation Plans" } } }, "localname": "StockBasedCompensationPlansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "domainItemType" }, "pfg_StockBasedCompensationPlansStockIncentivePlanDirectorsStockPlanMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Specific share-based compensation plans under which stock awards were previously granted.", "label": "Stock Based Compensation Plans Stock Incentive Plan Directors Stock Plan [Member]", "terseLabel": "Stock Incentive Plan and Directors Stock Plan" } } }, "localname": "StockBasedCompensationPlansStockIncentivePlanDirectorsStockPlanMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "domainItemType" }, "pfg_StockIncentivePlansMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Share-based compensation plans under which stock incentive awards can be granted.", "label": "Stock Incentive Plans [Member]", "terseLabel": "2014 Stock Incentive Plan and 2014 Directors Stock Plan" } } }, "localname": "StockIncentivePlansMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsegmentIndividualLifeInsuranceMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Business that provides a variety of individual life insurance products, including universal and variable universal life insurance and term life insurance.", "label": "Subsegment Individual Life Insurance [Member]", "terseLabel": "Individual Life insurance" } } }, "localname": "SubsegmentIndividualLifeInsuranceMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsegmentRetirementAndIncomeSolutionsFeeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Business that provides 1) a wide variety of investment and administrative products for defined contribution pension plans, defined benefit pension plans, nonqualified executive benefit plans and ESOPs and 2) variable annuities to individuals and pension plans.", "label": "Subsegment Retirement And Income Solutions Fee [Member]", "terseLabel": "Retirement and Income Solutions - Fee" } } }, "localname": "SubsegmentRetirementAndIncomeSolutionsFeeMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsegmentRetirementAndIncomeSolutionsSpreadMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Business that provides 1) fixed annuities to individuals and pension plans 2) guaranteed investment contracts, funding agreements and other investment only products, 3) single premium group annuities and other products that offer a current or future specific income amount that is fully guaranteed and 4) banking services.", "label": "Subsegment Retirement And Income Solutions Spread [Member]", "terseLabel": "Retirement and Income Solutions - Spread" } } }, "localname": "SubsegmentRetirementAndIncomeSolutionsSpreadMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsegmentSpecialtyBenefitsInsuranceMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Business that provides group dental, vision and life insurance, as well as individual and group disability insurance.", "label": "Subsegment Specialty Benefits Insurance [Member]", "terseLabel": "Specialty Benefits insurance" } } }, "localname": "SubsegmentSpecialtyBenefitsInsuranceMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsegmentUSInsuranceSolutionsEliminationsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Intra-segment activities between the different U.S. Insurance Solutions businesses.", "label": "Subsegment U S Insurance Solutions Eliminations [Member]", "terseLabel": "U.S. Insurance Solutions Eliminations" } } }, "localname": "SubsegmentUSInsuranceSolutionsEliminationsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsidiariesPrincipalFinancialServicesAndOtherMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "All subsidiaries of Principal Financial Group, Inc. except Principal Life Insurance Company.", "label": "Subsidiaries Principal Financial Services And Other [Member]", "terseLabel": "Principal Financial Services, Inc. and other subsidiaries combined" } } }, "localname": "SubsidiariesPrincipalFinancialServicesAndOtherMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsidiariesPrincipalLifeInsuranceAndOtherConsolidateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "All subsidiaries of Principal Financial Group, Inc. except Principal Financial Services, Inc.", "label": "Subsidiaries Principal Life Insurance And Other Consolidate [Member]", "terseLabel": "Principal Life Insurance Company and other subsidiaries combined" } } }, "localname": "SubsidiariesPrincipalLifeInsuranceAndOtherConsolidateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsidiariesPrincipalLifeInsuranceCompanyMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The primary insurance company of Principal Financial Group, Inc.", "label": "Subsidiaries Principal Life Insurance Company [Member]", "terseLabel": "Principal Life Insurance Company only" } } }, "localname": "SubsidiariesPrincipalLifeInsuranceCompanyMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "domainItemType" }, "pfg_SubsidiaryPrincipalFinancialServicesConsolidateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The direct wholly owned subsidiary of Principal Financial Group, Inc.", "label": "Subsidiary Principal Financial Services Consolidate [Member]", "terseLabel": "Principal Financial Services, Inc. only" } } }, "localname": "SubsidiaryPrincipalFinancialServicesConsolidateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "pfg_SummaryOfWeightedAverageRemainingContractualLivesForStockOptionsOutstandingAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Summary of Weighted Average Remaining Contractual Lives for Stock Options Outstanding [Abstract]", "terseLabel": "Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices" } } }, "localname": "SummaryOfWeightedAverageRemainingContractualLivesForStockOptionsOutstandingAbstract", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "stringItemType" }, "pfg_TaxBenefitsRealizedFromAwardsOrUnitsPaidOut": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Disclosure of the aggregate tax benefit realized from the payout of awards or units during the period.", "label": "Tax Benefits Realized from Awards or Units Paid Out", "terseLabel": "Tax benefits realized for the tax deductions from awards or units paid out" } } }, "localname": "TaxBenefitsRealizedFromAwardsOrUnitsPaidOut", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TaxBenefitsRealizedFromSettlement": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Disclosure of the aggregate tax benefit realized during the period from the settlement of share-based payment arrangements.", "label": "Tax Benefits Realized from Settlement", "terseLabel": "Tax benefits realized from the settlement of share-based payment arrangements" } } }, "localname": "TaxBenefitsRealizedFromSettlement", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TermOfContingentFundingAgreement": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Term of a contingent funding agreement, in 'PnYnMnDTnHnMnS' format.", "label": "Term of Contingent Funding Agreement", "terseLabel": "Term of contingent funding agreement" } } }, "localname": "TermOfContingentFundingAgreement", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "durationItemType" }, "pfg_TerminalEarningsBeforeInterestTaxesDepreciationAndAmortizationMultipleMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input using the rate used to estimate the terminal earnings before interest, taxes, depreciation and amortization multiple.", "label": "Terminal Earnings Before Interest Taxes Depreciation And Amortization Multiple [Member]", "terseLabel": "Terminal earnings before interest, taxes, depreciation and amortization multiple" } } }, "localname": "TerminalEarningsBeforeInterestTaxesDepreciationAndAmortizationMultipleMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "pfg_ThresholdEquityExcludingOCIAndNoncontrollingInterestForAutomaticExerciseOfOption": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The minimum level of shareholders' equity, excluding accumulated other comprehensive income and noncontrolling interest, below which automatic exercise of the option is triggered.", "label": "Threshold Equity Excluding A O C I and Noncontrolling Interest for Automatic Exercise of Option", "terseLabel": "Minimum shareholders' equity excluding AOCI and NCI, to avoid automatic exercise of options" } } }, "localname": "ThresholdEquityExcludingOCIAndNoncontrollingInterestForAutomaticExerciseOfOption", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TotalAmountRecoverableFromReinsurers": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The total amount recoverable from reinsurers includes net ceded reinsurance recoverables related to claims that have been received and reserves ceded to reinsurers; however, it does not reflect potentially offsetting impacts of collateral.", "label": "Total Amount Recoverable From Reinsurers", "terseLabel": "Total amount recoverable from reinsurers" } } }, "localname": "TotalAmountRecoverableFromReinsurers", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TotalAssetsUnconsolidatedMoneyMarketMutualFund": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Total assets held by money market mutual funds that are not consolidated by the entity as the money market funds are registered under Rule 2a-7 of the Investment Company Act of 1940 or are similar unregistered funds.", "label": "Total Assets Unconsolidated Money Market Mutual Fund", "terseLabel": "Total assets of unconsolidated money market mutual funds" } } }, "localname": "TotalAssetsUnconsolidatedMoneyMarketMutualFund", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TotalLeaseLiabilities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Present value of lessee's discounted obligation for lease payments.", "label": "Total Lease Liabilities", "totalLabel": "Total lease liabilities", "verboseLabel": "Present value of lease liabilities" } } }, "localname": "TotalLeaseLiabilities", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TotalLeaseRightOfUseAssets": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's right to use underlying asset under lease.", "label": "Total Lease Right-of-Use Assets", "totalLabel": "Total lease assets" } } }, "localname": "TotalLeaseRightOfUseAssets", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_TradingSecuritiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Investment in securities measured at fair value with change in fair value recognized in net income (trading).", "label": "Trading Securities [Member]", "terseLabel": "Trading" } } }, "localname": "TradingSecuritiesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_TreasuryStockAcquiredRepurchaseAuthorizationAmount": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This element represents the maximum amount authorized for share repurchase by the board of directors.", "label": "Treasury Stock Acquired, Repurchase Authorization Amount", "terseLabel": "Share repurchase program, maximum authorized amount (in dollars)" } } }, "localname": "TreasuryStockAcquiredRepurchaseAuthorizationAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_UnconsolidatedVariableInterestEntityAssetsTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A tabular comparison of the carrying amount and maximum loss exposure for investments in securities issued by unconsolidated variable interest entities.", "label": "Investment in Unconsolidated Variable Interest Entities [Table]" } } }, "localname": "UnconsolidatedVariableInterestEntityAssetsTable", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "pfg_UnconsolidatedVariableInterestEntityLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Unconsolidated Variable Interest Entity [Line Items]", "terseLabel": "Unconsolidated Variable Interest Entity disclosures" } } }, "localname": "UnconsolidatedVariableInterestEntityLineItems", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "pfg_UndistributedForeignEarningsWithoutDeferredTaxesProvided": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Accumulated but undistributed earnings of foreign subsidiaries considered to be indefinitely reinvested in the business such that it is not practical to determine the amount of unrecognized deferred tax liability that would arise if these earnings were remitted due to foreign tax credits and exclusions that may become available at the time of remittance.", "label": "Undistributed Foreign Earnings Without Deferred Taxes Provided", "terseLabel": "Accumulated but undistributed earnings from operations of foreign subsidiaries for which U.S. federal and state deferred income taxes have not been provided" } } }, "localname": "UndistributedForeignEarningsWithoutDeferredTaxesProvided", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "pfg_UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetInvestmentIncome": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), accounted for as net investment income.", "label": "Unrealized Gains (Losses) on Equity Securities, FV-NI, Reported in Net Investment Income", "terseLabel": "Unrealized gains (losses) on equity securities reported in net investment income" } } }, "localname": "UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetInvestmentIncome", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_UnrealizedGainsLossesOnTradingSecuritiesReportedInNetInvestmentIncome": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized gain (loss) on equity securities classified as trading, accounted for as net investment income.", "label": "Unrealized Gains (Losses) on Trading Securities, Reported in Net Investment Income", "terseLabel": "Unrealized gains (losses) on equity securities, trading reported in net investment income" } } }, "localname": "UnrealizedGainsLossesOnTradingSecuritiesReportedInNetInvestmentIncome", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_UnsecuredLineOfCreditMaturingSeptember2019Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Unsecured line of credit entered into by the entity with maturity in September 2019.", "label": "Unsecured Line Of Credit Maturing September2019 [Member]", "terseLabel": "Unsecured line of credit maturing September 2019" } } }, "localname": "UnsecuredLineOfCreditMaturingSeptember2019Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_UnsecuredLineOfCreditMaturingSeptember2020Member": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Unsecured line of credit entered into by the entity with maturity in September 2020.", "label": "Unsecured Line Of Credit Maturing September2020 [Member]", "terseLabel": "Unsecured line of credit maturing September 2020" } } }, "localname": "UnsecuredLineOfCreditMaturingSeptember2020Member", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_UnsecuredLineOfCreditMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time, and under which the borrowings are uncollateralized.", "label": "Unsecured Line Of Credit [Member]", "terseLabel": "Unsecured lines of credit" } } }, "localname": "UnsecuredLineOfCreditMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "pfg_ValueOfAssetsReceivedInKindForPensionRiskTransferTransactions": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Value of assets received in kind in non-cash transfer of pension risk transaction.", "label": "Value Of Assets Received In Kind For Pension Risk Transfer Transactions", "terseLabel": "Assets received in kind for pension risk transfer transactions" } } }, "localname": "ValueOfAssetsReceivedInKindForPensionRiskTransferTransactions", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "pfg_VariableInterestEntitiesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "No definition available.", "label": "Variable Interest Entities" } } }, "localname": "VariableInterestEntitiesDisclosureAbstract", "nsuri": "http://principal.com/20191231", "xbrltype": "stringItemType" }, "pfg_VariableInterestEntitiesDisclosureTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The entire disclosure of variable interest entities (VIE), including, but not limited to the nature, purpose, size, and activities of the VIE, the carrying amount and classification of consolidated assets that are collateral for the VIE's obligations, lack of recourse if creditors (or beneficial interest holders) of a consolidated VIE have no recourse to the general credit of the primary beneficiary. An enterprise that holds a significant variable interest in a VIE but is not the primary beneficiary may disclose the nature of its involvement with the VIE and when that involvement began, the nature, purpose, size, and activities of the VIE and the enterprise's maximum exposure to loss as a result of its involvement with the VIE.", "label": "Variable Interest Entities [Text Block]", "terseLabel": "Variable Interest Entities" } } }, "localname": "VariableInterestEntitiesDisclosureTextBlock", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntities" ], "xbrltype": "textBlockItemType" }, "pfg_VariableInterestEntityFullySecuredDebtOfInternationalRealEstateFundsIncludedInMaximumLossExposureAmount": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of debt of managed international rest estate funds that is fully secured by assets whose value exceeds the amount of the debt, but also includes recourse to the investment manager, included in the reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).", "label": "Variable Interest Entity, Fully Secured Debt of International Real Estate Funds Included in Maximum Loss Exposure, Amount", "terseLabel": "Fully secured debt of international real estate funds with recourse to the investment manager, included in maximum loss exposure" } } }, "localname": "VariableInterestEntityFullySecuredDebtOfInternationalRealEstateFundsIncludedInMaximumLossExposureAmount", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "monetaryItemType" }, "pfg_VariableInterestEntityPrimaryBeneficiaryCommercialMortgageBackedSecuritiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Consolidated real estate mortgage investment conduit trust (that is a variable interest entity) that issues commercial mortgage-backed securities certificates using the cash flows of underlying commercial mortgages it purchased from the entity.", "label": "Variable Interest Entity Primary Beneficiary Commercial Mortgage Backed Securities [Member]", "terseLabel": "Commercial mortgage-backed securities VIE" } } }, "localname": "VariableInterestEntityPrimaryBeneficiaryCommercialMortgageBackedSecuritiesMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_VariableInterestEntityPrimaryBeneficiaryGrantorTrustsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Consolidated trusts (that are variable interest entities) that separate the cash flows of undated subordinated floating rate notes contributed to them by issuing an interest-only certificate and residual certificate related to each note contributed.", "label": "Variable Interest Entity Primary Beneficiary Grantor Trusts [Member]", "terseLabel": "Grantor trust" } } }, "localname": "VariableInterestEntityPrimaryBeneficiaryGrantorTrustsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_VariableInterestEntityPrimaryBeneficiaryMandatoryRetirementSavingsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Consolidated mandatory retirement savings funds (that are variable interest entities) that may include contributions for voluntary pension savings, voluntary non-pension savings and compensation savings accounts.", "label": "Variable Interest Entity Primary Beneficiary Mandatory Retirement Savings [Member]", "terseLabel": "Mandatory retirement savings funds" } } }, "localname": "VariableInterestEntityPrimaryBeneficiaryMandatoryRetirementSavingsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_VariableInterestEntityPrimaryBeneficiaryRealEstateMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Consolidated real estate limited partnerships and limited liability companies (that are variable interest entities).", "label": "Variable Interest Entity Primary Beneficiary Real Estate [Member]", "terseLabel": "Real estate VIE" } } }, "localname": "VariableInterestEntityPrimaryBeneficiaryRealEstateMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_VariableInterestEntityPrimaryBeneficiarySponsoredInvestmentFundsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Consolidated sponsored investment funds (that are variable interest entities).", "label": "Variable Interest Entity Primary Beneficiary Sponsored Investment Funds [Member]", "terseLabel": "Sponsored investment funds" } } }, "localname": "VariableInterestEntityPrimaryBeneficiarySponsoredInvestmentFundsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "pfg_WMAdvisorsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This element represents the WM Advisors, Inc.", "label": "W M Advisors [Member]", "terseLabel": "WM Advisors, Inc." } } }, "localname": "WMAdvisorsMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "domainItemType" }, "pfg_WestNorthCentralMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the West North Central region of the United States.", "label": "West North Central [Member]", "terseLabel": "West North Central" } } }, "localname": "WestNorthCentralMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_WestSouthCentralMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Represents the West South Central region of the United States.", "label": "West South Central [Member]", "terseLabel": "West South Central" } } }, "localname": "WestSouthCentralMember", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "pfg_YearsInterestPaymentsOnDebtDeferred": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The number of years interest payments on debt can be deferred without resulting in a default.", "label": "Years Interest Payments on Debt Deferred", "terseLabel": "Years interest payments on debt can be deferred" } } }, "localname": "YearsInterestPaymentsOnDebtDeferred", "nsuri": "http://principal.com/20191231", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "durationItemType" }, "srt_ApartmentBuildingMember": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Building containing a number of residential apartments.", "label": "Apartment Building [Member]", "terseLabel": "Apartments" } } }, "localname": "ApartmentBuildingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_AsiaMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Continent of Asia.", "label": "Asia [Member]", "terseLabel": "Asia" } } }, "localname": "AsiaMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "srt_CondensedFinancialInformationOfParentCompanyOnlyDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Schedule II - Condensed Financial Information of Registrant (Parent Only)" } } }, "localname": "CondensedFinancialInformationOfParentCompanyOnlyDisclosureAbstract", "nsuri": "http://fasb.org/srt/2019-01-31", "xbrltype": "stringItemType" }, "srt_CondensedFinancialStatementsCaptionsLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Condensed Financial Statements, Captions [Line Items]" } } }, "localname": "CondensedFinancialStatementsCaptionsLineItems", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "srt_CondensedFinancialStatementsTextBlock": { "auth_ref": [ "r142", "r855", "r859", "r860", "r861", "r862" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for condensed financial statements.", "label": "Condensed Financial Statements [Text Block]", "terseLabel": "Condensed Consolidating Financial Information" } } }, "localname": "CondensedFinancialStatementsTextBlock", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformation" ], "xbrltype": "textBlockItemType" }, "srt_ConsolidatedEntitiesAxis": { "auth_ref": [ "r838", "r848" ], "lang": { "en-US": { "role": { "documentation": "Information by consolidated entity or group of entities.", "label": "Consolidated Entities [Axis]" } } }, "localname": "ConsolidatedEntitiesAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "stringItemType" }, "srt_ConsolidatedEntitiesDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Entity or group of entities consolidated into reporting entity.", "label": "Consolidated Entities [Domain]", "terseLabel": "Consolidated Entities [Domain]" } } }, "localname": "ConsolidatedEntitiesDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "domainItemType" }, "srt_ConsolidationEliminationsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Eliminating entries used in consolidating a parent entity and its subsidiaries.", "label": "Consolidation Eliminations [Member]", "terseLabel": "Eliminations" } } }, "localname": "ConsolidationEliminationsMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "srt_ConsolidationItemsAxis": { "auth_ref": [ "r177", "r188" ], "lang": { "en-US": { "role": { "documentation": "Information by components, eliminations, non-segment corporate-level activity and reconciling items used in consolidating a parent entity and its subsidiaries or its operating segments.", "label": "Consolidation Items [Axis]" } } }, "localname": "ConsolidationItemsAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "srt_ConsolidationItemsDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Components, elimination, non-segment corporate-level activity and reconciling items used in consolidating a parent entity and its subsidiaries or its operating segments.", "label": "Consolidation Items [Domain]", "terseLabel": "Consolidation Items [Domain]" } } }, "localname": "ConsolidationItemsDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "srt_CounterpartyNameAxis": { "auth_ref": [ "r53", "r132", "r863" ], "lang": { "en-US": { "role": { "documentation": "Information by name of counterparty. A counterparty is the other party that participates in a financial transaction. Examples include, but not limited to, the name of the financial institution.", "label": "Counterparty Name [Axis]" } } }, "localname": "CounterpartyNameAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "stringItemType" }, "srt_CreditRatingStandardPoorsAxis": { "auth_ref": [ "r210", "r266", "r267", "r327", "r570" ], "lang": { "en-US": { "role": { "documentation": "Information by Standard and Poor's rating.", "label": "Credit Rating, Standard & Poor's [Axis]" } } }, "localname": "CreditRatingStandardPoorsAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "stringItemType" }, "srt_ExternalCreditRatingStandardPoorsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Credit-ratings as used by Standard & Poor's. Contact Standard & Poor's for a complete list of ratings and their definitions.", "label": "External Credit Rating Standard Poors [Member]", "terseLabel": "External Credit Rating, Standard & Poor's [Domain]" } } }, "localname": "ExternalCreditRatingStandardPoorsMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "srt_HotelMember": { "auth_ref": [ "r362", "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Commercial establishment providing lodging, meal, meeting space and other related service.", "label": "Hotel [Member]", "terseLabel": "Hotel" } } }, "localname": "HotelMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_IndustrialPropertyMember": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Building designed to house industrial operations and provide the necessary conditions for the operation of industrial equipment.", "label": "Industrial Property [Member]", "terseLabel": "Industrial" } } }, "localname": "IndustrialPropertyMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_LatinAmericaMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Region of Latin America.", "label": "Latin America [Member]", "terseLabel": "Latin America" } } }, "localname": "LatinAmericaMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "srt_LifeInsuranceInForceAssumed": { "auth_ref": [ "r742", "r852" ], "calculation": { "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails": { "order": 3.0, "parentTag": "srt_LifeInsuranceInForceNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of life insurance issued and outstanding assumed from other entity, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.", "label": "Life Insurance in Force, Assumed", "terseLabel": "Life insurance in force assumed from other companies" } } }, "localname": "LifeInsuranceInForceAssumed", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "srt_LifeInsuranceInForceCeded": { "auth_ref": [ "r741", "r851" ], "calculation": { "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails": { "order": 2.0, "parentTag": "srt_LifeInsuranceInForceNet", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of life insurance issued and outstanding ceded to other entity, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.", "label": "Life Insurance in Force, Ceded", "terseLabel": "Life insurance in force ceded to other companies" } } }, "localname": "LifeInsuranceInForceCeded", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "srt_LifeInsuranceInForceGross": { "auth_ref": [ "r740", "r850" ], "calculation": { "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails": { "order": 1.0, "parentTag": "srt_LifeInsuranceInForceNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before effect of reinsurance, of life insurance issued and outstanding, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.", "label": "Life Insurance in Force, Gross", "terseLabel": "Life insurance in force gross amount" } } }, "localname": "LifeInsuranceInForceGross", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "srt_LifeInsuranceInForceNet": { "auth_ref": [ "r743", "r853" ], "calculation": { "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after effect of reinsurance, of life insurance issued and outstanding, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.", "label": "Life Insurance in Force, Net", "totalLabel": "Life insurance in force net amount" } } }, "localname": "LifeInsuranceInForceNet", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "srt_LifeInsuranceInForceNetAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Life Insurance in Force, Net [Abstract]", "terseLabel": "Life insurance in force" } } }, "localname": "LifeInsuranceInForceNetAbstract", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "stringItemType" }, "srt_LifeInsuranceInForcePercentageAssumedToNet": { "auth_ref": [ "r744", "r854" ], "lang": { "en-US": { "role": { "documentation": "Percentage of assumed life insurance contract issued and outstanding to life insurance contract issued and outstanding after effect of reinsurance, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.", "label": "Life Insurance in Force, Percentage Assumed to Net", "terseLabel": "Life insurance in force, percentage of amount assumed to net (as a percent)" } } }, "localname": "LifeInsuranceInForcePercentageAssumedToNet", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "percentItemType" }, "srt_LitigationCaseAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by type of judicial proceeding, alternative dispute resolution or claim.", "label": "Litigation Case [Axis]" } } }, "localname": "LitigationCaseAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "srt_LitigationCaseTypeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Judicial proceeding, alternative dispute resolution or claim. For example, but not limited to, name of case, category of litigation, or other differentiating information.", "label": "Litigation Case Type [Domain]", "terseLabel": "Litigation Case [Domain]" } } }, "localname": "LitigationCaseTypeDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "domainItemType" }, "srt_MaximumMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Upper limit of the provided range.", "label": "Maximum [Member]", "terseLabel": "Maximum" } } }, "localname": "MaximumMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "domainItemType" }, "srt_MinimumMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Lower limit of the provided range.", "label": "Minimum [Member]", "terseLabel": "Minimum" } } }, "localname": "MinimumMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "domainItemType" }, "srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Information by type of real estate property.", "label": "Real Estate, Type of Property [Axis]" } } }, "localname": "MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "stringItemType" }, "srt_MortgageLoansOnRealEstateLoanTypeAxis": { "auth_ref": [ "r834", "r847" ], "lang": { "en-US": { "role": { "documentation": "Information by type of loan for investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.", "label": "Mortgage Loans on Real Estate, Loan Type [Axis]" } } }, "localname": "MortgageLoansOnRealEstateLoanTypeAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "stringItemType" }, "srt_MortgageLoansOnRealEstateLoanTypeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Type of loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.", "label": "Mortgage Loans On Real Estate Loan Type [Domain]", "terseLabel": "Mortgage Loans on Real Estate, Loan Type [Domain]" } } }, "localname": "MortgageLoansOnRealEstateLoanTypeDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "srt_MortgageLoansOnRealEstateNamePropertyTypeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Land and any structures permanently fixed to it.", "label": "Mortgage Loans On Real Estate Name Property Type [Domain]", "terseLabel": "Real Estate [Domain]" } } }, "localname": "MortgageLoansOnRealEstateNamePropertyTypeDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_OfficeBuildingMember": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Building designed primarily for the conduct of business, for example, but not limited to, administration, clerical services, and consultation.", "label": "Office Building [Member]", "terseLabel": "Office" } } }, "localname": "OfficeBuildingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_OtherPropertyMember": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Property classified as other.", "label": "Other Property [Member]", "terseLabel": "Mixed use/other" } } }, "localname": "OtherPropertyMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_ParentCompanyMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The registrant that controls, directly or indirectly, another entity (or entities). The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree.", "label": "Parent Company [Member]", "terseLabel": "Principal Financial Group, Inc. parent only" } } }, "localname": "ParentCompanyMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "srt_ProductOrServiceAxis": { "auth_ref": [ "r190", "r361", "r362", "r767", "r774" ], "lang": { "en-US": { "role": { "documentation": "Information by product and service, or group of similar products and similar services.", "label": "Products and Services [Axis]" } } }, "localname": "ProductOrServiceAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "stringItemType" }, "srt_ProductsAndServicesDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Product or service, or a group of similar products or similar services.", "label": "Products And Services [Domain]", "terseLabel": "Products and Services [Domain]" } } }, "localname": "ProductsAndServicesDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "domainItemType" }, "srt_RangeAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by statistical measurement. Includes, but is not limited to, minimum, maximum, weighted average, arithmetic average, and median.", "label": "Range [Axis]" } } }, "localname": "RangeAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "stringItemType" }, "srt_RangeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Statistical measurement. Includes, but is not limited to, minimum, maximum, weighted average, arithmetic average, and median.", "label": "Range [Member]", "terseLabel": "Range [Domain]" } } }, "localname": "RangeMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "domainItemType" }, "srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]", "terseLabel": "Reinsurance information" } } }, "localname": "ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "stringItemType" }, "srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable": { "auth_ref": [ "r745", "r858" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of supplemental information about reinsurance including, but not limited to, type of insurance, gross amount of premium, premium ceded to another company, premium assumed from another company, net amount of premium revenue, and percentage of premium assumed to net premium revenue.", "label": "Reinsurance [Table]" } } }, "localname": "ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "stringItemType" }, "srt_ReportableLegalEntitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Legal entities of the consolidated entity reporting separate financial information in the entity's financial statements.", "label": "Reportable Legal Entities [Member]", "terseLabel": "Legal Entities" } } }, "localname": "ReportableLegalEntitiesMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "domainItemType" }, "srt_RepurchaseAgreementCounterpartyNameDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Named other party that participates in a financial transaction. Examples include, but not limited to, the name of the financial institution.", "label": "Repurchase Agreement Counterparty Name [Domain]", "terseLabel": "Counterparty Name [Domain]" } } }, "localname": "RepurchaseAgreementCounterpartyNameDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "domainItemType" }, "srt_RestatementAdjustmentMember": { "auth_ref": [ "r147", "r149", "r150", "r151" ], "lang": { "en-US": { "role": { "documentation": "Effect of a correction of an error, other prior year adjustment, or application of a new accounting pronouncement on a financial statement line item or any per share amounts. The cumulative effect of the change on retained earnings or net assets in the statement of financial position would also be represented under this domain member.", "label": "Restatement Adjustment [Member]", "terseLabel": "Adjustment for adoption of guidance" } } }, "localname": "RestatementAdjustmentMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "domainItemType" }, "srt_RestatementAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by revision of previously issued financial statements.", "label": "Restatement [Axis]" } } }, "localname": "RestatementAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "stringItemType" }, "srt_RestatementDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Revision of previously issued financial statements.", "label": "Restatement [Domain]", "terseLabel": "Restatement [Domain]" } } }, "localname": "RestatementDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "domainItemType" }, "srt_RetailSiteMember": { "auth_ref": [ "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Locations where products are offered for sale to consumers.", "label": "Retail Site [Member]", "terseLabel": "Retail" } } }, "localname": "RetailSiteMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "domainItemType" }, "srt_ScheduleOfCondensedFinancialStatementsTable": { "auth_ref": [ "r142", "r510", "r855", "r864", "r865", "r866" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about condensed financial statements, including, but not limited to, the balance sheet, income statement, and statement of cash flows.", "label": "Schedule of Condensed Financial Statements [Table]" } } }, "localname": "ScheduleOfCondensedFinancialStatementsTable", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "srt_SegmentGeographicalDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Geographical area.", "label": "Segment Geographical [Domain]", "terseLabel": "Geographical [Domain]" } } }, "localname": "SegmentGeographicalDomain", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsAAARatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "AAA credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors A A A Rating [Member]", "terseLabel": "AAA" } } }, "localname": "StandardPoorsAAARatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsAARatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "AA credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors A A Rating [Member]", "terseLabel": "AA" } } }, "localname": "StandardPoorsAARatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsARatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors A Rating [Member]", "terseLabel": "A" } } }, "localname": "StandardPoorsARatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsBBBRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "BBB credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors B B B Rating [Member]", "terseLabel": "BBB" } } }, "localname": "StandardPoorsBBBRatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsBBRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "BB credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors B B Rating [Member]", "terseLabel": "BB" } } }, "localname": "StandardPoorsBBRatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StandardPoorsCCCRatingMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "CCC credit rating as defined by the external credit rating agency, Standard & Poor's.", "label": "Standard Poors C C C Rating [Member]", "terseLabel": "CCC" } } }, "localname": "StandardPoorsCCCRatingMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "srt_StatementGeographicalAxis": { "auth_ref": [ "r191", "r361", "r363", "r775", "r835", "r837", "r846", "r849" ], "lang": { "en-US": { "role": { "documentation": "Information by geographical components.", "label": "Geographical [Axis]" } } }, "localname": "StatementGeographicalAxis", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "stringItemType" }, "srt_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Schedule I - Summary of Investments - Other Than Investments in Related Parties" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesAbstract", "nsuri": "http://fasb.org/srt/2019-01-31", "xbrltype": "stringItemType" }, "srt_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesReportableDataLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]", "terseLabel": "Summary of Investments - Other Than Investments in Related Parties" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesReportableDataLineItems", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "stringItemType" }, "srt_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTable": { "auth_ref": [ "r833", "r856" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about investment held by insurance company, excluding investment in related party.", "label": "Summary of Investments, Other than Investments in Related Parties [Table]" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTable", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "stringItemType" }, "srt_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock": { "auth_ref": [ "r833", "r856" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure of information about investment held by insurance company, excluding investment in related party.", "label": "Summary of Investments, Other than Investments in Related Parties [Text Block]", "terseLabel": "Schedule I - Summary of Investments - Other Than Investments in Related Parties" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedParties" ], "xbrltype": "textBlockItemType" }, "srt_SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Schedule IV - Reinsurance" } } }, "localname": "SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesAbstract", "nsuri": "http://fasb.org/srt/2019-01-31", "xbrltype": "stringItemType" }, "srt_SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock": { "auth_ref": [ "r745", "r858" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for the supplemental schedule of reinsurance information. Reinsurance schedule includes, but is not limited to, the type of insurance, gross amount of premiums, premiums ceded to other entities, premiums assumed from other entities, net amount of premium revenue, and the percentage of the premiums assumed to net premium revenue.", "label": "Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Text Block]", "terseLabel": "Schedule IV - Reinsurance" } } }, "localname": "SupplementalScheduleOfReinsurancePremiumsForInsuranceCompaniesTextBlock", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsurance" ], "xbrltype": "textBlockItemType" }, "srt_SupplementaryInsuranceInformationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Schedule III - Supplementary Insurance Information" } } }, "localname": "SupplementaryInsuranceInformationAbstract", "nsuri": "http://fasb.org/srt/2019-01-31", "xbrltype": "stringItemType" }, "srt_SupplementaryInsuranceInformationBySegmentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Supplementary Insurance Information, by Segment [Line Items]", "terseLabel": "Supplementary Insurance Information" } } }, "localname": "SupplementaryInsuranceInformationBySegmentLineItems", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails" ], "xbrltype": "stringItemType" }, "srt_SupplementaryInsuranceInformationBySegmentTable": { "auth_ref": [ "r739", "r857" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about supplementary insurance information by segment. Includes, but is not limited to, deferred policy acquisition cost; future policy benefit, loss, claim and loss expenses; unearned premium; other policy claim and benefit payable; premium revenue; net investment income; benefit, claim, loss and settlement expenses; amortization of deferred policy acquisition cost; other operating expense; and premium written.", "label": "Supplementary Insurance Information, by Segment [Table]" } } }, "localname": "SupplementaryInsuranceInformationBySegmentTable", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails" ], "xbrltype": "stringItemType" }, "srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock": { "auth_ref": [ "r739", "r857" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for supplementary insurance information by segment. Includes, but is not limited to, deferred policy acquisition cost; future policy benefit, loss, claim and loss expenses; unearned premium; other policy claim and benefit payable; premium revenue; net investment income; benefit, claim, loss and settlement expenses; amortization of deferred policy acquisition cost; other operating expense; and premium written.", "label": "Supplementary Insurance Information, for Insurance Companies Disclosure [Text Block]", "terseLabel": "Schedule III - Supplementary Insurance Information" } } }, "localname": "SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformation" ], "xbrltype": "textBlockItemType" }, "srt_WeightedAverageMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Average of a range of values, calculated with consideration of proportional relevance.", "label": "Weighted Average [Member]", "terseLabel": "Weighted average input" } } }, "localname": "WeightedAverageMember", "nsuri": "http://fasb.org/srt/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AOCIAttributableToParentNetOfTaxRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "AOCI Attributable to Parent, Net of Tax [Roll Forward]", "terseLabel": "Change in accumulated other comprehensive income (loss) rollforward" } } }, "localname": "AOCIAttributableToParentNetOfTaxRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AccidentAndHealthInsuranceSegmentMember": { "auth_ref": [ "r746", "r776" ], "lang": { "en-US": { "role": { "documentation": "Product line consisting of insurance against loss by illness or injury, including but not limited to medical, dental, disability, workmen's compensation and long-term care.", "label": "Accident And Health Insurance Segment [Member]", "terseLabel": "Accident and health insurance" } } }, "localname": "AccidentAndHealthInsuranceSegmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccountingStandardsUpdate201409Member": { "auth_ref": [ "r364" ], "lang": { "en-US": { "role": { "documentation": "Accounting Standards Update 2014-09 Revenue from Contracts with Customers (Topic 606).", "label": "Accounting Standards Update201409 [Member]", "terseLabel": "ASU 2014-09 - Revenue recognition" } } }, "localname": "AccountingStandardsUpdate201409Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccountingStandardsUpdate201601Member": { "auth_ref": [ "r614" ], "lang": { "en-US": { "role": { "documentation": "Accounting Standards Update 2016-01 Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.", "label": "Accounting Standards Update201601 [Member]", "terseLabel": "ASU 2016-01 - Equity investments" } } }, "localname": "AccountingStandardsUpdate201601Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccountingStandardsUpdate201602Member": { "auth_ref": [ "r631" ], "lang": { "en-US": { "role": { "documentation": "Accounting Standards Update 2016-02 Leases (Topic 842).", "label": "Accounting Standards Update201602 [Member]", "terseLabel": "ASU 2016-02 - Leases" } } }, "localname": "AccountingStandardsUpdate201602Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccountingStandardsUpdate201616Member": { "auth_ref": [ "r493", "r494" ], "lang": { "en-US": { "role": { "documentation": "Accounting Standards Update 2016-16 Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.", "label": "Accounting Standards Update201616 [Member]", "terseLabel": "ASU 2016-16 - Intra-entity asset transfer taxes" } } }, "localname": "AccountingStandardsUpdate201616Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccountingStandardsUpdate201802Member": { "auth_ref": [ "r81" ], "lang": { "en-US": { "role": { "documentation": "Accounting Standards Update 2018-02 Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.", "label": "Accounting Standards Update201802 [Member]", "terseLabel": "ASU 2018-02 - Reclassification of certain tax effects" } } }, "localname": "AccountingStandardsUpdate201802Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccountsNotesAndLoansReceivableLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Accounts, Notes, Loans and Financing Receivable [Line Items]", "terseLabel": "Mortgage loan disclosures" } } }, "localname": "AccountsNotesAndLoansReceivableLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AccruedIncomeTaxes": { "auth_ref": [ "r19", "r21", "r470", "r660", "r701" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 6.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all domestic and foreign income tax obligations due. This amount is the total of current and noncurrent accrued income taxes.", "label": "Accrued Income Taxes", "terseLabel": "Income taxes currently payable" } } }, "localname": "AccruedIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_AccruedInvestmentIncomeReceivable": { "auth_ref": [ "r27", "r657", "r710" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 10.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 3.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.", "label": "Accrued Investment Income Receivable", "terseLabel": "Accrued investment income" } } }, "localname": "AccruedInvestmentIncomeReceivable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember": { "auth_ref": [ "r62", "r69", "r72", "r397", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive (income) loss related to defined benefit plans including the portion attributable to the noncontrolling interest.", "label": "Accumulated Defined Benefit Plans Adjustment Including Portion Attributable To Noncontrolling Interest [Member]", "terseLabel": "Unrecognized postretirement benefit obligation including NCI" } } }, "localname": "AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember": { "auth_ref": [ "r62", "r69", "r72", "r397", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive (income) loss related to defined benefit plans attributable to the parent.", "label": "Accumulated Defined Benefit Plans Adjustment [Member]", "terseLabel": "Unrecognized postretirement benefit obligation" } } }, "localname": "AccumulatedDefinedBenefitPlansAdjustmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember": { "auth_ref": [ "r55", "r69", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) resulting from foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to the noncontrolling interest.", "label": "Accumulated Foreign Currency Adjustment Attributable To Noncontrolling Interest [Member]", "terseLabel": "Foreign currency translation adjustment relating to noncontrolling interest" } } }, "localname": "AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember": { "auth_ref": [ "r55", "r69", "r72", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) resulting from foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, including the portion attributable to the noncontrolling interest.", "label": "Accumulated Foreign Currency Adjustment Including Portion Attributable To Noncontrolling Interest [Member]", "terseLabel": "Foreign currency translation adjustment including NCI" } } }, "localname": "AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember": { "auth_ref": [ "r69", "r522" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) from gain (loss) of derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, including portion attributable to noncontrolling interest.", "label": "Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest [Member]", "terseLabel": "Net unrealized gains (losses) on derivative instruments including NCI" } } }, "localname": "AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember": { "auth_ref": [ "r56", "r69", "r72", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) resulting from gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges, including the portion attributable to the noncontrolling interest.", "label": "Accumulated Net Gain Loss From Cash Flow Hedges Including Portion Attributable To Noncontrolling Interest [Member]", "terseLabel": "Net unrealized gains (losses) on derivative instruments including NCI" } } }, "localname": "AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember": { "auth_ref": [ "r56", "r69", "r72", "r522" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) resulting from gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges, attributable to the parent.", "label": "Accumulated Net Gain Loss From Designated Or Qualifying Cash Flow Hedges [Member]", "terseLabel": "Net unrealized gains (losses) on derivative instruments" } } }, "localname": "AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedNetInvestmentGainLossIncludingPortionAttributableToNoncontrollingInterestMember": { "auth_ref": [ "r57", "r58", "r60", "r69", "r72" ], "lang": { "en-US": { "role": { "documentation": "Accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), including portion attributable to noncontrolling interest.", "label": "Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest [Member]", "terseLabel": "Net unrealized gains (losses) on available-for-sale securities including NCI" } } }, "localname": "AccumulatedNetInvestmentGainLossIncludingPortionAttributableToNoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember": { "auth_ref": [ "r57", "r58", "r60", "r69", "r72" ], "lang": { "en-US": { "role": { "documentation": "Accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), attributable to parent.", "label": "Accumulated Net Unrealized Investment Gain Loss [Member]", "terseLabel": "Net unrealized gains (losses) on available-for-sale securities" } } }, "localname": "AccumulatedNetUnrealizedInvestmentGainLossMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Accumulated Other Comprehensive Income (Loss) [Line Items]", "terseLabel": "Change in Accumulated Other Comprehensive Income (Loss)" } } }, "localname": "AccumulatedOtherComprehensiveIncomeLossLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax": { "auth_ref": [ "r66", "r68", "r69" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 4.0, "parentTag": "us-gaap_StockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.", "label": "Accumulated Other Comprehensive Income (Loss), Net of Tax", "terseLabel": "Accumulated other comprehensive income (loss)", "verboseLabel": "Accumulated other comprehensive income (loss)" } } }, "localname": "AccumulatedOtherComprehensiveIncomeLossNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_AccumulatedOtherComprehensiveIncomeLossTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about components of accumulated other comprehensive income (loss).", "label": "Accumulated Other Comprehensive Income (Loss) [Table]" } } }, "localname": "AccumulatedOtherComprehensiveIncomeLossTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AccumulatedOtherComprehensiveIncomeMember": { "auth_ref": [ "r65", "r69", "r72", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated increase (decrease) in equity from transactions and other events and circumstances from non-owner sources, attributable to the parent. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners.", "label": "Accumulated Other Comprehensive Income [Member]", "terseLabel": "Accumulated other comprehensive income (loss)" } } }, "localname": "AccumulatedOtherComprehensiveIncomeMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AccumulatedTranslationAdjustmentMember": { "auth_ref": [ "r55", "r69", "r72", "r523" ], "lang": { "en-US": { "role": { "documentation": "Accumulated other comprehensive income (loss) resulting from foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to the parent.", "label": "Accumulated Translation Adjustment [Member]", "terseLabel": "Foreign currency translation adjustment" } } }, "localname": "AccumulatedTranslationAdjustmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AdditionalCollateralAggregateFairValue": { "auth_ref": [ "r567" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.", "label": "Additional Collateral, Aggregate Fair Value", "terseLabel": "Additional collateral required to be posted if derivative credit-risk-related contingent features were triggered" } } }, "localname": "AdditionalCollateralAggregateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AdditionalPaidInCapital": { "auth_ref": [ "r28" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_StockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.", "label": "Additional Paid in Capital", "terseLabel": "Additional paid-in capital" } } }, "localname": "AdditionalPaidInCapital", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_AdditionalPaidInCapitalMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders.", "label": "Additional Paid In Capital [Member]", "terseLabel": "Additional paid-in capital" } } }, "localname": "AdditionalPaidInCapitalMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_AdditionsToContractHoldersFunds": { "auth_ref": [ "r105" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 12.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow from a segregated fund account during the period.", "label": "Additions to Contract Holders Funds", "terseLabel": "Investment contract deposits" } } }, "localname": "AdditionsToContractHoldersFunds", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_AdjustmentsForNewAccountingPronouncementsAxis": { "auth_ref": [ "r146" ], "lang": { "en-US": { "role": { "documentation": "Information by new accounting pronouncement.", "label": "Adjustments for New Accounting Pronouncements [Axis]" } } }, "localname": "AdjustmentsForNewAccountingPronouncementsAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "stringItemType" }, "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities": { "auth_ref": [ "r119" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 2.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The sum of adjustments which are added to or deducted from net income or loss, including the portion attributable to noncontrolling interest, to reflect cash provided by or used in operating activities, in accordance with the indirect cash flow method.", "label": "Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities", "totalLabel": "Net adjustments" } } }, "localname": "AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]", "terseLabel": "Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:", "verboseLabel": "Adjustments to reconcile net income to net cash provided by operating activities:" } } }, "localname": "AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_AdministrativeServiceMember": { "auth_ref": [ "r362" ], "lang": { "en-US": { "role": { "documentation": "Administrative assistance, including, but not limited to, accounting, tax, legal, regulatory filing, and share registration of managed fund and investment account of independent third party, and related and affiliated entity.", "label": "Administrative Service [Member]", "terseLabel": "Administrative service fee revenue" } } }, "localname": "AdministrativeServiceMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AllOtherCorporateBondsMember": { "auth_ref": [ "r222" ], "lang": { "en-US": { "role": { "documentation": "Investments in corporate fixed maturity debt securities classified as other.", "label": "All Other Corporate Bonds [Member]", "terseLabel": "All other corporate bonds" } } }, "localname": "AllOtherCorporateBondsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock": { "auth_ref": [ "r202", "r260" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of allowance for credit loss on financing receivable.", "label": "Allowance for Credit Losses on Financing Receivables [Table Text Block]", "terseLabel": "Mortgage Loan Valuation Allowance (Table)" } } }, "localname": "AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_AmortizationOfIntangibleAssets": { "auth_ref": [ "r118", "r293", "r301" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.", "label": "Amortization of Intangible Assets", "terseLabel": "Amortization expense for intangible assets with finite useful lives" } } }, "localname": "AmortizationOfIntangibleAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax": { "auth_ref": [ "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount recognized in net periodic benefit cost (credit) and other comprehensive (income) loss.", "label": "Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax", "totalLabel": "Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss" } } }, "localname": "AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax": { "auth_ref": [ "r66" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after tax, of accumulated gain (loss) on derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.", "label": "AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax", "terseLabel": "Net gains (losses) reported in AOCI related to active cash flow hedges of forecasted transactions" } } }, "localname": "AociLossCashFlowHedgeCumulativeGainLossAfterTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_Assets": { "auth_ref": [ "r181", "r658", "r696" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.", "label": "Assets", "terseLabel": "Total assets", "totalLabel": "Total assets" } } }, "localname": "Assets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Assets [Abstract]", "terseLabel": "Assets" } } }, "localname": "AssetsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "stringItemType" }, "us-gaap_AssetsDesignatedToClosedBlock": { "auth_ref": [ "r807", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 1.0, "parentTag": "us-gaap_ExcessOfReportedClosedBlockLiabilitiesOverAssetsDesignatedToClosedBlock", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The sum of cash, cash equivalents, investments and other assets allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Assets Designated to Closed Block", "totalLabel": "Total assets designated to the Closed Block" } } }, "localname": "AssetsDesignatedToClosedBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Assets Designated to Closed Block [Abstract]", "terseLabel": "Assets designated to the Closed Block" } } }, "localname": "AssetsDesignatedToClosedBlockAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AssetsDesignatedToClosedBlockAccruedInvestmentIncome": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 3.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of accrued investment income held by the closed block.", "label": "Assets Designated to Closed Block, Accrued Investment Income", "terseLabel": "Closed Block assets: Accrued investment income" } } }, "localname": "AssetsDesignatedToClosedBlockAccruedInvestmentIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockCashAndCashEquivalents": { "auth_ref": [ "r807", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 2.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Cash and highly liquid, safe investments that can be readily converted into cash (cash equivalents) allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Assets Designated to Closed Block, Cash and Cash Equivalents", "terseLabel": "Closed Block assets: Cash and cash equivalents" } } }, "localname": "AssetsDesignatedToClosedBlockCashAndCashEquivalents", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockDeferredTaxAssetNet": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 5.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after valuation allowance and deferred tax liability, of deferred tax asset pertaining to the closed block.", "label": "Assets Designated to Closed Block, Deferred Tax Asset, Net", "terseLabel": "Closed Block assets: Deferred tax asset" } } }, "localname": "AssetsDesignatedToClosedBlockDeferredTaxAssetNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockEquitySecuritiesAtFairValue": { "auth_ref": [ "r807", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 3.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of equity securities allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Assets Designated to Closed Block, Equity Securities, at Fair Value", "terseLabel": "Closed Block assets: Equity securities" } } }, "localname": "AssetsDesignatedToClosedBlockEquitySecuritiesAtFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockFixedMaturityAvailableForSaleAtFairValue": { "auth_ref": [ "r807", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 1.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investments in debt securities that are deemed to be available for sale that are allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block. Change in fair of such securities is a component of change in other comprehensive income in the period, which is reflected in the closed block disclosure.", "label": "Assets Designated to Closed Block, Fixed Maturity, Available-for-sale, at Fair Value", "terseLabel": "Closed Block assets: Fixed maturities, available-for-sale" } } }, "localname": "AssetsDesignatedToClosedBlockFixedMaturityAvailableForSaleAtFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockInvestments": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 1.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investments held by the closed block.", "label": "Assets Designated to Closed Block, Investments", "totalLabel": "Closed Block assets: Total investments" } } }, "localname": "AssetsDesignatedToClosedBlockInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockMortgageLoansOnRealEstate": { "auth_ref": [ "r807", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 4.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount of investments in mortgage loans on real estate allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Assets Designated to Closed Block, Mortgage Loans on Real Estate", "terseLabel": "Closed Block assets: Mortgage loans" } } }, "localname": "AssetsDesignatedToClosedBlockMortgageLoansOnRealEstate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockOtherInvestments": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 6.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of other investments held by the closed block.", "label": "Assets Designated to Closed Block, Other Investments", "terseLabel": "Closed Block assets: Other investments" } } }, "localname": "AssetsDesignatedToClosedBlockOtherInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockPolicyLoans": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 5.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount of loans to policy holders secured by benefits under insurance policies that are allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Assets Designated to Closed Block, Policy Loans", "terseLabel": "Closed Block assets: Policy loans" } } }, "localname": "AssetsDesignatedToClosedBlockPolicyLoans", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockPremiumsAndOtherReceivablesNet": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 4.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after the allowance for doubtful accounts, of premium and other receivables held by the closed block.", "label": "Assets Designated to Closed Block, Premiums and Other Receivables, Net", "terseLabel": "Closed Block assets: Premiums due and other receivables" } } }, "localname": "AssetsDesignatedToClosedBlockPremiumsAndOtherReceivablesNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsDesignatedToClosedBlockTradingSecuritiesDebt": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 2.0, "parentTag": "us-gaap_AssetsDesignatedToClosedBlockInvestments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investments in debt securities classified as trading that are held by the closed block.", "label": "Assets Designated to Closed Block, Trading Securities, Debt", "terseLabel": "Closed Block assets: Fixed maturities, trading" } } }, "localname": "AssetsDesignatedToClosedBlockTradingSecuritiesDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssetsFairValueDisclosure": { "auth_ref": [ "r586" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 1.0, "parentTag": "us-gaap_FairValueNetAssetLiability", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.", "label": "Assets, Fair Value Disclosure", "totalLabel": "Total assets", "verboseLabel": "Assets measured at fair value" } } }, "localname": "AssetsFairValueDisclosure", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AssumedPremiumsEarned": { "auth_ref": [ "r726", "r742", "r791", "r794" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 2.0, "parentTag": "us-gaap_PremiumsEarnedNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of earned premiums assumed from other entities.", "label": "Assumed Premiums Earned", "terseLabel": "Premiums assumed from other companies", "verboseLabel": "Premiums and other considerations, Assumed" } } }, "localname": "AssumedPremiumsEarned", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax": { "auth_ref": [ "r225" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails": { "order": 1.0, "parentTag": "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax", "terseLabel": "Gross unrealized gains, fixed maturities" } } }, "localname": "AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax": { "auth_ref": [ "r226" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails": { "order": 2.0, "parentTag": "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax", "terseLabel": "Gross unrealized losses, fixed maturities" } } }, "localname": "AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis": { "auth_ref": [ "r223", "r270" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Available-for-sale Debt Securities, Amortized Cost Basis", "totalLabel": "Amortized cost, fixed maturities" } } }, "localname": "AvailableForSaleDebtSecuritiesAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]", "terseLabel": "Gross Unrealized Losses for Fixed Maturities" } } }, "localname": "AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]", "terseLabel": "Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure" } } }, "localname": "AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]", "terseLabel": "Amortized cost of fixed maturities available-for-sale" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]", "terseLabel": "Fair value of fixed maturities available-for-sale" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "stringItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 1.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis", "terseLabel": "Due in one year or less" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 1.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value", "terseLabel": "Due in one year or less" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 4.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis", "terseLabel": "Due after ten years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 4.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value", "terseLabel": "Due after ten years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 3.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in rolling sixth through tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis", "terseLabel": "Due after five years through ten years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 3.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in rolling sixth through tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value", "terseLabel": "Due after five years through ten years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 2.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year through fifth year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis", "terseLabel": "Due after one year through five years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 2.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year through fifth year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.", "label": "Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value", "terseLabel": "Due after one year through five years" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate": { "auth_ref": [ "r227", "r228", "r681" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 1.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtSecurities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date.", "label": "Available-for-sale Securities, Debt Maturities, Single Maturity Date", "totalLabel": "Subtotal" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis": { "auth_ref": [ "r227", "r228", "r681" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 1.0, "parentTag": "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date.", "label": "Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis", "totalLabel": "Subtotal" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost": { "auth_ref": [ "r228" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 2.0, "parentTag": "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.", "label": "Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis", "terseLabel": "Mortgage-backed and other asset-backed securities" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue": { "auth_ref": [ "r228" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": 2.0, "parentTag": "us-gaap_AvailableForSaleSecuritiesDebtSecurities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.", "label": "Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value", "terseLabel": "Mortgage-backed and other asset-backed securities" } } }, "localname": "AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableForSaleSecuritiesDebtSecurities": { "auth_ref": [ "r217", "r224", "r270" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 1.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 1.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 }, "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails": { "order": 3.0, "parentTag": "us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 1.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Available-for-sale Securities, Debt Securities", "positiveLabel": "Fair value, fixed maturities", "terseLabel": "Fixed maturities, available-for-sale", "totalLabel": "Fair value, fixed maturities", "verboseLabel": "Fixed maturities, available-for-sale (2019 and 2018 include $99.4 million and $94.5 million related to consolidated variable interest entities)" } } }, "localname": "AvailableForSaleSecuritiesDebtSecurities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureInvestmentsAmortizationByExpectedMaturityDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_AvailableforsaleSecuritiesMember": { "auth_ref": [ "r239" ], "lang": { "en-US": { "role": { "documentation": "Investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Availableforsale Securities [Member]", "terseLabel": "Available-for-sale" } } }, "localname": "AvailableforsaleSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_AwardTypeAxis": { "auth_ref": [ "r423", "r452" ], "lang": { "en-US": { "role": { "documentation": "Information by type of award under share-based payment arrangement.", "label": "Award Type [Axis]" } } }, "localname": "AwardTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_BalanceSheetLocationAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by location on balance sheet (statement of financial position).", "label": "Balance Sheet Location [Axis]" } } }, "localname": "BalanceSheetLocationAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_BalanceSheetLocationDomain": { "auth_ref": [ "r544", "r548" ], "lang": { "en-US": { "role": { "documentation": "Location in the balance sheet (statement of financial position).", "label": "Balance Sheet Location [Domain]", "terseLabel": "Balance Sheet Location [Domain]" } } }, "localname": "BalanceSheetLocationDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_BanksTrustAndInsuranceEquitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents investments by the reporting entity in equity securities issued by a bank, a trust or an insurance company.", "label": "Banks Trust And Insurance Equities [Member]", "terseLabel": "Common stocks: Banks, trust and insurance companies" } } }, "localname": "BanksTrustAndInsuranceEquitiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_BasisOfAccountingPolicyPolicyTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS).", "label": "Basis of Accounting, Policy [Policy Text Block]", "terseLabel": "Basis of Presentation - Policy" } } }, "localname": "BasisOfAccountingPolicyPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_BenefitsLossesAndExpenses": { "auth_ref": [ "r737" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The total amount of expense recognized during the period for future policy benefits, claims and claims adjustment costs, and for selling, general and administrative costs.", "label": "Benefits, Losses and Expenses", "terseLabel": "Total expenses", "totalLabel": "Total expenses" } } }, "localname": "BenefitsLossesAndExpenses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_BenefitsLossesAndExpensesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Benefits, Losses and Expenses [Abstract]", "terseLabel": "Expenses" } } }, "localname": "BenefitsLossesAndExpensesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "stringItemType" }, "us-gaap_BusinessAcquisitionAcquireeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Identification of the acquiree in a material business combination (or series of individually immaterial business combinations), which may include the name or other type of identification of the acquiree.", "label": "Business Acquisition Acquiree [Domain]", "terseLabel": "Business Acquisition, Acquiree [Domain]" } } }, "localname": "BusinessAcquisitionAcquireeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails", "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_BusinessAcquisitionAxis": { "auth_ref": [ "r504", "r505" ], "lang": { "en-US": { "role": { "documentation": "Information by business combination or series of individually immaterial business combinations.", "label": "Business Acquisition [Axis]" } } }, "localname": "BusinessAcquisitionAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails", "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_BusinessAcquisitionLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Business Acquisition [Line Items]", "verboseLabel": "Goodwill and Other Intangible Assets" } } }, "localname": "BusinessAcquisitionLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "stringItemType" }, "us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh": { "auth_ref": [ "r509" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.", "label": "Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High", "terseLabel": "Maximum additional earn-out payment based upon retention of fee revenue" } } }, "localname": "BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet": { "auth_ref": [ "r626" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The total gross amount less the charge for the use of the long-lived depreciable assets subject to a lease meeting the criteria for capitalization.", "label": "Capital Leases, Balance Sheet, Assets by Major Class, Net", "terseLabel": "Capital lease assets" } } }, "localname": "CapitalLeasesBalanceSheetAssetsByMajorClassNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalLeasesIncomeStatementAmortizationExpense": { "auth_ref": [ "r625", "r839" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The charge for the use of long-lived depreciable capital leased assets for the period.", "label": "Capital Leases, Income Statement, Amortization Expense", "terseLabel": "Capital lease depreciation expense" } } }, "localname": "CapitalLeasesIncomeStatementAmortizationExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalLeasesNetInvestmentInDirectFinancingLeases": { "auth_ref": [ "r627" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The net investment in direct financing leases as of the balance sheet date consisting of: (a) minimum lease payments due on direct financing leases, (b) unguaranteed residual value, and (c) any unamortized initial direct costs; less: (i) executory costs, (ii) unearned income, and (iii) the accumulated allowance for uncollectible minimum lease payments.", "label": "Capital Leases, Net Investment in Direct Financing Leases", "terseLabel": "Direct financing leases" } } }, "localname": "CapitalLeasesNetInvestmentInDirectFinancingLeases", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalizationOfDeferredPolicyAcquisitionCostsPolicy": { "auth_ref": [ "r128", "r748" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for deferred policy acquisition costs, including the nature, type, and amount of capitalized costs incurred to write or acquire insurance contracts, and the basis for and methodologies applied in capitalizing and amortizing such costs.", "label": "Deferred Policy Acquisition Costs, Policy [Policy Text Block]", "terseLabel": "Deferred Acquisition Costs - Policy" } } }, "localname": "CapitalizationOfDeferredPolicyAcquisitionCostsPolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_CapitalizedContractCostAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Capitalized Contract Cost [Abstract]", "terseLabel": "Contract costs" } } }, "localname": "CapitalizedContractCostAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CapitalizedContractCostAmortization": { "auth_ref": [ "r282" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer.", "label": "Capitalized Contract Cost, Amortization", "terseLabel": "Amortization expense of contract cost asset" } } }, "localname": "CapitalizedContractCostAmortization", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalizedContractCostImpairmentLoss": { "auth_ref": [ "r282" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer.", "label": "Capitalized Contract Cost, Impairment Loss", "terseLabel": "Impairment loss for contract cost asset" } } }, "localname": "CapitalizedContractCostImpairmentLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CapitalizedContractCostNet": { "auth_ref": [ "r281" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.", "label": "Capitalized Contract Cost, Net", "terseLabel": "Contract cost asset" } } }, "localname": "CapitalizedContractCostNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CarryingReportedAmountFairValueDisclosureMember": { "auth_ref": [ "r606", "r607" ], "lang": { "en-US": { "role": { "documentation": "Measured as reported on the statement of financial position (balance sheet).", "label": "Carrying Reported Amount Fair Value Disclosure [Member]", "terseLabel": "Carrying amount" } } }, "localname": "CarryingReportedAmountFairValueDisclosureMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CashAndCashEquivalentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Cash and Cash Equivalents [Abstract]", "terseLabel": "Cash and Cash Equivalents" } } }, "localname": "CashAndCashEquivalentsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesCashAndCashEquivalentsInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CashAndCashEquivalentsAtCarryingValue": { "auth_ref": [ "r8", "r34", "r120" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 9.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 3.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.", "label": "Cash and Cash Equivalents, at Carrying Value", "terseLabel": "Cash and cash equivalents" } } }, "localname": "CashAndCashEquivalentsAtCarryingValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_CashAndCashEquivalentsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.", "label": "Cash And Cash Equivalents [Member]", "terseLabel": "Cash and cash equivalents" } } }, "localname": "CashAndCashEquivalentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CashAndCashEquivalentsPolicyTextBlock": { "auth_ref": [ "r11", "r122", "r128" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.", "label": "Cash and Cash Equivalents, Policy [Policy Text Block]", "terseLabel": "Cash and Cash Equivalents - Policy" } } }, "localname": "CashAndCashEquivalentsPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents": { "auth_ref": [ "r113", "r120", "r127" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.", "label": "Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents", "periodEndLabel": "Cash and cash equivalents at end of period", "periodStartLabel": "Cash and cash equivalents at beginning of period" } } }, "localname": "CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect": { "auth_ref": [ "r113", "r616" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.", "label": "Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect", "totalLabel": "Net increase (decrease) in cash and cash equivalents" } } }, "localname": "CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths": { "auth_ref": [ "r581" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.", "label": "Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months", "terseLabel": "Net gains (losses) expected to be reclassified from accumulated OCI into net income in the next 12 months" } } }, "localname": "CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CashFlowHedgingMember": { "auth_ref": [ "r540" ], "lang": { "en-US": { "role": { "documentation": "Hedge of the exposure to variability in the cash flows of a recognized asset or liability, or of a forecasted transaction, that is attributable to a particular risk.", "label": "Cash Flow Hedging [Member]", "terseLabel": "Cash Flow Hedges" } } }, "localname": "CashFlowHedgingMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]", "terseLabel": "Supplemental disclosure of non-cash activities:" } } }, "localname": "CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_CashSurrenderValueOfLifeInsurance": { "auth_ref": [ "r9", "r36" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.", "label": "Cash Surrender Value of Life Insurance", "terseLabel": "Cash surrender value of company owned life insurance" } } }, "localname": "CashSurrenderValueOfLifeInsurance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CededPremiumsEarned": { "auth_ref": [ "r726", "r741", "r788", "r789", "r792", "r794" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 3.0, "parentTag": "us-gaap_PremiumsEarnedNet", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of earned premiums ceded to other entities.", "label": "Ceded Premiums Earned", "negatedLabel": "Premiums and other considerations, Ceded", "terseLabel": "Premiums ceded to other companies" } } }, "localname": "CededPremiumsEarned", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1": { "auth_ref": [ "r578" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.", "label": "Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments", "terseLabel": "Gain (loss) recognized on derivatives" } } }, "localname": "ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1": { "auth_ref": [ "r578" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.", "label": "Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge", "terseLabel": "Gain (loss) recognized on hedged item" } } }, "localname": "ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClaimsDevelopmentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Claims Development [Line Items]", "terseLabel": "Claims Development" } } }, "localname": "ClaimsDevelopmentLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClassOfStockLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Class of Stock [Line Items]" } } }, "localname": "ClassOfStockLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockAccountingPolicy": { "auth_ref": [ "r787", "r804" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for defined, limited group of policies and defined set of assets governed by set of operating rules to preserve reasonable dividend expectation of individual policyholder with individual life, health, and annuity policies for which dividends are currently being paid or are expected to be paid under current dividend scale.", "label": "Closed Block Accounting Policy [Policy Text Block]", "verboseLabel": "Closed Block" } } }, "localname": "ClosedBlockAccountingPolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_ClosedBlockAssetsAndLiabilitiesEffectOnOtherComprehensiveIncome": { "auth_ref": [ "r808", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The increase or decrease in the period in other comprehensive income within the closed block comprised of the change in (a) dividend obligation to policyholders of the closed block, and (b) unrealized gain (loss) on available for sale securities allocated to the closed block.", "label": "Closed Block Assets and Liabilities, Effect on Other Comprehensive Income (Loss)", "terseLabel": "Amounts included in accumulated other comprehensive income (loss)" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesEffectOnOtherComprehensiveIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized": { "auth_ref": [ "r815", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The carrying amount of closed block liabilities in excess of the carrying amount of closed block assets at the date of demutualization (adjusted to eliminate the impact of related amounts in accumulated other comprehensive income).", "label": "Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized", "periodEndLabel": "Maximum future earnings to be recognized from Closed Block assets and liabilities, End of year", "periodStartLabel": "Maximum future earnings to be recognized from Closed Block assets and liabilities, Beginning of year", "totalLabel": "Maximum future earnings to be recognized from Closed Block assets and liabilities" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails", "http://principal.com/role/DisclosureClosedBlockChangeInMaximumFutureEarningsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized [Abstract]", "terseLabel": "Closed Block liabilities and assets designated to the Closed Block" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease": { "auth_ref": [ "r815", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) of closed block liabilities in excess of closed block assets at the date of demutualization.", "label": "Closed Block Assets and Liabilities Maximum Future Earnings to be Recognized, Period Increase (Decrease)", "negatedLabel": "Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges", "totalLabel": "Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustments" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockChangeInMaximumFutureEarningsDetails", "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Closed Block Assets and Liabilities, Maximum Future Earnings to be Recognized [Roll Forward]", "terseLabel": "Change in maximum future earnings of the Closed Block" } } }, "localname": "ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockChangeInMaximumFutureEarningsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block" } } }, "localname": "ClosedBlockDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockDisclosureTextBlock": { "auth_ref": [ "r805", "r819" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure pertaining to the closed block.", "label": "Closed Block Disclosure [Text Block]", "terseLabel": "Closed Block" } } }, "localname": "ClosedBlockDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlock" ], "xbrltype": "textBlockItemType" }, "us-gaap_ClosedBlockLiabilities": { "auth_ref": [ "r816", "r817" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 2.0, "parentTag": "us-gaap_ExcessOfReportedClosedBlockLiabilitiesOverAssetsDesignatedToClosedBlock", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "For the segregated group of participating or dividend-paying policies and contracts along with the assets backing them (known as a closed block), the total of future policy benefits, policyholder account balance, policyholder dividend obligation and any other closed block liabilities.", "label": "Closed Block Liabilities", "totalLabel": "Total Closed Block liabilities" } } }, "localname": "ClosedBlockLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block Liabilities [Abstract]", "terseLabel": "Closed Block liabilities" } } }, "localname": "ClosedBlockLiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockLiabilitiesFuturePolicyBenefitsAndPolicyholderAccountBalances": { "auth_ref": [ "r809", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The liability as of the balance sheet date for future benefits to be paid to or on behalf of policyholders and expenses, less the present value of future net premiums payable under the insurance contracts and the policy cash accumulations, for the segregated group of participating or dividend-paying policies and contracts identified as a closed block.", "label": "Closed Block Liabilities, Future Policy Benefits and Policyholder Account Balances", "terseLabel": "Closed Block liabilities: Future policy benefits and claims" } } }, "localname": "ClosedBlockLiabilitiesFuturePolicyBenefitsAndPolicyholderAccountBalances", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockLiabilitiesOtherClosedBlockLiabilities": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 5.0, "parentTag": "us-gaap_ClosedBlockLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liabilities allocated to the closed block, classified as other.", "label": "Closed Block Liabilities, Other Closed Block Liabilities", "terseLabel": "Closed Block liabilities: Other liabilities" } } }, "localname": "ClosedBlockLiabilitiesOtherClosedBlockLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockLiabilitiesOtherPolicyholderFunds": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of closed block policyholder funds held, which are refundable.", "label": "Closed Block Liabilities, Other Policyholder Funds", "terseLabel": "Closed Block liabilities: Other policyholder funds" } } }, "localname": "ClosedBlockLiabilitiesOtherPolicyholderFunds", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockLiabilitiesPolicyholderDividendObligation": { "auth_ref": [ "r810", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 4.0, "parentTag": "us-gaap_ClosedBlockLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The liability as of the balance sheet date for the excess of the cumulative actual closed block earnings over the cumulative expected (actuarially determined) closed block earnings (each) for the period from the actuarial calculation date to the date of measurement. The excess will result in future dividends to closed block policyholders, unless offset by less favorable than expected future performance of the closed block. The policyholder dividend obligation, which may not have a negative balance, recognizes that a portion of earnings in certain cases will not inure to the stockholders of the insurance entity.", "label": "Closed Block Liabilities, Policyholder Dividend Obligation", "terseLabel": "Closed Block liabilities: Policyholder dividends obligation" } } }, "localname": "ClosedBlockLiabilitiesPolicyholderDividendObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockLiabilitiesPolicyholderDividendsPayable": { "auth_ref": [ "r814", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 3.0, "parentTag": "us-gaap_ClosedBlockLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of dividends payable as of the balance sheet date to policyholders of contracts in the closed block.", "label": "Closed Block Liabilities, Policyholder Dividends Payable", "terseLabel": "Closed Block liabilities: Policyholder dividends payable" } } }, "localname": "ClosedBlockLiabilitiesPolicyholderDividendsPayable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsBenefitsAndExpense": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockOperationsResultsBeforeIncomeTaxes", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits, claims and expenses that are related to an insurance entity's segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block). Includes, but is not limited to, death benefits, matured endowments, participating dividends, general expenses and deferred acquisition costs related to the closed block.", "label": "Closed Block Operations, Benefits and Expense", "totalLabel": "Closed Block: Total expenses" } } }, "localname": "ClosedBlockOperationsBenefitsAndExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsBenefitsAndExpenseAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block Operations, Benefits and Expense [Abstract]", "terseLabel": "Expenses" } } }, "localname": "ClosedBlockOperationsBenefitsAndExpenseAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockOperationsIncomeTaxes": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockOperationsNetResults", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of income tax expense or benefit allocated to the operations of the closed block for the period.", "label": "Closed Block Operations, Income Taxes", "terseLabel": "Closed Block: Income taxes (benefits)" } } }, "localname": "ClosedBlockOperationsIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsNetInvestmentIncome": { "auth_ref": [ "r812" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockOperationsRevenue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Income for the period from the investments allocated to an insurance entity's segregated group of participating or dividend-paying policies and contracts (known as a closed block), net of investment expenses, which are typically reported in a table of closed block operations.", "label": "Closed Block Operations, Net Investment Income", "terseLabel": "Closed Block: Net investment income (loss)" } } }, "localname": "ClosedBlockOperationsNetInvestmentIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsNetResults": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognizedPeriodIncreaseDecrease", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of net income (loss) from operations of the closed block.", "label": "Closed Block Operations, Net Results", "totalLabel": "Closed Block revenues, net of Closed Block expenses and income taxes" } } }, "localname": "ClosedBlockOperationsNetResults", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsNetResultsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block Operations, Net Results [Abstract]", "terseLabel": "Closed Block revenues and expenses" } } }, "localname": "ClosedBlockOperationsNetResultsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ClosedBlockOperationsNetResultsTableTextBlock": { "auth_ref": [ "r806" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the closed block operations.", "label": "Closed Block Operations, Net Results [Table Text Block]", "terseLabel": "Closed Block Revenues and Expenses (Table)" } } }, "localname": "ClosedBlockOperationsNetResultsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ClosedBlockOperationsPolicyholderDividends": { "auth_ref": [ "r814" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 2.0, "parentTag": "us-gaap_ClosedBlockOperationsBenefitsAndExpense", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "An expense for the period representing distributions paid or accrued for the segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block), which may be presented in a table of closed block operations as part of summarized financial data.", "label": "Closed Block Operations, Policyholder Dividends", "terseLabel": "Closed Block: Dividends to policyholders" } } }, "localname": "ClosedBlockOperationsPolicyholderDividends", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsPremiums": { "auth_ref": [ "r811" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockOperationsRevenue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "For the segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block), revenue for the period from insurance policy premiums; typically included in a table of closed block operations.", "label": "Closed Block Operations, Premiums", "terseLabel": "Closed Block: Premiums and other considerations" } } }, "localname": "ClosedBlockOperationsPremiums", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsRealizedInvestmentGainsLosses": { "auth_ref": [ "r813" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 3.0, "parentTag": "us-gaap_ClosedBlockOperationsRevenue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Gains and losses realized for the period from the investments allocated to an insurance entity's segregated group of participating or dividend-paying policies and contracts (known as a closed block).", "label": "Closed Block Operations, Realized Investment Gains (Losses)", "terseLabel": "Closed Block: Net realized capital gains (losses)" } } }, "localname": "ClosedBlockOperationsRealizedInvestmentGainsLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsResultsBeforeIncomeTaxes": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockOperationsNetResults", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The revenues less expenses from operations of the closed block during the period, before income taxes allocated thereto.", "label": "Closed Block Operations, Results before Income Taxes", "totalLabel": "Closed Block revenues, net of Closed Block expenses, before income taxes" } } }, "localname": "ClosedBlockOperationsResultsBeforeIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsRevenue": { "auth_ref": [ "r806" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockOperationsResultsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Total revenues from an insurance company's segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block).", "label": "Closed Block Operations, Revenue", "totalLabel": "Closed Block: Total revenues" } } }, "localname": "ClosedBlockOperationsRevenue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ClosedBlockOperationsRevenueAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Closed Block Operations, Revenue [Abstract]", "terseLabel": "Revenues" } } }, "localname": "ClosedBlockOperationsRevenueAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockRevenuesAndExpensesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CollateralAlreadyPostedAggregateFairValue": { "auth_ref": [ "r566" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.", "label": "Collateral Already Posted, Aggregate Fair Value", "terseLabel": "Collateral and initial margin posted supporting derivatives with credit-risk-related contingent features that were in a liability position" } } }, "localname": "CollateralAlreadyPostedAggregateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CollateralizedDebtObligationsMember": { "auth_ref": [ "r222", "r385" ], "lang": { "en-US": { "role": { "documentation": "Securities collateralized by a pool of assets.", "label": "Collateralized Debt Obligations [Member]", "terseLabel": "Collateralized debt obligations" } } }, "localname": "CollateralizedDebtObligationsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CommercialMortgageBackedSecuritiesMember": { "auth_ref": [ "r228", "r385" ], "lang": { "en-US": { "role": { "documentation": "Securities collateralized by commercial real estate mortgage loans.", "label": "Commercial Mortgage Backed Securities [Member]", "terseLabel": "Commercial mortgage-backed securities" } } }, "localname": "CommercialMortgageBackedSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CommercialPaperMember": { "auth_ref": [ "r330" ], "lang": { "en-US": { "role": { "documentation": "Unsecured promissory note (generally negotiable) that provides institutions with short-term funds.", "label": "Commercial Paper [Member]", "terseLabel": "Commercial paper" } } }, "localname": "CommercialPaperMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CommercialRealEstatePortfolioSegmentMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Portfolio segment of the company's total financing receivables related to commercial real estate.", "label": "Commercial Real Estate Portfolio Segment [Member]", "terseLabel": "Commercial mortgage loans" } } }, "localname": "CommercialRealEstatePortfolioSegmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CommonStockDividendsPerShareDeclared": { "auth_ref": [ "r354" ], "lang": { "en-US": { "role": { "documentation": "Aggregate dividends declared during the period for each share of common stock outstanding.", "label": "Common Stock, Dividends, Per Share, Declared", "terseLabel": "Dividends declared per common share (in dollars per share)" } } }, "localname": "CommonStockDividendsPerShareDeclared", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_CommonStockMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Stock that is subordinate to all other stock of the issuer.", "label": "Common Stock [Member]", "terseLabel": "Common stock" } } }, "localname": "CommonStockMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_CommonStockParOrStatedValuePerShare": { "auth_ref": [ "r26" ], "lang": { "en-US": { "role": { "documentation": "Face amount or stated value per share of common stock.", "label": "Common Stock, Par or Stated Value Per Share", "terseLabel": "Common stock, par value (in dollars per share)" } } }, "localname": "CommonStockParOrStatedValuePerShare", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "perShareItemType" }, "us-gaap_CommonStockSharesAuthorized": { "auth_ref": [ "r26" ], "lang": { "en-US": { "role": { "documentation": "The maximum number of common shares permitted to be issued by an entity's charter and bylaws.", "label": "Common Stock, Shares Authorized", "terseLabel": "Common stock, authorized (in shares)" } } }, "localname": "CommonStockSharesAuthorized", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "sharesItemType" }, "us-gaap_CommonStockSharesIssued": { "auth_ref": [ "r26" ], "lang": { "en-US": { "role": { "documentation": "Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.", "label": "Common Stock, Shares, Issued", "terseLabel": "Common stock, issued (in shares)" } } }, "localname": "CommonStockSharesIssued", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "sharesItemType" }, "us-gaap_CommonStockSharesOutstanding": { "auth_ref": [ "r26", "r347" ], "lang": { "en-US": { "role": { "documentation": "Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.", "label": "Common Stock, Shares, Outstanding", "terseLabel": "Common stock, outstanding (in shares)" } } }, "localname": "CommonStockSharesOutstanding", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "sharesItemType" }, "us-gaap_CommonStockValue": { "auth_ref": [ "r26" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_StockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.", "label": "Common Stock, Value, Issued", "terseLabel": "Common stock", "verboseLabel": "Common stock, par value $0.01 per share - 2,500.0 million shares authorized, 479.3 million and 476.7 million shares issued, and 276.6 million and 279.5 million shares outstanding in 2019 and 2018" } } }, "localname": "CommonStockValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_CompensationAndRetirementDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Employee and Agent Benefits" } } }, "localname": "CompensationAndRetirementDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_ComponentsOfDeferredTaxAssetsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Components of Deferred Tax Assets [Abstract]", "terseLabel": "Deferred income tax assets:" } } }, "localname": "ComponentsOfDeferredTaxAssetsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Components of Deferred Tax Assets and Liabilities [Abstract]", "terseLabel": "Significant components of net deferred income taxes" } } }, "localname": "ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Components of Deferred Tax Liabilities [Abstract]", "terseLabel": "Deferred income tax liabilities:" } } }, "localname": "ComponentsOfDeferredTaxLiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ComprehensiveIncomeNetOfTax": { "auth_ref": [ "r75", "r77", "r78" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.", "label": "Comprehensive Income (Loss), Net of Tax, Attributable to Parent", "totalLabel": "Comprehensive income (loss) attributable to Principal Financial Group, Inc." } } }, "localname": "ComprehensiveIncomeNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest": { "auth_ref": [ "r75", "r77", "r514", "r515", "r530" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 2.0, "parentTag": "us-gaap_ComprehensiveIncomeNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.", "label": "Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest", "terseLabel": "Comprehensive income (loss) attributable to noncontrolling interest" } } }, "localname": "ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest": { "auth_ref": [ "r75", "r77", "r513", "r530" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 1.0, "parentTag": "us-gaap_ComprehensiveIncomeNetOfTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.", "label": "Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest", "totalLabel": "Comprehensive income (loss)" } } }, "localname": "ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]", "terseLabel": "Other Comprehensive Income (Loss)" } } }, "localname": "ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock": { "auth_ref": [ "r143", "r510" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.", "label": "Condensed Financial Information of Parent Company Only Disclosure [Text Block]", "terseLabel": "Schedule II - Condensed Financial Information of Registrant (Parent Only)" } } }, "localname": "CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnly" ], "xbrltype": "textBlockItemType" }, "us-gaap_ConsolidationPolicyTextBlock": { "auth_ref": [ "r128", "r518", "r531", "r532" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.", "label": "Consolidation, Policy [Policy Text Block]", "terseLabel": "Consolidation - Policy" } } }, "localname": "ConsolidationPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_CorporateDebtSecuritiesMember": { "auth_ref": [ "r385", "r418", "r799" ], "lang": { "en-US": { "role": { "documentation": "Debt securities issued by domestic or foreign corporate business, banks and other entities with a promise of repayment.", "label": "Corporate Debt Securities [Member]", "terseLabel": "Corporate debt securities" } } }, "localname": "CorporateDebtSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CreditDefaultSwapMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A type of swap transaction used as a credit derivative in which one party makes periodic payments to the other and receives the promise of a pay-off if a third party defaults.", "label": "Credit Default Swap [Member]", "terseLabel": "Credit default swaps" } } }, "localname": "CreditDefaultSwapMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CreditDerivativeMaximumExposureUndiscounted": { "auth_ref": [ "r571" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.", "label": "Credit Derivative, Maximum Exposure, Undiscounted", "terseLabel": "Maximum future payments" } } }, "localname": "CreditDerivativeMaximumExposureUndiscounted", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CreditDerivativesByContractTypeAxis": { "auth_ref": [ "r569" ], "lang": { "en-US": { "role": { "documentation": "Information by major type of contract of credit derivatives.", "label": "Credit Derivatives Contract Type [Axis]" } } }, "localname": "CreditDerivativesByContractTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CreditDerivativesContractTypeDomain": { "auth_ref": [ "r569" ], "lang": { "en-US": { "role": { "documentation": "Represents major types of credit derivative contracts.", "label": "Credit Derivatives Contract Type [Domain]", "terseLabel": "Credit Derivatives Contract Type [Domain]" } } }, "localname": "CreditDerivativesContractTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CreditDerivativesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Credit Derivatives [Line Items]", "terseLabel": "Credit derivatives sold disclosures" } } }, "localname": "CreditDerivativesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "stringItemType" }, "us-gaap_CreditRiskContractMember": { "auth_ref": [ "r385", "r558" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to the creditworthiness or the credit spread of an entity.", "label": "Credit Risk Contract [Member]", "terseLabel": "Credit contracts" } } }, "localname": "CreditRiskContractMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1": { "auth_ref": [ "r151" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of the cumulative effect on retained earnings net of related income tax effect.", "label": "Cumulative Effect on Retained Earnings, Net of Tax", "terseLabel": "Effects of implementation of accounting change related to intra-entity asset transfer taxes, net", "verboseLabel": "Cumulative effect adjustment, increase to retained earnings" } } }, "localname": "CumulativeEffectOnRetainedEarningsNetOfTax1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_CurrencySwapMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Swap involving the exchange of principal and interest in one currency for another currency.", "label": "Currency Swap [Member]", "terseLabel": "Currency swaps" } } }, "localname": "CurrencySwapMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_CurrentFederalTaxExpenseBenefit": { "auth_ref": [ "r131", "r490", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 1.0, "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Current Federal Tax Expense (Benefit)", "verboseLabel": "Current income taxes (benefits): U.S. federal" } } }, "localname": "CurrentFederalTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CurrentForeignTaxExpenseBenefit": { "auth_ref": [ "r138", "r492" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 3.0, "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of current foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Current Foreign Tax Expense (Benefit)", "terseLabel": "Current income taxes (benefits): Foreign" } } }, "localname": "CurrentForeignTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CurrentIncomeTaxExpenseBenefit": { "auth_ref": [ "r131", "r490", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 1.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.", "label": "Current Income Tax Expense (Benefit)", "totalLabel": "Total current income taxes (benefits)" } } }, "localname": "CurrentIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CurrentStateAndLocalTaxExpenseBenefit": { "auth_ref": [ "r131", "r490", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 2.0, "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Current State and Local Tax Expense (Benefit)", "terseLabel": "Current income taxes (benefits): State" } } }, "localname": "CurrentStateAndLocalTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_CustomerRelationshipsMember": { "auth_ref": [ "r507" ], "lang": { "en-US": { "role": { "documentation": "Customer relationship that exists between an entity and its customer, for example, but not limited to, tenant relationships.", "label": "Customer Relationships [Member]", "terseLabel": "Customer relationships" } } }, "localname": "CustomerRelationshipsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DebtDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Debt" } } }, "localname": "DebtDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_DebtDisclosureTextBlock": { "auth_ref": [ "r336" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.", "label": "Debt Disclosure [Text Block]", "terseLabel": "Debt" } } }, "localname": "DebtDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebt" ], "xbrltype": "textBlockItemType" }, "us-gaap_DebtInstrumentAxis": { "auth_ref": [ "r17", "r19", "r20", "r659", "r663", "r692" ], "lang": { "en-US": { "role": { "documentation": "Information by type of debt instrument, including, but not limited to, draws against credit facilities.", "label": "Debt Instrument [Axis]" } } }, "localname": "DebtInstrumentAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DebtInstrumentBasisSpreadOnVariableRate1": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage points added to the reference rate to compute the variable rate on the debt instrument.", "label": "Debt Instrument, Basis Spread on Variable Rate", "verboseLabel": "Spread added to floating reference interest rate (as a percent)" } } }, "localname": "DebtInstrumentBasisSpreadOnVariableRate1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DebtInstrumentCarryingAmount": { "auth_ref": [ "r20", "r333", "r663", "r692" ], "calculation": { "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails": { "order": 2.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.", "label": "Long-term Debt, Gross", "terseLabel": "Long-term debt principal", "verboseLabel": "Outstanding principal balances" } } }, "localname": "DebtInstrumentCarryingAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtInstrumentDescriptionOfVariableRateBasis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.", "label": "Debt Instrument, Description of Variable Rate Basis", "verboseLabel": "Reference rate for floating rate of debt instrument" } } }, "localname": "DebtInstrumentDescriptionOfVariableRateBasis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DebtInstrumentFaceAmount": { "auth_ref": [ "r621", "r623" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Face (par) amount of debt instrument at time of issuance.", "label": "Debt Instrument, Face Amount", "verboseLabel": "Long-term debt issued" } } }, "localname": "DebtInstrumentFaceAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtInstrumentInterestRateStatedPercentage": { "auth_ref": [ "r42" ], "lang": { "en-US": { "role": { "documentation": "Contractual interest rate for funds borrowed, under the debt agreement.", "label": "Debt Instrument, Interest Rate, Stated Percentage", "terseLabel": "Interest rate (as a percent)" } } }, "localname": "DebtInstrumentInterestRateStatedPercentage", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DebtInstrumentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Debt Instrument [Line Items]", "terseLabel": "Long-Term Debt" } } }, "localname": "DebtInstrumentLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DebtInstrumentNameDomain": { "auth_ref": [ "r44" ], "lang": { "en-US": { "role": { "documentation": "The name for the particular debt instrument or borrowing that distinguishes it from other debt instruments or borrowings, including draws against credit facilities.", "label": "Debt Instrument Name [Domain]", "terseLabel": "Long-Term Debt Issuances [Domain]" } } }, "localname": "DebtInstrumentNameDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DebtInstrumentTable": { "auth_ref": [ "r44", "r135", "r348", "r351", "r352", "r353", "r620", "r621", "r623", "r683" ], "lang": { "en-US": { "role": { "documentation": "A table or schedule providing information pertaining to long-term debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer.", "label": "Schedule of Long-term Debt Instruments [Table]" } } }, "localname": "DebtInstrumentTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureDebtNonRecourseMortgagesAndNotesPayableDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DebtInstrumentTerm": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Debt Instrument, Term", "terseLabel": "Term of credit facility" } } }, "localname": "DebtInstrumentTerm", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "durationItemType" }, "us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet": { "auth_ref": [ "r334", "r622" ], "calculation": { "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails": { "order": 1.0, "parentTag": "us-gaap_LongTermDebt", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of unamortized debt discount (premium) and debt issuance costs.", "label": "Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net", "negatedLabel": "Net unamortized discount, premium and debt issuance costs" } } }, "localname": "DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount": { "auth_ref": [ "r43" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.", "label": "Debt Instrument, Unused Borrowing Capacity, Amount", "terseLabel": "Amount of notes issuable under option" } } }, "localname": "DebtInstrumentUnusedBorrowingCapacityAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtPolicyTextBlock": { "auth_ref": [ "r128", "r331" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy related to debt. Includes, but is not limited to, debt issuance costs, the effects of refinancings, method of amortizing debt issuance costs and original issue discount, and classifications of debt.", "label": "Debt, Policy [Policy Text Block]", "terseLabel": "Long-Term Debt - Policy" } } }, "localname": "DebtPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger": { "auth_ref": [ "r233", "r276", "r279" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": 1.0, "parentTag": "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer", "terseLabel": "Fixed maturities, Greater than or equal to twelve months, Fair value" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss": { "auth_ref": [ "r233", "r276" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": 1.0, "parentTag": "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss", "terseLabel": "Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions": { "auth_ref": [ "r274" ], "lang": { "en-US": { "role": { "documentation": "Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Twelve Months or Longer" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "integerItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months": { "auth_ref": [ "r233", "r276", "r279" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": 2.0, "parentTag": "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months", "terseLabel": "Fixed maturities, Less than twelve months, Fair value" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss": { "auth_ref": [ "r233", "r276" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": 2.0, "parentTag": "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss", "terseLabel": "Fixed maturities, Less than twelve months, Gross unrealized losses" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions": { "auth_ref": [ "r274" ], "lang": { "en-US": { "role": { "documentation": "Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions", "terseLabel": "Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less Than Twelve Months" } } }, "localname": "DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "integerItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput": { "auth_ref": [ "r591" ], "lang": { "en-US": { "role": { "documentation": "Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Debt Securities, Available-for-sale, Measurement Input", "terseLabel": "Fixed maturities, available-for-sale, Input" } } }, "localname": "DebtSecuritiesAvailableForSaleMeasurementInput", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "decimalItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleRealizedGain": { "auth_ref": [ "r240" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 1.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Debt Securities, Available-for-sale, Realized Gain", "verboseLabel": "Fixed maturities, available-for-sale: Gross gains" } } }, "localname": "DebtSecuritiesAvailableForSaleRealizedGain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleRealizedLossExcludingOtherThanTemporaryImpairment": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 2.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), excluding other-than-temporary impairment (OTTI).", "label": "Debt Securities, Available-for-sale, Realized Loss, Excluding Other-than-temporary Impairment", "negatedLabel": "Fixed maturities, available-for-sale: Gross losses" } } }, "localname": "DebtSecuritiesAvailableForSaleRealizedLossExcludingOtherThanTemporaryImpairment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition": { "auth_ref": [ "r230", "r272", "r279" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.", "label": "Debt Securities, Available-for-sale, Unrealized Loss Position", "totalLabel": "Fixed maturities, Total, Fair value" } } }, "localname": "DebtSecuritiesAvailableForSaleUnrealizedLossPosition", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss": { "auth_ref": [ "r231", "r273" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.", "label": "Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss", "totalLabel": "Fixed maturities, Total, Gross unrealized losses" } } }, "localname": "DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesAvailableForSaleValuationTechniqueExtensibleList": { "auth_ref": [ "r590" ], "lang": { "en-US": { "role": { "documentation": "Indicates valuation technique for measuring investment in debt security at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Debt Securities, Available-for-sale, Valuation Technique [Extensible List]", "terseLabel": "Fixed maturities, available-for-sale, Valuation technique" } } }, "localname": "DebtSecuritiesAvailableForSaleValuationTechniqueExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_DebtSecuritiesMember": { "auth_ref": [ "r242" ], "lang": { "en-US": { "role": { "documentation": "Debt instrument issued by corporations, governments and governmental agencies, municipalities, and other institutions.", "label": "Debt Securities [Member]", "terseLabel": "Fixed maturities" } } }, "localname": "DebtSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DebtSecuritiesTradingRealizedGainLoss": { "auth_ref": [ "r87" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 5.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).", "label": "Debt Securities, Trading, Realized Gain (Loss)", "terseLabel": "Fixed maturities, trading" } } }, "localname": "DebtSecuritiesTradingRealizedGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DebtSecuritiesTradingUnrealizedGainLoss": { "auth_ref": [ "r241" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).", "label": "Debt Securities, Trading, Unrealized Gain (Loss)", "terseLabel": "Unrealized gains (losses) on fixed maturities, trading" } } }, "localname": "DebtSecuritiesTradingUnrealizedGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredFederalIncomeTaxExpenseBenefit": { "auth_ref": [ "r131", "r491", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 1.0, "parentTag": "us-gaap_DeferredIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Deferred Federal Income Tax Expense (Benefit)", "terseLabel": "Deferred income taxes (benefits): U.S. federal" } } }, "localname": "DeferredFederalIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredForeignIncomeTaxExpenseBenefit": { "auth_ref": [ "r131", "r491", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 3.0, "parentTag": "us-gaap_DeferredIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Deferred Foreign Income Tax Expense (Benefit)", "terseLabel": "Deferred income taxes (benefits): Foreign" } } }, "localname": "DeferredForeignIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredIncomeTaxAssetsNet": { "auth_ref": [ "r484" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 6.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.", "label": "Deferred Income Tax Assets, Net", "terseLabel": "Deferred income tax assets", "verboseLabel": "Net deferred income tax assets" } } }, "localname": "DeferredIncomeTaxAssetsNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredIncomeTaxExpenseBenefit": { "auth_ref": [ "r118", "r131", "r491", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 2.0, "parentTag": "us-gaap_IncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Deferred Income Tax Expense (Benefit)", "totalLabel": "Total deferred income taxes (benefits)" } } }, "localname": "DeferredIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredIncomeTaxLiabilities": { "auth_ref": [ "r22", "r23", "r480", "r661", "r691" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 2.0, "parentTag": "us-gaap_DeferredTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax liability attributable to taxable temporary differences.", "label": "Deferred Tax Liabilities, Gross", "negatedTotalLabel": "Total deferred income tax liabilities" } } }, "localname": "DeferredIncomeTaxLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredIncomeTaxLiabilitiesNet": { "auth_ref": [ "r464", "r484" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 7.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.", "label": "Deferred Income Tax Liabilities, Net", "negatedTerseLabel": "Net deferred income tax liabilities", "terseLabel": "Deferred income taxes" } } }, "localname": "DeferredIncomeTaxLiabilitiesNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense": { "auth_ref": [ "r118", "r684", "r733", "r747", "r749", "r752", "r777" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.", "label": "Deferred Policy Acquisition Cost, Amortization Expense", "negatedLabel": "Amortization of deferred acquisition costs", "terseLabel": "Amortization of deferred acquisition costs" } } }, "localname": "DeferredPolicyAcquisitionCostAmortizationExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredPolicyAcquisitionCostUnrealizedInvestmentGainLoss": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized investment gain (loss) which decreases (increases) deferred policy acquisition cost.", "label": "Deferred Policy Acquisition Cost, Unrealized Investment Gain (Loss)", "negatedLabel": "Adjustment related to unrealized (gains) losses on available-for-sale securities and derivative instruments" } } }, "localname": "DeferredPolicyAcquisitionCostUnrealizedInvestmentGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredPolicyAcquisitionCosts": { "auth_ref": [ "r711", "r749", "r750", "r752", "r777", "r820" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 12.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 5.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred policy acquisition cost capitalized on contract remaining in force.", "label": "Deferred Policy Acquisition Costs", "periodEndLabel": "Balance at end of year, deferred acquisition costs", "periodStartLabel": "Balance at beginning of year, deferred acquisition costs", "terseLabel": "Deferred acquisition costs" } } }, "localname": "DeferredPolicyAcquisitionCosts", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredPolicyAcquisitionCostsAdditions": { "auth_ref": [ "r749", "r752", "r777" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred policy acquisition cost capitalized.", "label": "Deferred Policy Acquisition Costs, Additions", "terseLabel": "Costs deferred during the year" } } }, "localname": "DeferredPolicyAcquisitionCostsAdditions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredPolicyAcquisitionCostsDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Deferred Acquisition Costs" } } }, "localname": "DeferredPolicyAcquisitionCostsDisclosuresAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit": { "auth_ref": [ "r131", "r491", "r496" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 2.0, "parentTag": "us-gaap_DeferredIncomeTaxExpenseBenefit", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.", "label": "Deferred State and Local Income Tax Expense (Benefit)", "terseLabel": "Deferred income taxes (benefits): State" } } }, "localname": "DeferredStateAndLocalIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsGross": { "auth_ref": [ "r481" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 1.0, "parentTag": "us-gaap_DeferredTaxAssetsNet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.", "label": "Deferred Tax Assets, Gross", "totalLabel": "Gross deferred income tax assets" } } }, "localname": "DeferredTaxAssetsGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsNet": { "auth_ref": [ "r482" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 1.0, "parentTag": "us-gaap_DeferredTaxLiabilities", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.", "label": "Deferred Tax Assets, Net of Valuation Allowance", "totalLabel": "Total deferred income tax assets" } } }, "localname": "DeferredTaxAssetsNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsOther": { "auth_ref": [ "r459", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 7.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.", "label": "Deferred Tax Assets, Other", "terseLabel": "Other deferred income tax assets" } } }, "localname": "DeferredTaxAssetsOther", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsTaxCreditCarryforwards": { "auth_ref": [ "r486", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 4.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards.", "label": "Deferred Tax Assets, Tax Credit Carryforwards", "terseLabel": "Tax credit carryforwards" } } }, "localname": "DeferredTaxAssetsTaxCreditCarryforwards", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits": { "auth_ref": [ "r457", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 5.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.", "label": "Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits", "terseLabel": "Employee benefits" } } }, "localname": "DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsPolicyholderLiabilities": { "auth_ref": [ "r457", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 1.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from estimated policyholder reserves, which will be deductible from future taxable income when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the tax deduction to be taken.", "label": "Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Policyholder Liabilities", "terseLabel": "Insurance liabilities" } } }, "localname": "DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsPolicyholderLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses": { "auth_ref": [ "r458", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 6.0, "parentTag": "us-gaap_DeferredTaxAssetsGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses on foreign currency transactions.", "label": "Deferred Tax Assets, Unrealized Currency Losses", "terseLabel": "Foreign currency translation" } } }, "localname": "DeferredTaxAssetsUnrealizedCurrencyLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxAssetsValuationAllowance": { "auth_ref": [ "r483" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 2.0, "parentTag": "us-gaap_DeferredTaxAssetsNet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.", "label": "Deferred Tax Assets, Valuation Allowance", "negatedLabel": "Valuation allowance" } } }, "localname": "DeferredTaxAssetsValuationAllowance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxLiabilities": { "auth_ref": [ "r464", "r484" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.", "label": "Deferred Tax Liabilities, Net", "negatedTotalLabel": "Total net deferred income tax liabilities" } } }, "localname": "DeferredTaxLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets": { "auth_ref": [ "r459", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 5.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.", "label": "Deferred Tax Liabilities, Intangible Assets", "negatedLabel": "Intangible assets" } } }, "localname": "DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxLiabilitiesNetAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Deferred Tax Liabilities, Net, Classification [Abstract]", "terseLabel": "Net deferred income taxes by jurisdiction" } } }, "localname": "DeferredTaxLiabilitiesNetAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DeferredTaxLiabilitiesOther": { "auth_ref": [ "r459", "r488", "r489" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 7.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax liability attributable to taxable temporary differences classified as other.", "label": "Deferred Tax Liabilities, Other", "negatedLabel": "Other deferred income tax liabilities" } } }, "localname": "DeferredTaxLiabilitiesOther", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DeferredTaxLiabilitiesOtherComprehensiveIncome": { "auth_ref": [ "r459", "r488", "r489", "r499" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails": { "order": 3.0, "parentTag": "us-gaap_DeferredIncomeTaxLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains in other comprehensive income.", "label": "Deferred Tax Liabilities, Other Comprehensive Income", "negatedLabel": "Net unrealized gains on available-for-sale securities" } } }, "localname": "DeferredTaxLiabilitiesOtherComprehensiveIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities": { "auth_ref": [ "r368", "r382", "r662", "r702" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 3.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liability, recognized in statement of financial position, for defined benefit pension plan. Excludes other postretirement benefit plan.", "label": "Defined Benefit Pension Plan, Liabilities", "terseLabel": "Pension liability" } } }, "localname": "DefinedBenefitPensionPlanCurrentAndNoncurrentLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation": { "auth_ref": [ "r387" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.", "label": "Defined Benefit Plan, Accumulated Benefit Obligation", "terseLabel": "Accumulated benefit obligation" } } }, "localname": "DefinedBenefitPlanAccumulatedBenefitObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax": { "auth_ref": [ "r63", "r69" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).", "label": "Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax", "totalLabel": "Pre-tax accumulated other comprehensive (income) loss" } } }, "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]", "terseLabel": "Amount recognized in accumulated other comprehensive (income) loss" } } }, "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax": { "auth_ref": [ "r69", "r397" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": 1.0, "parentTag": "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.", "label": "Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax", "negatedLabel": "Total net actuarial (gain) loss", "negatedTerseLabel": "Total net actuarial loss" } } }, "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax": { "auth_ref": [ "r69", "r397" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": 2.0, "parentTag": "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).", "label": "Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax", "terseLabel": "Prior service (benefit) cost", "verboseLabel": "Prior service benefit" } } }, "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets": { "auth_ref": [ "r378", "r418" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.", "label": "Defined Benefit Plan, Actual Return on Plan Assets", "terseLabel": "Actual return on plan assets", "verboseLabel": "Asset gain on plan assets" } } }, "localname": "DefinedBenefitPlanActualReturnOnPlanAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanActuarialGainLoss": { "auth_ref": [ "r374" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.", "label": "Defined Benefit Plan, Actuarial Gain (Loss)", "terseLabel": "Actuarial gain (loss)" } } }, "localname": "DefinedBenefitPlanActuarialGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses": { "auth_ref": [ "r394", "r415", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": 5.0, "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.", "label": "Defined Benefit Plan, Amortization of Gains (Losses)", "negatedLabel": "Recognized net actuarial (gain) loss" } } }, "localname": "DefinedBenefitPlanAmortizationOfGainsLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit": { "auth_ref": [ "r395", "r416", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": 4.0, "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan.", "label": "Defined Benefit Plan, Amortization of Prior Service Cost (Credit)", "terseLabel": "Amortization of prior service (benefit) cost" } } }, "localname": "DefinedBenefitPlanAmortizationOfPriorServiceCostCredit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet": { "auth_ref": [ "r368", "r382" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.", "label": "Defined Benefit Plan, Amounts Recognized in Balance Sheet", "totalLabel": "Total assets (liabilities) recognized in statement of financial position" } } }, "localname": "DefinedBenefitPlanAmountsRecognizedInBalanceSheet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]", "terseLabel": "Amount recognized in statement of financial position" } } }, "localname": "DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract]", "terseLabel": "Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year" } } }, "localname": "DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent": { "auth_ref": [ "r15", "r368", "r369", "r382", "r657", "r694" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": 1.0, "parentTag": "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.", "label": "Defined Benefit Plan, Assets for Plan Benefits", "terseLabel": "Amount recognized in other assets" } } }, "localname": "DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanAssetsTargetAllocationsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Assets, Target Allocations [Abstract]", "terseLabel": "Asset category target allocation" } } }, "localname": "DefinedBenefitPlanAssetsTargetAllocationsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanAssumedHealthCareCostTrendRatesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]", "terseLabel": "Assumed Health Care Cost Trend Rates" } } }, "localname": "DefinedBenefitPlanAssumedHealthCareCostTrendRatesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate": { "auth_ref": [ "r398" ], "lang": { "en-US": { "role": { "documentation": "Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.", "label": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate", "terseLabel": "Discount rate: Benefit obligation (as a percent)" } } }, "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease": { "auth_ref": [ "r399" ], "lang": { "en-US": { "role": { "documentation": "Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.", "label": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase", "terseLabel": "Rate of compensation increase: Benefit obligation (as a percent)" } } }, "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate": { "auth_ref": [ "r398" ], "lang": { "en-US": { "role": { "documentation": "Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.", "label": "Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate", "terseLabel": "Discount rate: Net periodic benefit cost (as a percent)" } } }, "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets": { "auth_ref": [ "r400" ], "lang": { "en-US": { "role": { "documentation": "Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.", "label": "Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets", "terseLabel": "Expected long-term return on plan assets: Net periodic benefit cost (as a percent)" } } }, "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease": { "auth_ref": [ "r399" ], "lang": { "en-US": { "role": { "documentation": "Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.", "label": "Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase", "terseLabel": "Rate of compensation increase: Net periodic benefit cost (as a percent)" } } }, "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanBenefitObligation": { "auth_ref": [ "r370" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusCalc2Details": { "order": 1.0, "parentTag": "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.", "label": "Defined Benefit Plan, Benefit Obligation", "negatedPeriodEndLabel": "Benefit obligation at end of year", "negatedPeriodStartLabel": "Benefit obligation at beginning of year" } } }, "localname": "DefinedBenefitPlanBenefitObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid": { "auth_ref": [ "r375", "r419" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.", "label": "Defined Benefit Plan, Benefit Obligation, Benefits Paid", "terseLabel": "Benefits paid" } } }, "localname": "DefinedBenefitPlanBenefitObligationBenefitsPaid", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant": { "auth_ref": [ "r373" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of contributions received by defined benefit plan from participant which increase benefit obligation.", "label": "Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant", "negatedLabel": "Participant contributions" } } }, "localname": "DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in benefit obligation of defined benefit plan.", "label": "Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)", "terseLabel": "Increase in benefit obligation" } } }, "localname": "DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis": { "auth_ref": [ "r385", "r386", "r403", "r418" ], "lang": { "en-US": { "role": { "documentation": "Information by defined benefit plan asset investment.", "label": "Defined Benefit Plan, Asset Categories [Axis]" } } }, "localname": "DefinedBenefitPlanByPlanAssetCategoriesAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember": { "auth_ref": [ "r385" ], "lang": { "en-US": { "role": { "documentation": "Cash and cash equivalent in which defined benefit plan asset is invested.", "label": "Defined Benefit Plan Cash And Cash Equivalents [Member]", "terseLabel": "Cash and cash equivalents" } } }, "localname": "DefinedBenefitPlanCashAndCashEquivalentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]", "terseLabel": "Change in benefit obligation" } } }, "localname": "DefinedBenefitPlanChangeInBenefitObligationRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]", "terseLabel": "Change in plan assets" } } }, "localname": "DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanContributionsByEmployer": { "auth_ref": [ "r379", "r385", "r386", "r417", "r418" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of contribution received by defined benefit plan from employer which increases plan assets.", "label": "Defined Benefit Plan, Contributions by Employer", "terseLabel": "Contributions made by employer to fund qualified and nonqualified pension plans", "verboseLabel": "Employer contribution" } } }, "localname": "DefinedBenefitPlanContributionsByEmployer", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanDebtSecurityMember": { "auth_ref": [ "r385" ], "lang": { "en-US": { "role": { "documentation": "Debt instrument issued by corporation, government and governmental agency, municipality, and other institution; in which defined benefit plan asset is invested.", "label": "Defined Benefit Plan Debt Security [Member]", "terseLabel": "Fixed income securities" } } }, "localname": "DefinedBenefitPlanDebtSecurityMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanDisclosureLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Defined Benefit Plan Disclosure [Line Items]", "terseLabel": "Defined Benefit Plan Disclosures" } } }, "localname": "DefinedBenefitPlanDisclosureLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]", "terseLabel": "Effect of one-percentage-point change in assumed health care cost trend rates" } } }, "localname": "DefinedBenefitPlanEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1": { "auth_ref": [ "r402" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate.", "label": "Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation", "terseLabel": "Effect on accumulated postretirement benefit obligation of a one-percentage-point decrease in assumed health care cost trend rates" } } }, "localname": "DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation": { "auth_ref": [ "r402" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate.", "label": "Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation", "negatedLabel": "Effect on accumulated postretirement benefit obligation of a one-percentage-point increase in assumed health care cost trend rates" } } }, "localname": "DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanEquitySecuritiesMember": { "auth_ref": [ "r385", "r418" ], "lang": { "en-US": { "role": { "documentation": "Security representing ownership in corporation or other legal entity for which ownership is represented by share of stock, in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant.", "label": "Defined Benefit Plan Equity Securities [Member]", "terseLabel": "Equity portfolios" } } }, "localname": "DefinedBenefitPlanEquitySecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember": { "auth_ref": [ "r385", "r386", "r418" ], "lang": { "en-US": { "role": { "documentation": "Security representing ownership in corporation or other legal entity, not domiciled in United States of America (US), for which ownership is represented by share of stock; in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant.", "label": "Defined Benefit Plan Equity Securities Non Us [Member]", "terseLabel": "International equity portfolios" } } }, "localname": "DefinedBenefitPlanEquitySecuritiesNonUsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember": { "auth_ref": [ "r385", "r418" ], "lang": { "en-US": { "role": { "documentation": "Security representing ownership in corporation or other legal entity, domiciled in United States of America (US), classified as having large market capitalization, for which ownership is represented by share of stock; in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant.", "label": "Defined Benefit Plan Equity Securities Us Large Cap [Member]", "terseLabel": "U.S. large cap equity portfolios" } } }, "localname": "DefinedBenefitPlanEquitySecuritiesUsLargeCapMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember": { "auth_ref": [ "r385", "r386", "r418" ], "lang": { "en-US": { "role": { "documentation": "Security representing ownership in corporation or other legal entity, domiciled in United States of America (US), for which ownership is represented by share of stock; in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant.", "label": "Defined Benefit Plan Equity Securities Us [Member]", "terseLabel": "U.S. equity portfolios" } } }, "localname": "DefinedBenefitPlanEquitySecuritiesUsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Estimated Future Benefit Payments" } } }, "localname": "DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanEstimatedFutureEmployerContributionsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Expected Future Employer Contributions [Abstract]", "terseLabel": "Contributions" } } }, "localname": "DefinedBenefitPlanEstimatedFutureEmployerContributionsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear": { "auth_ref": [ "r404" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position.", "label": "Defined Benefit Plan, Future Amortization of Gain (Loss)", "negatedLabel": "Estimated net actuarial (gain) loss that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year" } } }, "localname": "DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear": { "auth_ref": [ "r404" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount included in accumulated other comprehensive (income) loss for prior service cost (credit) expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position.", "label": "Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)", "terseLabel": "Estimated prior service cost (benefit) that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year" } } }, "localname": "DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter", "terseLabel": "Estimated future benefit payments, Years 6-10" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months", "terseLabel": "Estimated future benefit payments, Year 1" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Year Five", "terseLabel": "Estimated future benefit payments, Year 5" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Year Four", "terseLabel": "Estimated future benefit payments, Year 4" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Year Three", "terseLabel": "Estimated future benefit payments, Year 3" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo": { "auth_ref": [ "r388" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Benefit Payments, Year Two", "terseLabel": "Estimated future benefit payments, Year 2" } } }, "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear": { "auth_ref": [ "r389" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.", "label": "Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year", "terseLabel": "Possible contributions to be made during the next fiscal year to the qualified and nonqualified pension plans combined" } } }, "localname": "DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets": { "auth_ref": [ "r393", "r414", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": 3.0, "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.", "label": "Defined Benefit Plan, Expected Return on Plan Assets", "negatedLabel": "Expected return on plan assets" } } }, "localname": "DefinedBenefitPlanExpectedReturnOnPlanAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanFairValueOfPlanAssets": { "auth_ref": [ "r377", "r385", "r386", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusCalc2Details": { "order": 2.0, "parentTag": "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.", "label": "Defined Benefit Plan, Fair Value of Plan Assets", "periodEndLabel": "Fair value of plan assets at end of year", "periodStartLabel": "Fair value of plan assets at beginning of year", "terseLabel": "Fair value of plan assets" } } }, "localname": "DefinedBenefitPlanFairValueOfPlanAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanInterestCost": { "auth_ref": [ "r372", "r392", "r413", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": 2.0, "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cost recognized for passage of time related to defined benefit plan.", "label": "Defined Benefit Plan, Interest Cost", "negatedLabel": "Interest cost", "terseLabel": "Interest cost" } } }, "localname": "DefinedBenefitPlanInterestCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost": { "auth_ref": [ "r390", "r411", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 1.0, "parentTag": "us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax", "weight": 1.0 }, "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of net periodic benefit cost (credit) for defined benefit plan.", "label": "Defined Benefit Plan, Net Periodic Benefit Cost", "totalLabel": "Net periodic benefit cost (income)" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]", "terseLabel": "Components of Net Periodic Benefit Cost (Income)" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCostAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList": { "auth_ref": [ "r390", "r411" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of income or comprehensive income that includes amortization of gain (loss) component of net periodic benefit (cost) credit for defined benefit plan.", "label": "Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible List]", "terseLabel": "Recognized net actuarial (gain) loss, location on consolidated statements of operations" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncomeOrComprehensiveIncomeExtensibleList": { "auth_ref": [ "r390", "r411" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of income or comprehensive income that includes amortization of prior service cost (credit) component of net periodic benefit cost (credit) for defined benefit plan.", "label": "Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible List]", "terseLabel": "Amortization of prior service (benefit) cost, location on consolidated statements of operations" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncomeOrComprehensiveIncomeExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList": { "auth_ref": [ "r390", "r411" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of income or comprehensive income that includes expected return (loss) on plan asset component of net periodic benefit (cost) credit for defined benefit plan.", "label": "Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible List]", "terseLabel": "Expected return on plan assets, location on consolidated statements of operations" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList": { "auth_ref": [ "r390", "r411" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of income or comprehensive income that includes interest cost component of net periodic benefit cost (credit) for defined benefit plan.", "label": "Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible List]", "terseLabel": "Interest cost, location on consolidated statements of operations" } } }, "localname": "DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_DefinedBenefitPlanOtherChanges": { "auth_ref": [], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in benefit obligation of defined benefit plan from change, classified as other.", "label": "Defined Benefit Plan, Other Changes", "negatedLabel": "Other" } } }, "localname": "DefinedBenefitPlanOtherChanges", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]", "terseLabel": "Information for Defined Benefit Plans With an Accumulated Benefit Obligation in Excess of Plan Assets" } } }, "localname": "DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation": { "auth_ref": [ "r407", "r408", "r418" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.", "label": "Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation", "terseLabel": "Accumulated benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets" } } }, "localname": "DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets": { "auth_ref": [ "r407", "r408", "r418" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.", "label": "Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets", "terseLabel": "Fair value of plan assets for defined benefit plans with an accumulated benefit obligation in excess of plan assets" } } }, "localname": "DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation": { "auth_ref": [ "r407", "r418" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.", "label": "Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation", "terseLabel": "Projected benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets" } } }, "localname": "DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPlanAmendments": { "auth_ref": [ "r376" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan.", "label": "Defined Benefit Plan, Plan Amendments", "negatedLabel": "Plan amendments" } } }, "localname": "DefinedBenefitPlanPlanAmendments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid": { "auth_ref": [ "r381", "r419" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.", "label": "Defined Benefit Plan, Plan Assets, Benefits Paid", "negatedLabel": "Benefits paid" } } }, "localname": "DefinedBenefitPlanPlanAssetsBenefitsPaid", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant": { "auth_ref": [ "r380" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of contributions received by defined benefit plan from participant which increases plan assets.", "label": "Defined Benefit Plan, Plan Assets, Contributions by Plan Participant", "terseLabel": "Participant contributions" } } }, "localname": "DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage": { "auth_ref": [ "r384", "r418" ], "lang": { "en-US": { "role": { "documentation": "Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.", "label": "Defined Benefit Plan, Plan Assets, Target Allocation, Percentage", "terseLabel": "Asset category target allocation" } } }, "localname": "DefinedBenefitPlanPlanAssetsTargetAllocationPercentage", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanRealEstateMember": { "auth_ref": [ "r385", "r418" ], "lang": { "en-US": { "role": { "documentation": "Property composed of building, land and land improvement; in which defined benefit plan asset is invested.", "label": "Defined Benefit Plan Real Estate [Member]", "terseLabel": "Real estate investment portfolios" } } }, "localname": "DefinedBenefitPlanRealEstateMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DefinedBenefitPlanServiceCost": { "auth_ref": [ "r371", "r391", "r412", "r418" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails": { "order": 1.0, "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.", "label": "Defined Benefit Plan, Service Cost", "negatedLabel": "Service cost", "terseLabel": "Service cost" } } }, "localname": "DefinedBenefitPlanServiceCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1": { "auth_ref": [ "r401" ], "lang": { "en-US": { "role": { "documentation": "Ultimate trend rate for health care cost for defined benefit postretirement plan.", "label": "Defined Benefit Plan, Ultimate Health Care Cost Trend Rate", "terseLabel": "Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate) (as a percent)" } } }, "localname": "DefinedBenefitPlanUltimateHealthCareCostTrendRate1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]", "terseLabel": "Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section" } } }, "localname": "DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]", "terseLabel": "Weighted-average assumptions used to determine net periodic benefit cost" } } }, "localname": "DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable": { "auth_ref": [ "r405", "r406", "r409", "r410", "r418" ], "lang": { "en-US": { "role": { "documentation": "Disclosures and provisions pertaining to defined benefit pension plans or other postretirement defined benefit plans. The arrangements are generally based on terms and conditions stipulated by the entity, and which contain a promise by the employer to pay certain amounts or awards at designated future dates, including a period after retirement, upon compliance with stipulated requirements. Excludes disclosures pertaining to defined contribution plans.", "label": "Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table]" } } }, "localname": "DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]", "terseLabel": "Defined Benefit Plans and Other Postretirement Benefit Plans" } } }, "localname": "DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedContributionPlanDisclosureLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Defined Contribution Plan Disclosure [Line Items]", "terseLabel": "Defined Contribution Plan Disclosures" } } }, "localname": "DefinedContributionPlanDisclosureLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.", "label": "Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay", "terseLabel": "Maximum percent of participant's compensation matched by employer (as a percent)" } } }, "localname": "DefinedContributionPlanEmployerMatchingContributionPercent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Percentage employer matches of the employee's percentage contribution matched.", "label": "Defined Contribution Plan, Employer Matching Contribution, Percent of Match", "terseLabel": "Contribution rate of employer to match participant's contributions (as a percent)" } } }, "localname": "DefinedContributionPlanEmployerMatchingContributionPercentOfMatch", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "percentItemType" }, "us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount": { "auth_ref": [], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Maximum amount the employee may contribute to a defined contribution plan.", "label": "Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount", "terseLabel": "Maximum amount of compensation eligible participants could contribute to defined contribution plans" } } }, "localname": "DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DefinedContributionPlanTable": { "auth_ref": [ "r420" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about defined contribution pension plans or defined contribution other postretirement plans, separately for pension plans and other postretirement benefit plans.", "label": "Defined Contribution Plan [Table]" } } }, "localname": "DefinedContributionPlanTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DepositAccountMember": { "auth_ref": [ "r362" ], "lang": { "en-US": { "role": { "documentation": "Bank account at depository institution allowing money to be withdrawn or deposited by account holder.", "label": "Deposit Account [Member]", "terseLabel": "Deposit account fee revenue" } } }, "localname": "DepositAccountMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DepositContractsLiabilities": { "auth_ref": [ "r280" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 1.0, "parentTag": "pfg_ContractholderFunds", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Carrying amount of liabilities as of the balance sheet date pertaining to amounts received by the insurer or reinsurer from the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.", "label": "Deposit Contracts, Liabilities", "totalLabel": "Total liabilities for investment contracts" } } }, "localname": "DepositContractsLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DepositContractsLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Deposit Contracts, Liabilities [Abstract]", "terseLabel": "Liabilities for investment contracts:" } } }, "localname": "DepositContractsLiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_Deposits": { "auth_ref": [ "r669" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.", "label": "Deposits", "negatedLabel": "Bank deposits" } } }, "localname": "Deposits", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DepreciationAmortizationAndAccretionNet": { "auth_ref": [ "r118" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 1.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.", "label": "Depreciation, Amortization and Accretion, Net", "terseLabel": "Depreciation and amortization expense" } } }, "localname": "DepreciationAmortizationAndAccretionNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_DepreciationAndAmortization": { "auth_ref": [ "r118", "r307" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.", "label": "Depreciation, Depletion and Amortization, Nonproduction", "verboseLabel": "Depreciation and amortization expense" } } }, "localname": "DepreciationAndAmortization", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeAmountOfHedgedItem": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Amount of hedged item in hedging relationship. Excludes hedged asset or liability.", "label": "Derivative, Amount of Hedged Item", "terseLabel": "Amortized cost of hedged item - Active hedging relationships" } } }, "localname": "DerivativeAmountOfHedgedItem", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement": { "auth_ref": [ "r50" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 4.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.", "label": "Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement", "terseLabel": "Derivative instruments, assets" } } }, "localname": "DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeContractTypeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Financial instrument or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.", "label": "Derivative Contract Type [Domain]", "terseLabel": "Derivative Contract [Domain]" } } }, "localname": "DerivativeContractTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DerivativeFairValueHedgeIncludedInEffectivenessGainLoss": { "auth_ref": [ "r576" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) on derivative instrument designated and qualifying as fair value hedge included in assessment of hedge effectiveness, recognized in earnings.", "label": "Derivative, Fair Value Hedge, Included in Effectiveness, Gain (Loss)", "terseLabel": "Amortization of hedged item basis adjustments" } } }, "localname": "DerivativeFairValueHedgeIncludedInEffectivenessGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeFinancialInstrumentsAssetsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This element represents types of derivative financial instruments which are financial instruments or other contractual arrangements with all three of the following characteristics: (a) it has (1) one or more underlyings and (2) one or more notional amounts or payment provisions or both. Those terms determine the amount of the settlement or settlements, and, in some cases, whether or not a settlement is required; (b) it requires no initial net investment or an initial net investment that is smaller than would be required for other types of contracts that would be expected to have a similar response to changes in market factors; and (c) its terms require or permit net settlement, it can readily be settled net by a means outside the contract, or it provides for delivery of an asset that puts the recipient in a position not substantially different from net settlement. Notwithstanding the above characteristics, loan commitments that relate to the origination of mortgage loans that will be held for sale are accounted for as derivative instruments by the issuer of the loan commitment (that is, the potential lender).", "label": "Derivative Financial Instruments Assets [Member]", "terseLabel": "Derivative assets" } } }, "localname": "DerivativeFinancialInstrumentsAssetsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents derivative instrument obligations meeting the definition of a liability which are reported as of the balance sheet date. Derivative instrument obligations are generally measured at fair value, and adjustments to the carrying amount of hedged items reflect changes in their fair value (that is, losses) that are attributable to the risk being hedged and that arise while the hedge is in effect.", "label": "Derivative Financial Instruments Liabilities [Member]", "terseLabel": "Derivative liabilities" } } }, "localname": "DerivativeFinancialInstrumentsLiabilitiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DerivativeInstrumentRiskAxis": { "auth_ref": [ "r545", "r547", "r553", "r560" ], "lang": { "en-US": { "role": { "documentation": "Information by type of derivative contract.", "label": "Derivative Instrument [Axis]" } } }, "localname": "DerivativeInstrumentRiskAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Derivative Financial Instruments" } } }, "localname": "DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock": { "auth_ref": [ "r584" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.", "label": "Derivative Instruments and Hedging Activities Disclosure [Text Block]", "terseLabel": "Derivative Financial Instruments" } } }, "localname": "DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstruments" ], "xbrltype": "textBlockItemType" }, "us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Derivative Instruments and Hedging Activities Disclosures [Line Items]" } } }, "localname": "DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about derivatives and hedging activities.", "label": "Derivative Instruments and Hedging Activities Disclosures [Table]" } } }, "localname": "DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis": { "auth_ref": [ "r542", "r545", "r553" ], "lang": { "en-US": { "role": { "documentation": "Information by type of hedging relationship.", "label": "Hedging Relationship [Axis]" } } }, "localname": "DerivativeInstrumentsGainLossByHedgingRelationshipAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable": { "auth_ref": [ "r542", "r545", "r553", "r560", "r561", "r575", "r579" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about the location and amount of derivative instruments and nonderivative instruments designated as hedging instruments reported before netting adjustments, and the amount of gain (loss) on derivative instruments and nonderivative instruments designated and qualified as hedging instruments.", "label": "Derivative Instruments, Gain (Loss) [Table]" } } }, "localname": "DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsGainLossLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Derivative Instruments, Gain (Loss) [Line Items]", "terseLabel": "Effect of derivatives in hedging relationships and the related hedged items on the consolidated statements of operations", "verboseLabel": "Effect of derivatives not designated as hedging instruments on the consolidated statements of operations" } } }, "localname": "DerivativeInstrumentsGainLossLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet": { "auth_ref": [ "r552", "r554" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.", "label": "Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net", "terseLabel": "Amount of gain (loss) recognized in net income on derivatives" } } }, "localname": "DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement": { "auth_ref": [ "r50" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset.", "label": "Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement", "terseLabel": "Derivative instruments, liabilities" } } }, "localname": "DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeMember": { "auth_ref": [ "r534" ], "lang": { "en-US": { "role": { "documentation": "This element represents types of derivative financial instruments which are financial instruments or other contractual arrangements with all three of the following characteristics: (a) it has (1) one or more underlyings and (2) one or more notional amounts or payment provisions or both. Those terms determine the amount of the settlement or settlements, and, in some cases, whether or not a settlement is required; (b) it requires no initial net investment or an initial net investment that is smaller than would be required for other types of contracts that would be expected to have a similar response to changes in market factors; and (c) its terms require or permit net settlement, it can readily be settled net by a means outside the contract, or it provides for delivery of an asset that puts the recipient in a position not substantially different from net settlement. Notwithstanding the above characteristics, loan commitments that relate to the origination of mortgage loans that will be held for sale are accounted for as derivative instruments by the issuer of the loan commitment (that is, the potential lender).", "label": "Derivative [Member]", "terseLabel": "Derivatives" } } }, "localname": "DerivativeMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DerivativeNetLiabilityPositionAggregateFairValue": { "auth_ref": [ "r565" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.", "label": "Derivative, Net Liability Position, Aggregate Fair Value", "terseLabel": "Aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position" } } }, "localname": "DerivativeNetLiabilityPositionAggregateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativeNotionalAmount": { "auth_ref": [ "r536", "r538" ], "lang": { "en-US": { "role": { "documentation": "Nominal or face amount used to calculate payment on derivative.", "label": "Derivative, Notional Amount", "terseLabel": "Notional amount" } } }, "localname": "DerivativeNotionalAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DerivativesFairValueLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Derivatives, Fair Value [Line Items]", "terseLabel": "Derivatives, fair value disclosures" } } }, "localname": "DerivativesFairValueLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DerivativesPolicyTextBlock": { "auth_ref": [ "r128", "r140", "r535", "r537", "r542", "r543", "r574" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for its derivative instruments and hedging activities.", "label": "Derivatives, Policy [Policy Text Block]", "terseLabel": "Derivatives - Policy" } } }, "localname": "DerivativesPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_DesignatedAsHedgingInstrumentMember": { "auth_ref": [ "r542" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument designated as hedging instrument under Generally Accepted Accounting Principles (GAAP).", "label": "Designated As Hedging Instrument [Member]", "terseLabel": "Derivatives designated as hedging instruments" } } }, "localname": "DesignatedAsHedgingInstrumentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DirectPremiumsEarned": { "auth_ref": [ "r726", "r740", "r790", "r793" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 1.0, "parentTag": "us-gaap_PremiumsEarnedNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.", "label": "Direct Premiums Earned", "terseLabel": "Premiums gross amount", "verboseLabel": "Premiums and other considerations, Direct" } } }, "localname": "DirectPremiumsEarned", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DisaggregationOfRevenueAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Disaggregation of Revenue [Abstract]", "terseLabel": "Revenues from Contracts with Customers - Disaggregation of Revenues" } } }, "localname": "DisaggregationOfRevenueAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DisaggregationOfRevenueLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Disaggregation of Revenue [Line Items]", "terseLabel": "Disaggregation of Revenues", "verboseLabel": "Revenues from Contracts with Customers" } } }, "localname": "DisaggregationOfRevenueLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables" ], "xbrltype": "stringItemType" }, "us-gaap_DisaggregationOfRevenueTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about disaggregation of revenue into categories depicting how nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factor.", "label": "Disaggregation of Revenue [Table]" } } }, "localname": "DisaggregationOfRevenueTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables" ], "xbrltype": "stringItemType" }, "us-gaap_DisaggregationOfRevenueTableTextBlock": { "auth_ref": [ "r361" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of disaggregation of revenue into categories depicting how nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factor.", "label": "Disaggregation of Revenue [Table Text Block]", "terseLabel": "Disaggregation of Revenues from Contracts with Customers (Table)" } } }, "localname": "DisaggregationOfRevenueTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock": { "auth_ref": [ "r456" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for share-based payment arrangement.", "label": "Disclosure of Compensation Related Costs, Share-based Payments [Text Block]", "terseLabel": "Stock-Based Compensation Plans" } } }, "localname": "DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlans" ], "xbrltype": "textBlockItemType" }, "us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Stock-Based Compensation Plans" } } }, "localname": "DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_DisclosureOfCreditDerivativesTextBlock": { "auth_ref": [ "r568", "r572", "r573" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of credit derivatives which includes information by sellers of credit derivatives, about each credit derivative, or each group of similar credit derivatives, including (a) the nature of the credit derivative - its term, how it arose, the events or circumstances that would require the seller to perform under the credit derivative, and the current status of the payment/performance risk of the credit derivative; (b) the maximum potential amount of future payments (undiscounted) the seller could be required to make under the credit derivative; (c) the current fair value of the credit derivative; and (d) the nature of any recourse provisions under the credit derivative, and any assets held either as collateral or by third parties. A credit derivative is a derivative instrument (1) in which one or more of its underlyings are related to the credit risk of a specified entity (or a group of entities) or an index based on the credit risk of a group of entities and (2) that exposes the seller to potential loss from credit-risk-related events specified in the contract. Examples of credit derivatives within the scope of this paragraph include, but are not limited to, credit default swaps, credit spread options, and credit index products; also includes a hybrid instrument that has an embedded credit derivative (for example, but not limited to, a credit-linked note).", "label": "Disclosure of Credit Derivatives [Table Text Block]", "terseLabel": "Credit Derivatives Sold (Table)" } } }, "localname": "DisclosureOfCreditDerivativesTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_DividendIncomeOperating": { "auth_ref": [ "r678" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of operating dividend income on securities.", "label": "Dividend Income, Operating", "verboseLabel": "Dividend income" } } }, "localname": "DividendIncomeOperating", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_DividendsCommonStock": { "auth_ref": [ "r354", "r682" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).", "label": "Dividends, Common Stock", "negatedLabel": "Dividends to common stockholders" } } }, "localname": "DividendsCommonStock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_DividendsCommonStockAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Dividends, Common Stock [Abstract]", "verboseLabel": "Common Stock Dividends" } } }, "localname": "DividendsCommonStockAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_DividendsDeclaredTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of information related to dividends declared, including paid and unpaid dividends.", "label": "Dividends Declared [Table Text Block]", "terseLabel": "Common Stock Dividends (Table)" } } }, "localname": "DividendsDeclaredTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_DomesticCountryMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Designated tax department of the government that is entitled to levy and collect income taxes from the entity in its country of domicile.", "label": "Domestic Country [Member]", "terseLabel": "U.S. Federal" } } }, "localname": "DomesticCountryMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "domainItemType" }, "us-gaap_DueFromAffiliates": { "auth_ref": [ "r139", "r647", "r648", "r649", "r724" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 7.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.", "label": "Due from Affiliates", "verboseLabel": "Amounts receivable from subsidiaries" } } }, "localname": "DueFromAffiliates", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EarningsPerShareAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Earnings Per Common Share", "terseLabel": "Earnings per common share" } } }, "localname": "EarningsPerShareAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "stringItemType" }, "us-gaap_EarningsPerShareBasic": { "auth_ref": [ "r86", "r147", "r156", "r158", "r159", "r160", "r164", "r676", "r730" ], "lang": { "en-US": { "role": { "documentation": "The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.", "label": "Earnings Per Share, Basic", "terseLabel": "Basic earnings per common share (in dollars per share)", "verboseLabel": "Basic" } } }, "localname": "EarningsPerShareBasic", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "perShareItemType" }, "us-gaap_EarningsPerShareBasicAndDilutedAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Earnings Per Share, Basic and Diluted [Abstract]", "terseLabel": "Net income (loss) per common share:" } } }, "localname": "EarningsPerShareBasicAndDilutedAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "stringItemType" }, "us-gaap_EarningsPerShareDiluted": { "auth_ref": [ "r86", "r147", "r156", "r158", "r159", "r160", "r164", "r676", "r730" ], "lang": { "en-US": { "role": { "documentation": "The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.", "label": "Earnings Per Share, Diluted", "terseLabel": "Diluted earnings per common share (in dollars per share)", "verboseLabel": "Diluted" } } }, "localname": "EarningsPerShareDiluted", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "perShareItemType" }, "us-gaap_EarningsPerSharePolicyTextBlock": { "auth_ref": [ "r128", "r161", "r162", "r163" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.", "label": "Earnings Per Share, Policy [Policy Text Block]", "terseLabel": "Earnings Per Common Share - Policy" } } }, "localname": "EarningsPerSharePolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_EarningsPerShareTextBlock": { "auth_ref": [ "r165" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for earnings per share.", "label": "Earnings Per Share [Text Block]", "terseLabel": "Earnings Per Common Share" } } }, "localname": "EarningsPerShareTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShare" ], "xbrltype": "textBlockItemType" }, "us-gaap_EffectiveIncomeTaxRateContinuingOperations": { "auth_ref": [ "r137", "r465", "r466" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en-US": { "role": { "documentation": "Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.", "label": "Effective Income Tax Rate Reconciliation, Percent", "totalLabel": "Effective income tax rate (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateContinuingOperations", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Effective Income Tax Rate Reconciliation, Percent [Abstract]", "terseLabel": "Reconciliation between the U.S. corporate income tax rate and the effective income tax rate from continuing operations" } } }, "localname": "EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "stringItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 1.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of domestic federal statutory tax rate applicable to pretax income (loss).", "label": "Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent", "terseLabel": "U.S. corporate income tax rate (as a percent)", "verboseLabel": "U.S. statutory tax rate (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails", "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 2.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the income tax rates.", "label": "Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent", "negatedLabel": "Impact of the Tax Cuts and Jobs Act (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsDividends": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 3.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": -1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for dividend.", "label": "Effective Income Tax Rate Reconciliation, Deduction, Dividend, Percent", "negatedLabel": "Dividends received deduction (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationDeductionsDividends", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationEquityInEarningsLossesOfUnconsolidatedSubsidiary": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 4.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": -1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to equity in earnings (loss) of unconsolidated subsidiaries exempt from income taxes.", "label": "Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Percent", "negatedLabel": "Impact of equity method presentation (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationEquityInEarningsLossesOfUnconsolidatedSubsidiary", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 9.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.", "label": "Effective Income Tax Rate Reconciliation, Other Adjustments, Percent", "terseLabel": "Other income tax rate impacts (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationOtherAdjustments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 7.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).", "label": "Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent", "terseLabel": "State income taxes (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 5.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": -1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.", "label": "Effective Income Tax Rate Reconciliation, Tax Credit, Percent", "negatedLabel": "Tax credits (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationTaxCredits", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome": { "auth_ref": [ "r465", "r466", "r495" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails": { "order": 6.0, "parentTag": "us-gaap_EffectiveIncomeTaxRateContinuingOperations", "weight": -1.0 } }, "lang": { "en-US": { "role": { "documentation": "Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income (loss) exempt from income taxes.", "label": "Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent", "negatedLabel": "Interest exclusion from taxable income (as a percent)" } } }, "localname": "EffectiveIncomeTaxRateReconciliationTaxExemptIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesEffectiveIncomeTaxRateDetails" ], "xbrltype": "percentItemType" }, "us-gaap_EmbeddedDerivativeFinancialInstrumentsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Derivative instrument embedded in host contract.", "label": "Embedded Derivative Financial Instruments [Member]", "terseLabel": "Embedded derivative financial instruments" } } }, "localname": "EmbeddedDerivativeFinancialInstrumentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_EmbeddedDerivativeLiabilityMeasurementInput": { "auth_ref": [ "r591" ], "lang": { "en-US": { "role": { "documentation": "Value of input used to measure embedded derivative liability.", "label": "Embedded Derivative Liability, Measurement Input", "terseLabel": "Embedded derivative, Input" } } }, "localname": "EmbeddedDerivativeLiabilityMeasurementInput", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "decimalItemType" }, "us-gaap_EmbeddedDerivativeLiabilityValuationTechniqueExtensibleList": { "auth_ref": [ "r590" ], "lang": { "en-US": { "role": { "documentation": "Indicates valuation technique for measuring embedded derivative liability.", "label": "Embedded Derivative Liability, Valuation Technique [Extensible List]", "terseLabel": "Embedded derivative, Valuation technique" } } }, "localname": "EmbeddedDerivativeLiabilityValuationTechniqueExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized": { "auth_ref": [ "r451" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cost not yet recognized for nonvested award under share-based payment arrangement.", "label": "Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized", "terseLabel": "Unrecognized compensation costs" } } }, "localname": "EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1": { "auth_ref": [ "r451" ], "lang": { "en-US": { "role": { "documentation": "Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.", "label": "Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition", "terseLabel": "Weighted-average service period over which unrecognized compensation costs will be recognized" } } }, "localname": "EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "durationItemType" }, "us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense": { "auth_ref": [ "r450" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of tax benefit for recognition of expense of award under share-based payment arrangement.", "label": "Employee Service Share-based Compensation, Tax Benefit from Compensation Expense", "terseLabel": "Related income tax benefit" } } }, "localname": "EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions": { "auth_ref": [ "r453" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of tax benefit from exercise of option under share-based payment arrangement.", "label": "Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options", "terseLabel": "Tax benefits realized for the tax deductions from options exercised" } } }, "localname": "EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EmployeeStockOptionMember": { "auth_ref": [ "r448" ], "lang": { "en-US": { "role": { "documentation": "Share-based payment arrangement granting right, subject to vesting and other restrictions, to purchase or sell certain number of shares at predetermined price for specified period of time.", "label": "Employee Stock Option [Member]", "terseLabel": "Nonqualified Stock Options" } } }, "localname": "EmployeeStockOptionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares": { "auth_ref": [ "r455" ], "lang": { "en-US": { "role": { "documentation": "The shares or units in an ESOP trust that have been assigned to individual participant accounts based on a known formula. IRS rules require allocations to be nondiscriminatory generally based on compensation, length of service, or a combination of both. For any particular participant such shares or units may be vested, unvested, or partially vested.", "label": "Employee Stock Ownership Plan (ESOP), Number of Allocated Shares", "terseLabel": "Number of common stock shares allocated participants in the employee stock ownership plan" } } }, "localname": "EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_EquityComponentDomain": { "auth_ref": [ "r347" ], "lang": { "en-US": { "role": { "documentation": "Components of equity are the parts of the total Equity balance including that which is allocated to common, preferred, treasury stock, retained earnings, etc.", "label": "Equity Component [Domain]", "terseLabel": "Equity Component [Domain]" } } }, "localname": "EquityComponentDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_EquityContractMember": { "auth_ref": [ "r385", "r557" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to share prices.", "label": "Equity Contract [Member]", "terseLabel": "Equity contracts" } } }, "localname": "EquityContractMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Equity Method Investment, Summarized Financial Information [Abstract]", "terseLabel": "Summarized financial information of unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets": { "auth_ref": [ "r7", "r130", "r247", "r251", "r608" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of assets reported by an equity method investment of the entity.", "label": "Equity Method Investment, Summarized Financial Information, Assets", "terseLabel": "Total assets, unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity": { "auth_ref": [ "r7", "r141", "r251", "r608", "r609" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of equity, including noncontrolling interest, reported by an equity method investment of the entity.", "label": "Equity Method Investment Summarized Financial Information, Equity", "totalLabel": "Total equity, unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationEquity", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities": { "auth_ref": [ "r7", "r130", "r247", "r251", "r608" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of liabilities reported by an equity method investment of the entity.", "label": "Equity Method Investment, Summarized Financial Information, Liabilities", "terseLabel": "Total liabilities, unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss": { "auth_ref": [ "r7", "r130", "r247", "r251", "r608" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of net income (loss) reported by an equity method investment of the entity.", "label": "Equity Method Investment, Summarized Financial Information, Net Income (Loss)", "terseLabel": "Net income, unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue": { "auth_ref": [ "r7", "r251" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of revenue from sale of product and rendering of service reported by equity method investee.", "label": "Equity Method Investment, Summarized Financial Information, Revenue", "terseLabel": "Total revenues, unconsolidated entities" } } }, "localname": "EquityMethodInvestmentSummarizedFinancialInformationRevenue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentUnderlyingEquityInNetAssets": { "auth_ref": [ "r249" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This item represents the entity's ownership percentage in the investee multiplied by the investee's total equity.", "label": "Equity Method Investment, Underlying Equity in Net Assets", "terseLabel": "Net investment in unconsolidated entities" } } }, "localname": "EquityMethodInvestmentUnderlyingEquityInNetAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsOtherInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestments": { "auth_ref": [ "r35", "r182", "r245" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 7.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 9.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.", "label": "Equity Method Investments", "terseLabel": "Investment in unconsolidated entities" } } }, "localname": "EquityMethodInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquityMethodInvestmentsMember": { "auth_ref": [ "r244" ], "lang": { "en-US": { "role": { "documentation": "Investment in the stock of an investee which is adjusted for the investor's share of the earnings or losses of the investee after the date of acquisition.", "label": "Equity Method Investments [Member]", "terseLabel": "Real Estate Ventures" } } }, "localname": "EquityMethodInvestmentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_EquitySecuritiesFvNi": { "auth_ref": [ "r603" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 3.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 3.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 3.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).", "label": "Equity Securities, FV-NI", "terseLabel": "Equity securities", "verboseLabel": "Equity securities (2019 and 2018 include $810.9 million and $774.8 million related to consolidated variable interest entities)" } } }, "localname": "EquitySecuritiesFvNi", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquitySecuritiesFvNiGainLoss": { "auth_ref": [ "r243" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 8.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).", "label": "Equity Securities, FV-NI, Gain (Loss)", "terseLabel": "Equity securities" } } }, "localname": "EquitySecuritiesFvNiGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss": { "auth_ref": [ "r243" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).", "label": "Equity Securities, FV-NI, Unrealized Gain (Loss)", "terseLabel": "Unrealized gains (losses) on equity securities" } } }, "localname": "EquitySecuritiesFvNiUnrealizedGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_EquitySecuritiesMember": { "auth_ref": [ "r12", "r18", "r242", "r667", "r693", "r833" ], "lang": { "en-US": { "role": { "documentation": "Ownership interest or right to acquire or dispose of ownership interest in corporations and other legal entities for which ownership interest is represented by shares of common or preferred stock, convertible securities, stock rights, or stock warrants.", "label": "Equity Securities [Member]", "terseLabel": "Equity securities" } } }, "localname": "EquitySecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_EstimateOfFairValueFairValueDisclosureMember": { "auth_ref": [ "r605" ], "lang": { "en-US": { "role": { "documentation": "Measured as an estimate of fair value.", "label": "Estimate Of Fair Value Fair Value Disclosure [Member]", "terseLabel": "Assets (liabilities) measured at fair value" } } }, "localname": "EstimateOfFairValueFairValueDisclosureMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ExcessOfReportedClosedBlockLiabilitiesOverAssetsDesignatedToClosedBlock": { "auth_ref": [ "r806", "r818" ], "calculation": { "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails": { "order": 1.0, "parentTag": "us-gaap_ClosedBlockAssetsAndLiabilitiesMaximumFutureEarningsToBeRecognized", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The difference between the liabilities of and the assets allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block.", "label": "Excess of Reported Closed Block Liabilities over Assets Designated to Closed Block", "totalLabel": "Excess of Closed Block liabilities over assets designated to the Closed Block" } } }, "localname": "ExcessOfReportedClosedBlockLiabilitiesOverAssetsDesignatedToClosedBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockAssetsAndLiabilitiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]", "verboseLabel": "Assets (liabilities) measured at fair value on a recurring basis" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable": { "auth_ref": [ "r586", "r587", "r588", "r599" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about asset and liability measured at fair value on recurring and nonrecurring basis.", "label": "Fair Value Measurements, Recurring and Nonrecurring [Table]" } } }, "localname": "FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain": { "auth_ref": [ "r592" ], "lang": { "en-US": { "role": { "documentation": "Class of asset.", "label": "Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain]", "terseLabel": "Asset Class [Domain]" } } }, "localname": "FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueByAssetClassAxis": { "auth_ref": [ "r586", "r599" ], "lang": { "en-US": { "role": { "documentation": "Information by class of asset.", "label": "Asset Class [Axis]" } } }, "localname": "FairValueByAssetClassAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueByFairValueHierarchyLevelAxis": { "auth_ref": [ "r385", "r386", "r418", "r587", "r650" ], "lang": { "en-US": { "role": { "documentation": "Information by level within fair value hierarchy and fair value measured at net asset value per share as practical expedient.", "label": "Fair Value, Hierarchy [Axis]" } } }, "localname": "FairValueByFairValueHierarchyLevelAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueByLiabilityClassAxis": { "auth_ref": [ "r597", "r599" ], "lang": { "en-US": { "role": { "documentation": "Information by class of liability.", "label": "Liability Class [Axis]" } } }, "localname": "FairValueByLiabilityClassAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueByMeasurementBasisAxis": { "auth_ref": [ "r586", "r600" ], "lang": { "en-US": { "role": { "documentation": "Information by measurement basis.", "label": "Measurement Basis [Axis]" } } }, "localname": "FairValueByMeasurementBasisAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueByMeasurementFrequencyAxis": { "auth_ref": [ "r586", "r587", "r590", "r591", "r602" ], "lang": { "en-US": { "role": { "documentation": "Information by measurement frequency.", "label": "Measurement Frequency [Axis]" } } }, "localname": "FairValueByMeasurementFrequencyAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Fair Value Measurements" } } }, "localname": "FairValueDisclosuresAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_FairValueDisclosuresTextBlock": { "auth_ref": [ "r597" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.", "label": "Fair Value Disclosures [Text Block]", "terseLabel": "Fair Value Measurements" } } }, "localname": "FairValueDisclosuresTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurements" ], "xbrltype": "textBlockItemType" }, "us-gaap_FairValueHedgingMember": { "auth_ref": [ "r539" ], "lang": { "en-US": { "role": { "documentation": "A hedge of the exposure to changes in the fair value of a recognized asset or liability, or of an unrecognized firm commitment, that are attributable to a particular risk.", "label": "Fair Value Hedging [Member]", "terseLabel": "Fair Value Hedges" } } }, "localname": "FairValueHedgingMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueInputsLevel1Member": { "auth_ref": [ "r385", "r386", "r418", "r587", "r651" ], "lang": { "en-US": { "role": { "documentation": "Quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date.", "label": "Fair Value Inputs Level1 [Member]", "terseLabel": "Fair value hierarchy Level 1" } } }, "localname": "FairValueInputsLevel1Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueInputsLevel2Member": { "auth_ref": [ "r385", "r386", "r418", "r587", "r652" ], "lang": { "en-US": { "role": { "documentation": "Inputs other than quoted prices included within level 1 that are observable for an asset or liability, either directly or indirectly, including, but not limited to, quoted prices for similar assets or liabilities in active markets, or quoted prices for identical or similar assets or liabilities in inactive markets.", "label": "Fair Value Inputs Level2 [Member]", "terseLabel": "Fair value hierarchy Level 2" } } }, "localname": "FairValueInputsLevel2Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueInputsLevel3Member": { "auth_ref": [ "r385", "r386", "r418", "r587", "r653" ], "lang": { "en-US": { "role": { "documentation": "Unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value Inputs Level3 [Member]", "terseLabel": "Fair value hierarchy Level 3" } } }, "localname": "FairValueInputsLevel3Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments": { "auth_ref": [ "r601" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).", "label": "Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments", "terseLabel": "Unfunded commitments of investments measured using NAV" } } }, "localname": "FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain": { "auth_ref": [ "r592" ], "lang": { "en-US": { "role": { "documentation": "Represents classes of liabilities measured and disclosed at fair value.", "label": "Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Liability Class [Domain]", "terseLabel": "Fair Value by Liability Class [Domain]" } } }, "localname": "FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember": { "auth_ref": [ "r386", "r585", "r602" ], "lang": { "en-US": { "role": { "documentation": "Fair value measured at net asset value per share as practical expedient.", "label": "Fair Value Measured At Net Asset Value Per Share [Member]", "terseLabel": "Amount measured at net asset value" } } }, "localname": "FairValueMeasuredAtNetAssetValuePerShareMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueMeasurementFrequencyDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement frequency.", "label": "Fair Value Measurement Frequency [Domain]", "terseLabel": "Fair Value, Measurement Frequency [Domain]" } } }, "localname": "FairValueMeasurementFrequencyDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1": { "auth_ref": [ "r593" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings", "terseLabel": "Total realized/unrealized gains (losses) included in net income, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss": { "auth_ref": [ "r594" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)", "terseLabel": "Total realized/unrealized gains (losses) included in other comprehensive income, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 3.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances", "terseLabel": "Issuances, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 2.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases", "terseLabel": "Purchases, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements)", "terseLabel": "Net purchases, sales, issuances and settlements, assets", "totalLabel": "Net purchases, sales, issuances and settlements, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 1.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales", "negatedLabel": "Sales, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 4.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements", "negatedLabel": "Settlements, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3": { "auth_ref": [ "r596" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3", "terseLabel": "Transfers into Level 3, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3": { "auth_ref": [ "r596" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3", "negatedLabel": "Transfers out of Level 3, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue": { "auth_ref": [ "r592" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value", "periodEndLabel": "Ending balance, assets", "periodStartLabel": "Beginning balance, assets" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings": { "auth_ref": [ "r593" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings", "terseLabel": "Total realized/unrealized gains (losses) included in net income, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome": { "auth_ref": [ "r594" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3).", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)", "terseLabel": "Total realized/unrealized gains (losses) included in other comprehensive income, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchasesSalesIssuancesSettlements": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases, (Sales), Issuances, (Settlements)", "negatedLabel": "Net purchases, sales, issuances and settlements, liabilities", "negatedTotalLabel": "Net purchases, sales, issuances and settlements, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchasesSalesIssuancesSettlements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements": { "auth_ref": [ "r595" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 2.0, "parentTag": "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchasesSalesIssuancesSettlements", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements", "terseLabel": "Settlements, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue": { "auth_ref": [ "r592" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value", "negatedPeriodEndLabel": "Ending balance, liabilities", "negatedPeriodStartLabel": "Beginning balance, liabilities" } } }, "localname": "FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueMeasurementsFairValueHierarchyDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Categories used to prioritize the inputs to valuation techniques to measure fair value.", "label": "Fair Value Measurements Fair Value Hierarchy [Domain]", "terseLabel": "Fair Value Plan Asset Measurement [Domain]" } } }, "localname": "FairValueMeasurementsFairValueHierarchyDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueMeasurementsRecurringMember": { "auth_ref": [ "r597", "r602" ], "lang": { "en-US": { "role": { "documentation": "Frequent fair value measurement. Includes, but is not limited to, fair value adjustment for impairment of asset, liability or equity, frequently measured at fair value.", "label": "Fair Value Measurements Recurring [Member]", "terseLabel": "Recurring Fair Value Measurements" } } }, "localname": "FairValueMeasurementsRecurringMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FairValueNetAssetLiability": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of asset after deduction of liability.", "label": "Fair Value, Net Asset (Liability)", "totalLabel": "Net assets" } } }, "localname": "FairValueNetAssetLiability", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings": { "auth_ref": [ "r593", "r598" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of gain (loss) recognized in income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3).", "label": "Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings", "terseLabel": "Total realized/unrealized gains (losses) included in net income, net derivative assets" } } }, "localname": "FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases": { "auth_ref": [ "r595", "r598" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 1.0, "parentTag": "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases", "terseLabel": "Purchases, net derivative assets (liabilities)" } } }, "localname": "FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchases", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements": { "auth_ref": [ "r598" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases, Sales, Issues, Settlements", "terseLabel": "Net purchases, sales, issuances and settlements, net derivative assets", "totalLabel": "Net purchases, sales, issuances and settlements, net derivative assets (liabilities)" } } }, "localname": "FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales": { "auth_ref": [ "r595", "r598" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails": { "order": 2.0, "parentTag": "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of sales of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Sales", "negatedLabel": "Sales, net derivative assets (liabilities)" } } }, "localname": "FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSales", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs": { "auth_ref": [ "r586", "r598" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.", "label": "Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs", "periodEndLabel": "Ending balance, net derivative assets", "periodStartLabel": "Beginning balance, net derivative assets" } } }, "localname": "FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueOptionChangesInFairValueGainLoss1": { "auth_ref": [ "r610" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.", "label": "Fair Value, Option, Changes in Fair Value, Gain (Loss)", "verboseLabel": "Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected" } } }, "localname": "FairValueOptionChangesInFairValueGainLoss1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FairValueOptionQuantitativeDisclosuresLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Fair Value, Option, Quantitative Disclosures [Line Items]", "terseLabel": "Fair Value Option, Quantitative Disclosures" } } }, "localname": "FairValueOptionQuantitativeDisclosuresLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueOptionQuantitativeDisclosuresTable": { "auth_ref": [ "r611", "r612", "r613" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about asset and liability measured at fair value under fair value option.", "label": "Fair Value, Option, Quantitative Disclosures [Table]" } } }, "localname": "FairValueOptionQuantitativeDisclosuresTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FairValueOptionQuantitativeDisclosuresTextBlock": { "auth_ref": [ "r609", "r611", "r612", "r613" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of information about asset and liability measured at fair value under fair value option.", "label": "Fair Value, Option, Quantitative Disclosures [Table Text Block]", "terseLabel": "Fair Value Option (Table)" } } }, "localname": "FairValueOptionQuantitativeDisclosuresTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable": { "auth_ref": [ "r544", "r549", "r575" ], "lang": { "en-US": { "role": { "documentation": "Schedule that discloses the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position.", "label": "Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]", "terseLabel": "Schedule of Fair Values of Derivative Instruments by Derivative Contract Type [Table]" } } }, "localname": "FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinanceLeaseInterestExpense": { "auth_ref": [ "r635", "r638", "r646" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "us-gaap_LeaseCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of interest expense on finance lease liability.", "label": "Finance Lease, Interest Expense", "terseLabel": "Interest on lease liabilities" } } }, "localname": "FinanceLeaseInterestExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilitiesPaymentsRollingMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Finance Lease Liabilities, Payments, Rolling Maturity [Abstract]", "terseLabel": "Finance leases, payments due for the twelve months ending December 31:" } } }, "localname": "FinanceLeaseLiabilitiesPaymentsRollingMaturityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinanceLeaseLiability": { "auth_ref": [ "r633", "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_TotalLeaseLiabilities", "weight": 1.0 }, "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 2.0, "parentTag": "us-gaap_FinanceLeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Present value of lessee's discounted obligation for lease payments from finance lease.", "label": "Finance Lease, Liability", "terseLabel": "Finance lease liabilities", "verboseLabel": "Present value of lease liabilities" } } }, "localname": "FinanceLeaseLiability", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDue": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease.", "label": "Finance Lease, Liability, Payments, Due", "totalLabel": "Total lease payments" } } }, "localname": "FinanceLeaseLiabilityPaymentsDue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInNextRollingTwelveMonths", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due after fifth fiscal year following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Next Rolling Twelve Months", "terseLabel": "2020" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingAfterYearFive", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due after fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Rolling after Year Five", "terseLabel": "2025 and thereafter" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFive": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearFive", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Rolling Year Five", "terseLabel": "2024" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInRollingYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFour": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearFour", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fourth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Rolling Year Four", "terseLabel": "2023" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInRollingYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearThree": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearThree", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due in third rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Rolling Year Three", "terseLabel": "2022" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInRollingYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearTwo": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearTwo", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for finance lease, due in second rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Finance Lease, Liability, Payments, Due in Rolling Year Two", "terseLabel": "2021" } } }, "localname": "FinanceLeaseLiabilityPaymentsDueInRollingYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList": { "auth_ref": [ "r634" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of financial position that includes finance lease liability.", "label": "Finance Lease, Liability, Statement of Financial Position [Extensible List]" } } }, "localname": "FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityUndiscountedExcessAmount", "weight": 1.0 }, "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 1.0, "parentTag": "us-gaap_FinanceLeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.", "label": "Finance Lease, Liability, Undiscounted Excess Amount", "terseLabel": "Less: interest" } } }, "localname": "FinanceLeaseLiabilityUndiscountedExcessAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeasePrincipalPayments": { "auth_ref": [ "r636", "r641" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash outflow for principal payment on finance lease.", "label": "Finance Lease, Principal Payments", "terseLabel": "Payments for finance leases" } } }, "localname": "FinanceLeasePrincipalPayments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseRightOfUseAsset": { "auth_ref": [ "r632" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_TotalLeaseRightOfUseAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's right to use underlying asset under finance lease.", "label": "Finance Lease, Right-of-Use Asset", "terseLabel": "Finance lease assets" } } }, "localname": "FinanceLeaseRightOfUseAsset", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseRightOfUseAssetAmortization": { "auth_ref": [ "r635", "r638", "r646" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "us-gaap_LeaseCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense attributable to right-of-use asset from finance lease.", "label": "Finance Lease, Right-of-Use Asset, Amortization", "terseLabel": "Amortization of right-of-use assets" } } }, "localname": "FinanceLeaseRightOfUseAssetAmortization", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList": { "auth_ref": [ "r634" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of financial position that includes finance lease right-of-use asset.", "label": "Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]" } } }, "localname": "FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent": { "auth_ref": [ "r643", "r646" ], "lang": { "en-US": { "role": { "documentation": "Weighted average discount rate for finance lease calculated at point in time.", "label": "Finance Lease, Weighted Average Discount Rate, Percent", "terseLabel": "Weighted-average discount rate, Finance leases" } } }, "localname": "FinanceLeaseWeightedAverageDiscountRatePercent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1": { "auth_ref": [ "r642", "r646" ], "lang": { "en-US": { "role": { "documentation": "Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.", "label": "Finance Lease, Weighted Average Remaining Lease Term", "terseLabel": "Weighted average remaining lease term, Finance leases" } } }, "localname": "FinanceLeaseWeightedAverageRemainingLeaseTerm1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "durationItemType" }, "us-gaap_FinancialInstrumentAxis": { "auth_ref": [ "r255", "r260", "r261", "r264", "r266", "r275", "r277", "r278", "r279" ], "lang": { "en-US": { "role": { "documentation": "Information by type of financial instrument.", "label": "Financial Instrument [Axis]" } } }, "localname": "FinancialInstrumentAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancialInstrumentPerformanceStatusAxis": { "auth_ref": [ "r266" ], "lang": { "en-US": { "role": { "documentation": "Information by category of performance or non-performance status of financial instruments.", "label": "Financial Instrument Performance Status [Axis]" } } }, "localname": "FinancialInstrumentPerformanceStatusAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancialInstrumentPerformanceStatusDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Category of performance or non-performance status of financial instruments, including but not limited to, financing receivables, loans, debt, and investments.", "label": "Financial Instrument Performance Status [Domain]", "terseLabel": "Financial Instrument Performance Status [Domain]" } } }, "localname": "FinancialInstrumentPerformanceStatusDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]", "terseLabel": "Assets (liabilities)" } } }, "localname": "FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Financial Instruments Owned and Pledged as Collateral [Abstract]", "terseLabel": "Securities Posted as Collateral" } } }, "localname": "FinancialInstrumentsOwnedAndPledgedAsCollateralAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsSecuritiesPostedAsCollateralDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty": { "auth_ref": [ "r654" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions where counterparty has the right to re-pledge such.", "label": "Financial Instruments Owned and Pledged as Collateral, Amount Eligible to be Repledged by Counterparty", "terseLabel": "Securities posted as collateral eligible to be sold or repledged" } } }, "localname": "FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsSecuritiesPostedAsCollateralDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancialServiceOtherMember": { "auth_ref": [ "r362" ], "lang": { "en-US": { "role": { "documentation": "Financial assistance, including, but not limited to, management and maintenance of depositor account, credit card, merchant discount, trust, investment and insurance, classified as other.", "label": "Financial Service Other [Member]", "terseLabel": "Other fee revenue" } } }, "localname": "FinancialServiceOtherMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLosses": { "auth_ref": [ "r194", "r252", "r256", "r259", "r668" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails": { "order": 2.0, "parentTag": "us-gaap_NotesReceivableNet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.", "label": "Financing Receivable, Allowance for Credit Losses", "negatedLabel": "Mortgage loan valuation allowance", "periodEndLabel": "Ending balance, Mortgage loan valuation allowance", "periodStartLabel": "Beginning balance, Mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment": { "auth_ref": [ "r200" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": 1.0, "parentTag": "us-gaap_FinancingReceivableAllowanceForCreditLosses", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.", "label": "Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment", "terseLabel": "Collectively evaluated for impairment, Mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1": { "auth_ref": [ "r200" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": 2.0, "parentTag": "us-gaap_FinancingReceivableAllowanceForCreditLosses", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.", "label": "Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment", "terseLabel": "Individually evaluated for impairment, Mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Financing Receivable, Allowance for Credit Losses [Line Items]", "terseLabel": "Mortgage loan valuation allowance disclosures" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery": { "auth_ref": [ "r197", "r258", "r268", "r668" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of recovery of financing receivables doubtful of collection that were previously charged off.", "label": "Financing Receivable, Allowance for Credit Losses, Recovery", "terseLabel": "Recoveries: Mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesRecovery", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Financing Receivable, Allowance for Credit Losses [Roll Forward]", "terseLabel": "Changes in mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs": { "auth_ref": [ "r196", "r257", "r268", "r668" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of writeoff of financing receivable, charged against allowance for credit loss.", "label": "Financing Receivable, Allowance for Credit Losses, Write-downs", "negatedLabel": "Charge-offs: Mortgage loan valuation allowance" } } }, "localname": "FinancingReceivableAllowanceForCreditLossesWriteOffs", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment": { "auth_ref": [ "r201" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": 2.0, "parentTag": "us-gaap_NotesReceivableGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The balance of financing receivables that were collectively evaluated for impairment.", "label": "Financing Receivable, Collectively Evaluated for Impairment", "terseLabel": "Collectively evaluated for impairment, Mortgage loans" } } }, "localname": "FinancingReceivableCollectivelyEvaluatedForImpairment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableImpairedLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Financing Receivable, Impaired [Line Items]", "terseLabel": "Impaired mortgage loans" } } }, "localname": "FinancingReceivableImpairedLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment": { "auth_ref": [ "r201" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": 1.0, "parentTag": "us-gaap_NotesReceivableGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The balance of financing receivables that were individually evaluated for impairment.", "label": "Financing Receivable, Individually Evaluated for Impairment", "terseLabel": "Individually evaluated for impairment, Mortgage loans" } } }, "localname": "FinancingReceivableIndividuallyEvaluatedForImpairment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing": { "auth_ref": [ "r213", "r263", "r269" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of financing receivable 90 days or more past due and still accruing.", "label": "Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing", "terseLabel": "Recorded investment 90 days or more past due and accruing" } } }, "localname": "FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableRecordedInvestmentCurrent": { "auth_ref": [ "r261", "r269" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails": { "order": 1.0, "parentTag": "us-gaap_NotesReceivableGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of financing receivable not past due.", "label": "Financing Receivable, Recorded Investment, Current", "terseLabel": "Current" } } }, "localname": "FinancingReceivableRecordedInvestmentCurrent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableRecordedInvestmentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Financing Receivable, Recorded Investment [Line Items]", "terseLabel": "Mortgage loan credit quality disclosures" } } }, "localname": "FinancingReceivableRecordedInvestmentLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus": { "auth_ref": [ "r212", "r262" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of financing receivable on nonaccrual status.", "label": "Financing Receivable, Recorded Investment, Nonaccrual Status", "terseLabel": "Mortgage loans, Non-accrual status" } } }, "localname": "FinancingReceivableRecordedInvestmentNonaccrualStatus", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableRecordedInvestmentPastDue": { "auth_ref": [ "r215", "r261", "r269" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails": { "order": 2.0, "parentTag": "us-gaap_NotesReceivableGross", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of financing receivable past due.", "label": "Financing Receivable, Recorded Investment, Past Due", "terseLabel": "Past due" } } }, "localname": "FinancingReceivableRecordedInvestmentPastDue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Financing Receivable, Recorded Investment, Past Due [Line Items]", "terseLabel": "Mortgage loan non-accrual and aging disclosures" } } }, "localname": "FinancingReceivableRecordedInvestmentPastDueLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivableSignificantPurchases": { "auth_ref": [ "r198", "r253" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase from purchase of financing receivable.", "label": "Financing Receivable, Significant Purchases", "terseLabel": "Mortgage loans, purchased" } } }, "localname": "FinancingReceivableSignificantPurchases", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivableSignificantSales": { "auth_ref": [ "r199", "r254" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of decrease from sale and reclassification to held-for-sale of financing receivable.", "label": "Financing Receivable, Significant Sales", "terseLabel": "Mortgage loans, sold" } } }, "localname": "FinancingReceivableSignificantSales", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinancingReceivables30To59DaysPastDueMember": { "auth_ref": [ "r269" ], "lang": { "en-US": { "role": { "documentation": "Financial asset more than 29 days past due but fewer than 60 days past due.", "label": "Financing Receivables30 To59 Days Past Due [Member]", "terseLabel": "30 to 59 Days Past Due" } } }, "localname": "FinancingReceivables30To59DaysPastDueMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancingReceivables60To89DaysPastDueMember": { "auth_ref": [ "r269" ], "lang": { "en-US": { "role": { "documentation": "Financial asset more than 59 days past due but fewer than 90 days past due.", "label": "Financing Receivables60 To89 Days Past Due [Member]", "terseLabel": "60 to 89 Days Past Due" } } }, "localname": "FinancingReceivables60To89DaysPastDueMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember": { "auth_ref": [ "r269" ], "lang": { "en-US": { "role": { "documentation": "Financial asset equal to or greater than 90 days past due.", "label": "Financing Receivables Equal To Greater Than90 Days Past Due [Member]", "terseLabel": "90 Days or More Past Due" } } }, "localname": "FinancingReceivablesEqualToGreaterThan90DaysPastDueMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FinancingReceivablesPeriodPastDueAxis": { "auth_ref": [ "r261", "r269" ], "lang": { "en-US": { "role": { "documentation": "Information by time period financial asset is past due.", "label": "Financing Receivables, Period Past Due [Axis]" } } }, "localname": "FinancingReceivablesPeriodPastDueAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FinancingReceivablesPeriodPastDueDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Period in which financial asset is past due. Element name and standard label in Financial Asset, [numeric lower end] to [numeric higher end] [date measure] Past Due [Member] or Financial Asset, Greater Than [low end numeric value] [date measure] Past Due [Member] or Financial Asset, Less Than [high end numeric value] [date measure] Past Due [Member] formats.", "label": "Financing Receivables Period Past Due [Domain]", "terseLabel": "Financing Receivables, Period Past Due [Domain]" } } }, "localname": "FinancingReceivablesPeriodPastDueDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FiniteLivedIntangibleAssetUsefulLife": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Finite-Lived Intangible Asset, Useful Life", "terseLabel": "Finite lived intangible asset, useful life" } } }, "localname": "FiniteLivedIntangibleAssetUsefulLife", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "durationItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization": { "auth_ref": [ "r300" ], "calculation": { "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails": { "order": 2.0, "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.", "label": "Finite-Lived Intangible Assets, Accumulated Amortization", "terseLabel": "Accumulated amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAccumulatedAmortization", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths": { "auth_ref": [ "r302" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months", "terseLabel": "Year 1: Finite lived intangible assets amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive": { "auth_ref": [ "r302" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Five", "terseLabel": "Year 5: Finite lived intangible assets amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour": { "auth_ref": [ "r302" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Four", "terseLabel": "Year 4: Finite lived intangible assets amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree": { "auth_ref": [ "r302" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Three", "terseLabel": "Year 3: Finite lived intangible assets amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo": { "auth_ref": [ "r302" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Two", "terseLabel": "Year 2: Finite lived intangible assets amortization" } } }, "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis": { "auth_ref": [ "r294", "r296", "r300", "r304", "r656" ], "lang": { "en-US": { "role": { "documentation": "Information by major type or class of finite-lived intangible assets.", "label": "Finite-Lived Intangible Assets by Major Class [Axis]" } } }, "localname": "FiniteLivedIntangibleAssetsByMajorClassAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]", "terseLabel": "Estimated amortization expense for the next five years" } } }, "localname": "FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_FiniteLivedIntangibleAssetsGross": { "auth_ref": [ "r300", "r656" ], "calculation": { "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails": { "order": 1.0, "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.", "label": "Finite-Lived Intangible Assets, Gross", "terseLabel": "Gross carrying amount" } } }, "localname": "FiniteLivedIntangibleAssetsGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain": { "auth_ref": [ "r294", "r299" ], "lang": { "en-US": { "role": { "documentation": "The major class of finite-lived intangible asset (for example, patents, trademarks, copyrights, etc.) A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.", "label": "Finite Lived Intangible Assets Major Class Name [Domain]", "terseLabel": "Finite-Lived Intangible Assets, Major Class Name [Domain]" } } }, "localname": "FiniteLivedIntangibleAssetsMajorClassNameDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FiniteLivedIntangibleAssetsNet": { "auth_ref": [ "r300" ], "calculation": { "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.", "label": "Finite-Lived Intangible Assets, Net", "totalLabel": "Net carrying amount" } } }, "localname": "FiniteLivedIntangibleAssetsNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsFiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FinitelivedIntangibleAssetsAcquired1": { "auth_ref": [ "r295" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.", "label": "Finite-lived Intangible Assets Acquired", "terseLabel": "Finite lived intangible assets acquired" } } }, "localname": "FinitelivedIntangibleAssetsAcquired1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_FirstMortgageMember": { "auth_ref": [ "r835" ], "lang": { "en-US": { "role": { "documentation": "Loan secured by real property that has a first (highest) lien on such property in the event of default by the borrower.", "label": "First Mortgage [Member]", "terseLabel": "First liens" } } }, "localname": "FirstMortgageMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FixedIncomeFundsMember": { "auth_ref": [ "r385" ], "lang": { "en-US": { "role": { "documentation": "Investment that pools funds from investors to invest in a combination of underlying investments, primarily fixed income investments.", "label": "Fixed Income Funds [Member]", "terseLabel": "Fixed income investment funds" } } }, "localname": "FixedIncomeFundsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_FixedIncomeSecuritiesMember": { "auth_ref": [ "r385", "r418" ], "lang": { "en-US": { "role": { "documentation": "Investment that provides a return in the form of fixed periodic payments and eventual return of principal at maturity.", "label": "Fixed Income Securities [Member]", "terseLabel": "Fixed income security portfolios" } } }, "localname": "FixedIncomeSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ForeignCountryMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Designated tax departments of governments entitled to levy and collect income taxes from the entity outside the entity's country of domicile.", "label": "Foreign Country [Member]", "terseLabel": "Foreign" } } }, "localname": "ForeignCountryMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock": { "auth_ref": [ "r128", "r615", "r618" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for (1) transactions denominated in a currency other than the reporting enterprise's functional currency, (2) translating foreign currency financial statements that are incorporated into the financial statements of the reporting enterprise by consolidation, combination, or the equity method of accounting, and (3) remeasurement of the financial statements of a foreign reporting enterprise in a hyperinflationary economy.", "label": "Foreign Currency Transactions and Translations Policy [Policy Text Block]", "terseLabel": "Foreign Exchange - Policy" } } }, "localname": "ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_ForeignExchangeContractMember": { "auth_ref": [ "r385", "r556" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to foreign exchange rates.", "label": "Foreign Exchange Contract [Member]", "terseLabel": "Foreign exchange contracts" } } }, "localname": "ForeignExchangeContractMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ForeignExchangeForwardMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Foreign exchange forward traded on an exchange (examples include but are not limited to the International Securities Exchange, Philadelphia Stock Exchange, or the Chicago Mercantile Exchange) for options or future contracts to buy or sell a certain currency, at a specified date, at a fixed exercise exchange rate.", "label": "Foreign Exchange Forward [Member]", "terseLabel": "Currency forwards" } } }, "localname": "ForeignExchangeForwardMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ForeignExchangeOptionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "An option that allows the holder to buy (if call) or sell (if put) an underlying currency at a fixed exercise rate, expressed as an exchange, during a specified period (an American option) or at a specified date (a European option).", "label": "Foreign Exchange Option [Member]", "terseLabel": "Currency options" } } }, "localname": "ForeignExchangeOptionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ForeignGovernmentDebtSecuritiesMember": { "auth_ref": [ "r385", "r799" ], "lang": { "en-US": { "role": { "documentation": "Debt security issued by government not domiciled in United States of America (US).", "label": "Foreign Government Debt Securities [Member]", "terseLabel": "Non-U.S. governments" } } }, "localname": "ForeignGovernmentDebtSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_GainLossOnDerivativeInstrumentsNetPretax": { "auth_ref": [ "r545" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.", "label": "Gain (Loss) on Derivative Instruments, Net, Pretax", "totalLabel": "Total gain (loss) recognized for hedging relationships" } } }, "localname": "GainLossOnDerivativeInstrumentsNetPretax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet": { "auth_ref": [ "r583" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 8.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.", "label": "Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net", "verboseLabel": "Gain (loss) reclassified from AOCI into net income as a result that a forecasted transaction is no longer probable of occurring" } } }, "localname": "GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GainLossOnInvestments": { "auth_ref": [ "r91", "r118", "r221" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 4.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 }, "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 4.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 }, "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 3.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": -1.0 }, "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails": { "order": 1.0, "parentTag": "pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 2.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of realized and unrealized gain (loss) on investment.", "label": "Gain (Loss) on Investments", "negatedLabel": "Net realized capital (gains) losses", "negatedTerseLabel": "Net realized capital (gains) losses", "terseLabel": "Net realized capital gains (losses)", "totalLabel": "Net realized capital gains (losses)" } } }, "localname": "GainLossOnInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationNetRealizedCapitalGainsLossesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_Goodwill": { "auth_ref": [ "r284", "r285" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 14.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 7.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.", "label": "Goodwill", "periodEndLabel": "Ending balance, Goodwill", "periodStartLabel": "Beginning balance, Goodwill", "terseLabel": "Goodwill" } } }, "localname": "Goodwill", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_GoodwillAcquiredDuringPeriod": { "auth_ref": [ "r286" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.", "label": "Goodwill, Acquired During Period", "terseLabel": "Goodwill from acquisitions" } } }, "localname": "GoodwillAcquiredDuringPeriod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Goodwill and Other Intangible Assets" } } }, "localname": "GoodwillAndIntangibleAssetsDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock": { "auth_ref": [ "r306" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for goodwill and intangible assets.", "label": "Goodwill and Intangible Assets Disclosure [Text Block]", "terseLabel": "Goodwill and Other Intangible Assets" } } }, "localname": "GoodwillAndIntangibleAssetsDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssets" ], "xbrltype": "textBlockItemType" }, "us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock": { "auth_ref": [ "r128", "r290", "r297" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for goodwill and intangible assets. This accounting policy also may address how an entity assesses and measures impairment of goodwill and intangible assets.", "label": "Goodwill and Intangible Assets, Policy [Policy Text Block]", "terseLabel": "Goodwill and Other Intangibles - Policy" } } }, "localname": "GoodwillAndIntangibleAssetsPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_GoodwillForeignCurrencyTranslationGainLoss": { "auth_ref": [ "r288" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.", "label": "Goodwill, Translation Adjustments", "terseLabel": "Foreign currency, Goodwill" } } }, "localname": "GoodwillForeignCurrencyTranslationGainLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GoodwillLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Goodwill [Line Items]", "terseLabel": "Goodwill [Line Items]" } } }, "localname": "GoodwillLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "stringItemType" }, "us-gaap_GoodwillOtherIncreaseDecrease": { "auth_ref": [ "r289" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease), classified as other, of an asset representing the future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.", "label": "Goodwill, Other Changes", "terseLabel": "Other, Goodwill" } } }, "localname": "GoodwillOtherIncreaseDecrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GoodwillRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Goodwill [Roll Forward]", "terseLabel": "Changes in Goodwill" } } }, "localname": "GoodwillRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "stringItemType" }, "us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit": { "auth_ref": [ "r287" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.", "label": "Goodwill, Written off Related to Sale of Business Unit", "negatedLabel": "Goodwill disposed" } } }, "localname": "GoodwillWrittenOffRelatedToSaleOfBusinessUnit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GuaranteeObligationsByNatureAxis": { "auth_ref": [ "r329" ], "lang": { "en-US": { "role": { "documentation": "Information by nature of guarantee.", "label": "Guarantor Obligations, Nature [Axis]" } } }, "localname": "GuaranteeObligationsByNatureAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_GuaranteeObligationsMaximumExposure": { "auth_ref": [ "r328" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.", "label": "Guarantor Obligations, Maximum Exposure, Undiscounted", "terseLabel": "Maximum exposure under guarantees" } } }, "localname": "GuaranteeObligationsMaximumExposure", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GuaranteeObligationsNatureDomain": { "auth_ref": [ "r326" ], "lang": { "en-US": { "role": { "documentation": "Represents a description of the nature of the guarantee or each group of similar guarantees.", "label": "Guarantee Obligations Nature [Domain]", "terseLabel": "Guarantor Obligations, Nature [Domain]" } } }, "localname": "GuaranteeObligationsNatureDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_GuaranteedInterestContracts": { "auth_ref": [ "r698", "r700" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails": { "order": 2.0, "parentTag": "us-gaap_DepositContractsLiabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of the liability as of the balance sheet date pertaining to the guarantee given by the insurance entity to contract holders of a specified rate of return (a guaranteed yield) on their investments for a specified period.", "label": "Guaranteed Interest Contracts", "terseLabel": "GICs" } } }, "localname": "GuaranteedInterestContracts", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesComponentsOfContractholderFundsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_GuaranteesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Guarantees [Abstract]", "terseLabel": "Guarantees and Indemnifications" } } }, "localname": "GuaranteesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_HedgeFundsMember": { "auth_ref": [ "r385" ], "lang": { "en-US": { "role": { "documentation": "Investments in registered hedge funds.", "label": "Hedge Funds [Member]", "terseLabel": "Hedge funds" } } }, "localname": "HedgeFundsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_HedgedAssetDiscontinuedFairValueHedgeCumulativeIncreaseDecrease": { "auth_ref": [ "r564" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": 1.0, "parentTag": "pfg_HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk, remaining after discontinued hedge.", "label": "Hedged Asset, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)", "terseLabel": "Cumulative amount of fair value hedging basis adjustment - Discontinued hedging relationships" } } }, "localname": "HedgedAssetDiscontinuedFairValueHedgeCumulativeIncreaseDecrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_HedgedAssetFairValueHedge": { "auth_ref": [ "r562" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": 2.0, "parentTag": "pfg_HedgedAssetFairValueHedgeIncludingDiscontinued", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset hedged in fair value hedging relationship.", "label": "Hedged Asset, Fair Value Hedge", "terseLabel": "Amortized cost of hedged item - Active hedging relationships" } } }, "localname": "HedgedAssetFairValueHedge", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease": { "auth_ref": [ "r563" ], "calculation": { "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails": { "order": 2.0, "parentTag": "pfg_HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.", "label": "Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)", "terseLabel": "Cumulative amount of fair value hedging basis adjustment - Active hedging relationships" } } }, "localname": "HedgedAssetFairValueHedgeCumulativeIncreaseDecrease", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_HedgingDesignationAxis": { "auth_ref": [ "r542", "r561" ], "lang": { "en-US": { "role": { "documentation": "Information by designation of purpose of derivative instrument.", "label": "Hedging Designation [Axis]" } } }, "localname": "HedgingDesignationAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_HedgingDesignationDomain": { "auth_ref": [ "r542" ], "lang": { "en-US": { "role": { "documentation": "Designation of purpose of derivative instrument.", "label": "Hedging Designation [Domain]", "terseLabel": "Hedging Designation [Domain]" } } }, "localname": "HedgingDesignationDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_HedgingRelationshipDomain": { "auth_ref": [ "r542" ], "lang": { "en-US": { "role": { "documentation": "Nature or intent of a hedge.", "label": "Hedging Relationship [Domain]", "terseLabel": "Hedging Relationship [Domain]" } } }, "localname": "HedgingRelationshipDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_HomeEquityMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Revolving, open-end loan extended under a line of credit and secured by the borrower's residential property.", "label": "Home Equity [Member]", "terseLabel": "Home equity" } } }, "localname": "HomeEquityMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment": { "auth_ref": [ "r206", "r209" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.", "label": "Impaired Financing Receivable, Average Recorded Investment", "totalLabel": "Average investment in impaired mortgage loans" } } }, "localname": "ImpairedFinancingReceivableAverageRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod": { "auth_ref": [ "r207" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.", "label": "Impaired Financing Receivable, Interest Income, Accrual Method", "totalLabel": "Interest income recognized on impaired mortgage loans" } } }, "localname": "ImpairedFinancingReceivableInterestIncomeAccrualMethod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableRecordedInvestment": { "auth_ref": [ "r203" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.", "label": "Impaired Financing Receivable, Recorded Investment", "totalLabel": "Recorded investment in impaired mortgage loans" } } }, "localname": "ImpairedFinancingReceivableRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableRelatedAllowance": { "auth_ref": [ "r204" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of allowance for credit losses related to recorded investment.", "label": "Impaired Financing Receivable, Related Allowance", "terseLabel": "Related allowance for impaired mortgage loans" } } }, "localname": "ImpairedFinancingReceivableRelatedAllowance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance": { "auth_ref": [ "r205" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.", "label": "Impaired Financing Receivable, Unpaid Principal Balance", "totalLabel": "Unpaid principal balance of impaired mortgage loans" } } }, "localname": "ImpairedFinancingReceivableUnpaidPrincipalBalance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment": { "auth_ref": [ "r206", "r209" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 1.0, "parentTag": "us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.", "label": "Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment", "terseLabel": "Average investment in impaired mortgage loans with no related allowance" } } }, "localname": "ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment": { "auth_ref": [ "r203" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 1.0, "parentTag": "us-gaap_ImpairedFinancingReceivableRecordedInvestment", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.", "label": "Impaired Financing Receivable, with No Related Allowance, Recorded Investment", "terseLabel": "Recorded investment in impaired mortgage loans with no related allowance" } } }, "localname": "ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance": { "auth_ref": [ "r205" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 1.0, "parentTag": "us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.", "label": "Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance", "terseLabel": "Unpaid principal balance of impaired mortgage loans with no related allowance" } } }, "localname": "ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment": { "auth_ref": [ "r206", "r209" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 2.0, "parentTag": "us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.", "label": "Impaired Financing Receivable, with Related Allowance, Average Recorded Investment", "terseLabel": "Average investment in impaired mortgage loans with related allowance" } } }, "localname": "ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod": { "auth_ref": [ "r207" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 1.0, "parentTag": "us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.", "label": "Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method", "terseLabel": "Interest income recognized on impaired mortgage loans with related allowance" } } }, "localname": "ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment": { "auth_ref": [ "r203" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 2.0, "parentTag": "us-gaap_ImpairedFinancingReceivableRecordedInvestment", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.", "label": "Impaired Financing Receivable, with Related Allowance, Recorded Investment", "terseLabel": "Recorded investment in impaired mortgage loans with related allowance" } } }, "localname": "ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance": { "auth_ref": [ "r205" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails": { "order": 2.0, "parentTag": "us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.", "label": "Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance", "terseLabel": "Unpaid principal balance of impaired mortgage loans with related allowance" } } }, "localname": "ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ImpairedFinancingReceivablesTableTextBlock": { "auth_ref": [ "r208" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of impaired financing receivables.", "label": "Impaired Financing Receivables [Table Text Block]", "terseLabel": "Impaired Mortgage Loans (Table)" } } }, "localname": "ImpairedFinancingReceivablesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic": { "auth_ref": [ "r136" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 1.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.", "label": "Income (Loss) from Continuing Operations before Income Taxes, Domestic", "terseLabel": "Income (loss) before income taxes - domestic" } } }, "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest [Abstract]", "terseLabel": "Income (loss) before income taxes" } } }, "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign": { "auth_ref": [ "r136" ], "calculation": { "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": 2.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.", "label": "Income (Loss) from Continuing Operations before Income Taxes, Foreign", "terseLabel": "Income (loss) before income taxes - foreign" } } }, "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax": { "auth_ref": [ "r0", "r1", "r2", "r3", "r4", "r6", "r86", "r728" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.", "label": "Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest", "terseLabel": "Income (loss) from discontinued operations, net of related income taxes" } } }, "localname": "IncomeLossFromDiscontinuedOperationsNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeLossFromEquityMethodInvestments": { "auth_ref": [ "r84", "r118", "r179", "r245", "r674", "r727" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_ProfitLoss", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 2.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": -1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_NetIncomeLoss", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of income (loss) for proportionate share of equity method investee's income (loss).", "label": "Income (Loss) from Equity Method Investments", "negatedLabel": "Equity in the net (income) loss of subsidiaries", "terseLabel": "Equity in the net income (loss) of subsidiaries" } } }, "localname": "IncomeLossFromEquityMethodInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions": { "auth_ref": [ "r118" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 6.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "This element represents the undistributed income (or loss) of equity method investments, net of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations; such investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.", "label": "Income (Loss) from Equity Method Investments, Net of Dividends or Distributions", "negatedTerseLabel": "(Income) loss from equity method investments, net of dividends received" } } }, "localname": "IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeStatementAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Consolidated Statements of Operations" } } }, "localname": "IncomeStatementAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_IncomeStatementLocationAxis": { "auth_ref": [ "r309" ], "lang": { "en-US": { "role": { "documentation": "Information by location in the income statement.", "label": "Income Statement Location [Axis]" } } }, "localname": "IncomeStatementLocationAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "stringItemType" }, "us-gaap_IncomeStatementLocationDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Location in the income statement.", "label": "Income Statement Location [Domain]", "terseLabel": "Income Statement Location [Domain]" } } }, "localname": "IncomeStatementLocationDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "domainItemType" }, "us-gaap_IncomeTaxAuthorityAxis": { "auth_ref": [ "r469" ], "lang": { "en-US": { "role": { "documentation": "Information by tax jurisdiction.", "label": "Income Tax Authority [Axis]" } } }, "localname": "IncomeTaxAuthorityAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "stringItemType" }, "us-gaap_IncomeTaxAuthorityDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Agency, division or body classification that levies income taxes, examines tax returns for compliance, or grants exemptions from or makes other decisions pertaining to income taxes.", "label": "Income Tax Authority [Domain]", "terseLabel": "Income Tax Authority [Domain]" } } }, "localname": "IncomeTaxAuthorityDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "domainItemType" }, "us-gaap_IncomeTaxDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Income Taxes" } } }, "localname": "IncomeTaxDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_IncomeTaxDisclosureTextBlock": { "auth_ref": [ "r503" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.", "label": "Income Tax Disclosure [Text Block]", "terseLabel": "Income Taxes" } } }, "localname": "IncomeTaxDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxes" ], "xbrltype": "textBlockItemType" }, "us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority": { "auth_ref": [ "r471" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.", "label": "Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority", "terseLabel": "Current income tax (receivables) payables associated with outstanding audit issues" } } }, "localname": "IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeTaxExpenseBenefit": { "auth_ref": [ "r131", "r180", "r500" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_ProfitLoss", "weight": -1.0 }, "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_NetIncomeLoss", "weight": -1.0 }, "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.", "label": "Income Tax Expense (Benefit)", "totalLabel": "Income taxes (benefits)", "verboseLabel": "Income taxes (benefits)" } } }, "localname": "IncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureIncomeTaxesIncomeTaxExpenseAndIncomeBeforeIncomeTaxesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeTaxPolicyTextBlock": { "auth_ref": [ "r79", "r128", "r462", "r463", "r478", "r479", "r485", "r502", "r836" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.", "label": "Income Tax, Policy [Policy Text Block]", "terseLabel": "Income Taxes - Policy" } } }, "localname": "IncomeTaxPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_IncomeTaxReceivable": { "auth_ref": [ "r33", "r689" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 5.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.", "label": "Income Taxes Receivable", "terseLabel": "Income taxes receivable" } } }, "localname": "IncomeTaxReceivable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncomeTaxesPaidNet": { "auth_ref": [ "r123" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.", "label": "Income Taxes Paid, Net", "terseLabel": "Cash paid for (received from) income taxes" } } }, "localname": "IncomeTaxesPaidNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInAccruedInvestmentIncomeReceivable": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 7.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The increase (decrease) during the reporting period in investment income that has been earned but not yet received in cash.", "label": "Increase (Decrease) in Accrued Investment Income Receivable", "negatedLabel": "Accrued investment income" } } }, "localname": "IncreaseDecreaseInAccruedInvestmentIncomeReceivable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInDeferredIncomeTaxes": { "auth_ref": [ "r117" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa.", "label": "Increase (Decrease) in Deferred Income Taxes", "negatedLabel": "Cumulative effect adjustment, decrease to deferred income taxes" } } }, "localname": "IncreaseDecreaseInDeferredIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInDeposits": { "auth_ref": [ "r121", "r680" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 14.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The net cash inflow or outflow for the increase (decrease) in the beginning and end of period deposits balances.", "label": "Increase (Decrease) in Deposits", "terseLabel": "Net increase (decrease) in banking operation deposits", "verboseLabel": "Net increase (decrease) in banking operation deposits" } } }, "localname": "IncreaseDecreaseInDeposits", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInIncomeTaxes": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 4.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 11.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The increase (decrease) during the reporting period in the amounts payable to taxing authorities for taxes that are based on the reporting entity's earnings, net of amounts receivable from taxing authorities for refunds of overpayments or recoveries of income taxes, and in deferred and other tax liabilities and assets.", "label": "Increase (Decrease) in Income Taxes", "terseLabel": "Current and deferred income taxes (benefits)" } } }, "localname": "IncreaseDecreaseInIncomeTaxes", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInInsuranceLiabilities": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 10.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The increase (decrease) in insurance liability balances during the period.", "label": "Increase (Decrease) in Insurance Liabilities", "terseLabel": "Contractholder and policyholder liabilities and dividends" } } }, "localname": "IncreaseDecreaseInInsuranceLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInOperatingCapitalAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Increase (Decrease) in Operating Capital [Abstract]", "terseLabel": "Changes in:" } } }, "localname": "IncreaseDecreaseInOperatingCapitalAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 14.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase (decrease) in operating assets after deduction of operating liabilities classified as other.", "label": "Increase (Decrease) in Other Operating Assets and Liabilities, Net", "negatedLabel": "Other assets and liabilities" } } }, "localname": "IncreaseDecreaseInOtherOperatingCapitalNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInReceivables": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 9.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The increase (decrease) during the reporting period in the total amount due within one year (or one operating cycle) from all parties, associated with underlying transactions that are classified as operating activities.", "label": "Increase (Decrease) in Receivables", "negatedLabel": "Premiums due and other receivables" } } }, "localname": "IncreaseDecreaseInReceivables", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_IncreaseDecreaseInStockholdersEquityRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Increase (Decrease) in Stockholders' Equity [Roll Forward]", "terseLabel": "Increase (decrease) in stockholders' equity" } } }, "localname": "IncreaseDecreaseInStockholdersEquityRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "stringItemType" }, "us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements": { "auth_ref": [ "r157", "r162" ], "calculation": { "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": 2.0, "parentTag": "us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.", "label": "Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements", "terseLabel": "Stock-based compensation awards" } } }, "localname": "IncrementalCommonSharesAttributableToShareBasedPaymentArrangements", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Indefinite-lived Intangible Assets [Line Items]", "terseLabel": "Indefinite Lived Intangible Assets" } } }, "localname": "IndefiniteLivedIntangibleAssetsByMajorClassLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill": { "auth_ref": [ "r303" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.", "label": "Indefinite-Lived Intangible Assets (Excluding Goodwill)", "terseLabel": "Net carrying amount of unamortized indefinite lived intangible assets" } } }, "localname": "IndefiniteLivedIntangibleAssetsExcludingGoodwill", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_IndustrialMiscellaneousAndAllOthersMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents investments by the reporting entity in equity securities issued by any type of company other than public utilities, banks, trusts, and insurance companies the investments in which are summarized elsewhere.", "label": "Industrial Miscellaneous And All Others [Member]", "terseLabel": "Common stocks: Industrial, miscellaneous and all other" } } }, "localname": "IndustrialMiscellaneousAndAllOthersMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_IntangibleAssetsNetExcludingGoodwill": { "auth_ref": [ "r292", "r298" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 15.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 8.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.", "label": "Intangible Assets, Net (Excluding Goodwill)", "terseLabel": "Other intangibles" } } }, "localname": "IntangibleAssetsNetExcludingGoodwill", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_InterestExpense": { "auth_ref": [ "r82", "r178", "r619", "r622", "r679" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of the cost of borrowed funds accounted for as interest expense.", "label": "Interest Expense", "terseLabel": "Interest expense" } } }, "localname": "InterestExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_InterestIncomeOperating": { "auth_ref": [ "r88" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.", "label": "Interest Income, Operating", "verboseLabel": "Interest income" } } }, "localname": "InterestIncomeOperating", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_InterestPaidNet": { "auth_ref": [ "r110", "r114", "r123" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.", "label": "Interest Paid, Net", "terseLabel": "Cash paid for interest" } } }, "localname": "InterestPaidNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_InterestPayableCurrentAndNoncurrent": { "auth_ref": [ "r670", "r722" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 2.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of interest payable on debt, including, but not limited to, trade payables.", "label": "Interest Payable", "terseLabel": "Accrued investment payable" } } }, "localname": "InterestPayableCurrentAndNoncurrent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_InterestRateContractMember": { "auth_ref": [ "r385", "r555" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument whose primary underlying risk is tied to the right to receive or pay a sum of money at a given interest rate.", "label": "Interest Rate Contract [Member]", "terseLabel": "Interest rate contracts" } } }, "localname": "InterestRateContractMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_InterestRateSwapMember": { "auth_ref": [ "r555" ], "lang": { "en-US": { "role": { "documentation": "Forward based contracts in which two parties agree to swap periodic payments that are fixed at the outset of the swap contract with variable payments based on a market interest rate (index rate) over a specified period.", "label": "Interest Rate Swap [Member]", "terseLabel": "Interest rate swaps" } } }, "localname": "InterestRateSwapMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_InternalReplacementsOfInsuranceContractsPolicy": { "auth_ref": [ "r128", "r751" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for previously deferred policy acquisition costs and previously deferred sales inducements when internal replacements of insurance contracts occur, including whether or not the entity has availed itself of the alternative guidance permitted under GAAP, and, if so, for which types of internal replacement transactions.", "label": "Internal Replacements of Insurance Contracts, Policy [Policy Text Block]", "terseLabel": "Deferred Acquisition Costs on Internal Replacements - Policy" } } }, "localname": "InternalReplacementsOfInsuranceContractsPolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_InvestmentIncomeInvestmentExpense": { "auth_ref": [ "r93", "r734" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails": { "order": 2.0, "parentTag": "us-gaap_NetInvestmentIncome", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of expenses related to the generation of investment income.", "label": "Investment Income, Investment Expense", "negatedLabel": "Investment expenses" } } }, "localname": "InvestmentIncomeInvestmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_InvestmentIncomeTextBlock": { "auth_ref": [ "r90", "r92", "r93", "r734" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of investment income, including, but not limited to, interest and dividend income and amortization of discount (premium) derived from debt and equity securities. Excludes realized and unrealized gain (loss) on investments.", "label": "Investment Income [Table Text Block]", "terseLabel": "Net Investment Income (Table)" } } }, "localname": "InvestmentIncomeTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_InvestmentPolicyTextBlock": { "auth_ref": [ "r248" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for investment in financial asset.", "label": "Investment, Policy [Policy Text Block]", "terseLabel": "Investments - Policy" } } }, "localname": "InvestmentPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_InvestmentSecondaryCategorizationAxis": { "auth_ref": [ "r824", "r825", "r826", "r827" ], "lang": { "en-US": { "role": { "documentation": "Information by second categorization of investments, which may include, but is not limited to industry.", "label": "Investment Secondary Categorization [Axis]" } } }, "localname": "InvestmentSecondaryCategorizationAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_InvestmentTypeAxis": { "auth_ref": [ "r821", "r823", "r828", "r829" ], "lang": { "en-US": { "role": { "documentation": "Information by type of investments.", "label": "Investment Type [Axis]" } } }, "localname": "InvestmentTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/DisclosureInvestmentsRealEstateDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_InvestmentTypeCategorizationMember": { "auth_ref": [ "r821", "r823", "r828", "r829" ], "lang": { "en-US": { "role": { "documentation": "Asset obtained to generate income or appreciate in value.", "label": "Investment Type Categorization [Member]", "terseLabel": "Investments [Domain]" } } }, "localname": "InvestmentTypeCategorizationMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/DisclosureInvestmentsRealEstateDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_Investments": { "auth_ref": [ "r718" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Sum of the carrying amounts as of the balance sheet date of all investments.", "label": "Investments.", "totalLabel": "Total investments" } } }, "localname": "Investments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_InvestmentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Investments [Abstract]", "terseLabel": "Investments" } } }, "localname": "InvestmentsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesCashAndCashEquivalentsInvestmentsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_InvestmentsBySecondaryCategorizationDomain": { "auth_ref": [ "r822", "r826" ], "lang": { "en-US": { "role": { "documentation": "Investments in the \"Investment Holdings [Table]\" and the \"Summary of Investment Holdings [Table]\" are often categorized at two levels. The first categorization is the investment type. The second categorization can vary. The usual secondary categorizations are industry, country or geography.", "label": "Investments By Secondary Categorization [Domain]", "terseLabel": "Investments by Secondary Categorization [Domain]" } } }, "localname": "InvestmentsBySecondaryCategorizationDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_JuniorSubordinatedDebtMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Borrowing that has a lower priority than senior instruments in event of liquidation of the entity's assets.", "label": "Junior Subordinated Debt [Member]", "terseLabel": "Junior subordinated notes" } } }, "localname": "JuniorSubordinatedDebtMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_LeaseCost": { "auth_ref": [ "r644", "r646" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of lease cost recognized by lessee for lease contract.", "label": "Lease, Cost", "totalLabel": "Total lease cost" } } }, "localname": "LeaseCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LeaseCostAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Lease, Cost [Abstract]", "terseLabel": "Lease cost" } } }, "localname": "LeaseCostAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LeaseCostTableTextBlock": { "auth_ref": [ "r644" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of lessee's lease cost. Includes, but is not limited to, interest expense for finance lease, amortization of right-of-use asset for finance lease, operating lease cost, short-term lease cost, variable lease cost and sublease income.", "label": "Lease, Cost [Table Text Block]", "terseLabel": "Lease Cost (Table)" } } }, "localname": "LeaseCostTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_LeasePracticalExpedientUseOfHindsight": { "auth_ref": [ "r629", "r630" ], "lang": { "en-US": { "role": { "documentation": "Indicates (true false) whether practical expedient is elected to use hindsight in determining lease term and in assessing impairment of right-of-use asset.", "label": "Lease, Practical Expedient, Use of Hindsight [true false]", "terseLabel": "Hindsight practical expedient to determine the lease term for existing leases" } } }, "localname": "LeasePracticalExpedientUseOfHindsight", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "booleanItemType" }, "us-gaap_LeasePracticalExpedientsPackage": { "auth_ref": [ "r628", "r630" ], "lang": { "en-US": { "role": { "documentation": "Indicates (true false) whether practical expedients are elected for not reassessing whether any expired or existing contract is or contains lease, lease classification for expired or existing lease, and initial direct cost for any existing lease.", "label": "Lease, Practical Expedients, Package [true false]", "terseLabel": "Package of practical expedients permitted under transition guidance" } } }, "localname": "LeasePracticalExpedientsPackage", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "booleanItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 1.0, "parentTag": "pfg_LeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease.", "label": "Lessee, Operating Lease, Liability, Payments, Due", "totalLabel": "Total lease payments" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingAfterYearFive", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due after fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five", "terseLabel": "2025 and thereafter" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearFive", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five", "terseLabel": "2024" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearFour", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Four", "terseLabel": "2023" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearThree", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three", "terseLabel": "2022" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInRollingYearTwo", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two", "terseLabel": "2021" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityPaymentsDueInNextRollingTwelveMonths", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in next rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.", "label": "Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months", "terseLabel": "2020" } } }, "localname": "LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount": { "auth_ref": [ "r645" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_LeaseLiabilityUndiscountedExcessAmount", "weight": 1.0 }, "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 1.0, "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.", "label": "Lessee, Operating Lease, Liability, Undiscounted Excess Amount", "terseLabel": "Less: interest" } } }, "localname": "LesseeOperatingLeaseLiabilityUndiscountedExcessAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_Liabilities": { "auth_ref": [ "r41" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 1.0, "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.", "label": "Liabilities", "terseLabel": "Total liabilities", "totalLabel": "Total liabilities" } } }, "localname": "Liabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Liabilities [Abstract]", "terseLabel": "Liabilities" } } }, "localname": "LiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "stringItemType" }, "us-gaap_LiabilitiesAndStockholdersEquity": { "auth_ref": [ "r32", "r665", "r709" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.", "label": "Liabilities and Equity", "totalLabel": "Total liabilities and stockholders' equity" } } }, "localname": "LiabilitiesAndStockholdersEquity", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilitiesFairValueDisclosure": { "auth_ref": [ "r586" ], "calculation": { "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 2.0, "parentTag": "us-gaap_FairValueNetAssetLiability", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Fair value of financial and nonfinancial obligations.", "label": "Financial and Nonfinancial Liabilities, Fair Value Disclosure", "negatedLabel": "Liabilities measured at fair value", "negatedTotalLabel": "Total liabilities" } } }, "localname": "LiabilitiesFairValueDisclosure", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense": { "auth_ref": [ "r754", "r757" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 1.0, "parentTag": "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet", "weight": 1.0 }, "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.", "label": "Liability for Claims and Claims Adjustment Expense", "periodEndLabel": "Balance at end of period, unpaid claims", "periodStartLabel": "Balance at beginning of period, unpaid claims", "totalLabel": "Liability for unpaid claims" } } }, "localname": "LiabilityForClaimsAndClaimsAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForFuturePolicyBenefitByProductSegmentLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Liability for Future Policy Benefit, by Product Segment [Line Items]" } } }, "localname": "LiabilityForFuturePolicyBenefitByProductSegmentLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LiabilityForFuturePolicyBenefitByProductSegmentTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Reflects the carrying amount of and other relevant, pertinent information about the liability as of the balance sheet date for future benefits to be paid to or on behalf of policyholders and related expenses less the present value of future net premiums by major product line segment.", "label": "Liability for Future Policy Benefit, by Product Segment [Table]" } } }, "localname": "LiabilityForFuturePolicyBenefitByProductSegmentTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LiabilityForFuturePolicyBenefitsAndUnpaidClaimsAndClaimsAdjustmentExpense": { "auth_ref": [ "r697", "r754", "r757" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The aggregate amount of policy reserves (provided for future obligations including unpaid claims and claims adjustment expenses) and policy benefits (liability for future policy benefits) as of the balance sheet date; grouped amount of all the liabilities associated with the company's insurance policies.", "label": "Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense", "terseLabel": "Future policy benefits and claims" } } }, "localname": "LiabilityForFuturePolicyBenefitsAndUnpaidClaimsAndClaimsAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]", "terseLabel": "Payments:" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1": { "auth_ref": [ "r756" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 1.0, "parentTag": "us-gaap_PaymentsForLossesAndLossAdjustmentExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of payments to settle claims incurred in the current period and related claims settlement costs.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year", "terseLabel": "Payments: Current year" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1": { "auth_ref": [ "r756" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 2.0, "parentTag": "us-gaap_PaymentsForLossesAndLossAdjustmentExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of payments to settle claims incurred in prior periods and related claims settlement costs.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years", "terseLabel": "Payments: Prior years" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1": { "auth_ref": [ "r755" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims", "totalLabel": "Total incurred" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]", "terseLabel": "Incurred:" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet": { "auth_ref": [ "r690", "r754", "r757" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Net", "periodEndLabel": "Net balance at end of period, unpaid claims", "periodStartLabel": "Net balance at beginning of period, unpaid claims" } } }, "localname": "LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LifeAndAnnuityInsuranceProductLineMember": { "auth_ref": [ "r776" ], "lang": { "en-US": { "role": { "documentation": "Contract providing periodic payment upon death of insured.", "label": "Life And Annuity Insurance Product Line [Member]", "terseLabel": "Life insurance and annuities" } } }, "localname": "LifeAndAnnuityInsuranceProductLineMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "domainItemType" }, "us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity": { "auth_ref": [ "r39" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.", "label": "Line of Credit Facility, Maximum Borrowing Capacity", "terseLabel": "Credit facilities" } } }, "localname": "LineOfCreditFacilityMaximumBorrowingCapacity", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LoansAssumed1": { "auth_ref": [ "r124", "r125", "r126" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The fair value of loans assumed in noncash investing or financing activities.", "label": "Loans Assumed", "terseLabel": "Long-term debt assumed on real estate properties received" } } }, "localname": "LoansAssumed1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_LoansInsurancePolicy": { "auth_ref": [ "r672", "r715" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 6.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 6.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before allowance of loans made to policy and contract holders using their life insurance contracts' cash value or separate accounts as collateral. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums over and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.", "label": "Loans, Gross, Insurance Policy", "terseLabel": "Policy loans" } } }, "localname": "LoansInsurancePolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_LoansPledgedAsCollateral": { "auth_ref": [ "r211", "r654" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.", "label": "Loans Pledged as Collateral", "terseLabel": "Commercial mortgage loans and residential first lien mortgages posted as collateral associated with obligation under funding agreements with the Federal Home Loan Bank of Des Moines" } } }, "localname": "LoansPledgedAsCollateral", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsSecuritiesPostedAsCollateralDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebt": { "auth_ref": [ "r20", "r335", "r663", "r704" ], "calculation": { "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 1.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 5.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.", "label": "Long-term Debt.", "negatedLabel": "Long-term debt", "terseLabel": "Long-term debt", "totalLabel": "Long-term debt carrying amount", "verboseLabel": "Long-term debt (2019 and 2018 include $64.2 million and $58.4 million related to consolidated variable interest entities)" } } }, "localname": "LongTermDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureDebtComponentsOfLongTermDebtDetails", "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtByMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Long-term Debt, Fiscal Year Maturity [Abstract]", "terseLabel": "Future maturities of long-term debt" } } }, "localname": "LongTermDebtByMaturityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 6.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal after Year Five", "terseLabel": "Year 6 and thereafter: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 1.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months", "terseLabel": "Year 1: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 5.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal in Year Five", "terseLabel": "Year 5: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 4.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal in Year Four", "terseLabel": "Year 4: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 3.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal in Year Three", "terseLabel": "Year 3: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo": { "auth_ref": [ "r144", "r331" ], "calculation": { "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails": { "order": 2.0, "parentTag": "us-gaap_LongTermDebt", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.", "label": "Long-term Debt, Maturities, Repayments of Principal in Year Two", "terseLabel": "Year 2: Long-term debt maturities" } } }, "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtFutureMaturitiesOfLongTermDebtDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LongTermDebtNoncurrentAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Long-term Debt, Excluding Current Maturities [Abstract]", "terseLabel": "Long-Term Debt" } } }, "localname": "LongTermDebtNoncurrentAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LongtermDebtTypeAxis": { "auth_ref": [ "r44" ], "lang": { "en-US": { "role": { "documentation": "Information by type of long-term debt.", "label": "Long-term Debt, Type [Axis]" } } }, "localname": "LongtermDebtTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LongtermDebtTypeDomain": { "auth_ref": [ "r44", "r332" ], "lang": { "en-US": { "role": { "documentation": "Type of long-term debt arrangement, such as notes, line of credit, commercial paper, asset-based financing, project financing, letter of credit financing. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer.", "label": "Longterm Debt Type [Domain]", "terseLabel": "Long-term Debt, Type [Domain]" } } }, "localname": "LongtermDebtTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_LossContingenciesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Loss Contingencies [Line Items]" } } }, "localname": "LossContingenciesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LossContingenciesTable": { "auth_ref": [ "r315", "r316", "r317", "r319", "r320", "r321", "r323", "r324", "r325" ], "lang": { "en-US": { "role": { "documentation": "Discloses the specific components (such as the nature, name, and date) of the loss contingency and gives an estimate of the possible loss or range of loss, or states that a reasonable estimate cannot be made. Excludes environmental contingencies, warranties and unconditional purchase obligations.", "label": "Loss Contingencies [Table]" } } }, "localname": "LossContingenciesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LossContingencyAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Loss Contingency [Abstract]", "terseLabel": "Loss contingencies - disclosures" } } }, "localname": "LossContingencyAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_LossContingencyAccrualInsuranceRelatedAssessmentPremiumTaxOffset": { "auth_ref": [ "r312" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of insurance-related assessment liability that is expected to be recovered through a premium tax offset based on current laws applied to in-force policies.", "label": "Loss Contingency Accrual, Insurance-related Assessment, Premium Tax Offset", "terseLabel": "Premium tax offsets" } } }, "localname": "LossContingencyAccrualInsuranceRelatedAssessmentPremiumTaxOffset", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LossContingencyEstimateOfPossibleLoss": { "auth_ref": [ "r318", "r322", "r324" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.", "label": "Loss Contingency, Estimate of Possible Loss", "terseLabel": "Estimated losses accrued related to legal matters" } } }, "localname": "LossContingencyEstimateOfPossibleLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability": { "auth_ref": [ "r311", "r312" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The liability as of the balance sheet date representing required funding mandated by statute or regulatory authority that is related directly or indirectly to underwriting activities, including pools for self-insurance and excluding premium taxes and income taxes. The funds derived from the assessments generally enable a government guarantor to pay insurance claims in the event that the underwriting insurer is insolvent or otherwise unable to meet its payment obligations.", "label": "Loss Contingency, Undiscounted Amount of Insurance-related Assessment Liability", "terseLabel": "Undiscounted liability balance for guaranty fund assessments" } } }, "localname": "LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesGuaranteesAndIndemnificationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ManagementServiceMember": { "auth_ref": [ "r362" ], "lang": { "en-US": { "role": { "documentation": "Contractually stipulated right to receive compensation for operating and managing business.", "label": "Management Service [Member]", "terseLabel": "Management fee revenue" } } }, "localname": "ManagementServiceMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MarketApproachValuationTechniqueMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Valuation approach using price and other relevant information generated by market transaction involving identical or comparable asset, liability, or group of assets and liabilities.", "label": "Market Approach Valuation Technique [Member]", "terseLabel": "Market comparables" } } }, "localname": "MarketApproachValuationTechniqueMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MarketableSecuritiesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Marketable Securities [Line Items]", "terseLabel": "Available-for-sale securities" } } }, "localname": "MarketableSecuritiesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_MarketableSecuritiesTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about investment in marketable security.", "label": "Marketable Securities [Table]" } } }, "localname": "MarketableSecuritiesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_MaterialReconcilingItemsMember": { "auth_ref": [ "r185", "r186" ], "lang": { "en-US": { "role": { "documentation": "Items used in reconciling reportable segments' amounts to consolidated amount. Excludes corporate-level activity.", "label": "Material Reconciling Items [Member]", "terseLabel": "Reconciling Items" } } }, "localname": "MaterialReconcilingItemsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MaximumLengthOfTimeHedgedInCashFlowHedge1": { "auth_ref": [ "r582" ], "lang": { "en-US": { "role": { "documentation": "Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Maximum Length of Time Hedged in Cash Flow Hedge", "terseLabel": "Maximum length of time hedging exposure to variability in future cash flows for forecasted transactions" } } }, "localname": "MaximumLengthOfTimeHedgedInCashFlowHedge1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "durationItemType" }, "us-gaap_MeasurementInputComparabilityAdjustmentMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using adjustment to observed price for similar asset or liability when identical transaction does not exist.", "label": "Measurement Input Comparability Adjustment [Member]", "terseLabel": "Comparability adjustment" } } }, "localname": "MeasurementInputComparabilityAdjustmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputCreditSpreadMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using amount above (below) yield between two debt instruments similar in maturity, but different in credit quality.", "label": "Measurement Input Credit Spread [Member]", "terseLabel": "Credit spread rate" } } }, "localname": "MeasurementInputCreditSpreadMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputDefaultRateMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using likelihood loan will not be repaid as proportion of outstanding loan.", "label": "Measurement Input Default Rate [Member]", "terseLabel": "Probability of default" } } }, "localname": "MeasurementInputDefaultRateMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using amount by which value of business ownership interest is reduced to reflect lack of ability to convert business interest into cash quickly.", "label": "Measurement Input Discount For Lack Of Marketability [Member]", "terseLabel": "Illiquidity premium" } } }, "localname": "MeasurementInputDiscountForLackOfMarketabilityMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputDiscountRateMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using interest rate to determine present value of future cash flows.", "label": "Measurement Input Discount Rate [Member]", "terseLabel": "Discount rate" } } }, "localname": "MeasurementInputDiscountRateMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputLapseRateMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using rate insurance policy terminates due to non-payment of premium.", "label": "Measurement Input Lapse Rate [Member]", "terseLabel": "Lapse rate" } } }, "localname": "MeasurementInputLapseRateMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputLongTermRevenueGrowthRateMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using compounded annualized rate of long-term growth in revenue.", "label": "Measurement Input Long Term Revenue Growth Rate [Member]", "terseLabel": "Average market rent growth rate" } } }, "localname": "MeasurementInputLongTermRevenueGrowthRateMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputLossSeverityMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using loss, including, but not limited to, interest and write-down of principal, incurred on defaulted security as proportion of principal balance.", "label": "Measurement Input Loss Severity [Member]", "terseLabel": "Potential loss severity" } } }, "localname": "MeasurementInputLossSeverityMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputPriceVolatilityMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Measurement input using rate at which price of security will increase (decrease) for given set of returns.", "label": "Measurement Input Price Volatility [Member]", "terseLabel": "Long-term equity market volatility" } } }, "localname": "MeasurementInputPriceVolatilityMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MeasurementInputTypeAxis": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Information by type of measurement input used to determine value of asset and liability.", "label": "Measurement Input Type [Axis]" } } }, "localname": "MeasurementInputTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_MeasurementInputTypeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Measurement input used to determine value of asset and liability.", "label": "Measurement Input Type [Domain]", "terseLabel": "Measurement Input Type [Domain]" } } }, "localname": "MeasurementInputTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_MinorityInterest": { "auth_ref": [ "r49", "r664", "r708" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).", "label": "Stockholders' Equity Attributable to Noncontrolling Interest", "terseLabel": "Noncontrolling interest" } } }, "localname": "MinorityInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_MinorityInterestChangeInRedemptionValue": { "auth_ref": [ "r342", "r343", "r344", "r355" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.", "label": "Noncontrolling Interest, Change in Redemption Value", "terseLabel": "Change in redemption value of redeemable noncontrolling interest" } } }, "localname": "MinorityInterestChangeInRedemptionValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders": { "auth_ref": [ "r354" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders.", "label": "Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders", "negatedLabel": "Distributions to noncontrolling interest" } } }, "localname": "MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_MinorityInterestDecreaseFromRedemptions": { "auth_ref": [ "r354", "r516", "r517" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).", "label": "Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests", "negatedLabel": "Purchase of subsidiary shares from noncontrolling interest" } } }, "localname": "MinorityInterestDecreaseFromRedemptions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet": { "auth_ref": [ "r713" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 4.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 4.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.", "label": "Mortgage Loans on Real Estate, Commercial and Consumer, Net", "terseLabel": "Mortgage loans" } } }, "localname": "MortgageLoansOnRealEstateCommercialAndConsumerNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_MovementAnalysisOfDeferredPolicyAcquisitionCostsRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]", "terseLabel": "Change in deferred acquisition costs" } } }, "localname": "MovementAnalysisOfDeferredPolicyAcquisitionCostsRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDeferredAcquisitionCostsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_MovementInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNetRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]", "terseLabel": "Change in unpaid claims" } } }, "localname": "MovementInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNetRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_NetCashProvidedByUsedInFinancingActivities": { "auth_ref": [ "r113" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 3.0, "parentTag": "us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.", "label": "Net Cash Provided by (Used in) Financing Activities", "totalLabel": "Net cash provided by (used in) financing activities" } } }, "localname": "NetCashProvidedByUsedInFinancingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Net Cash Provided by (Used in) Financing Activities [Abstract]", "terseLabel": "Financing activities" } } }, "localname": "NetCashProvidedByUsedInFinancingActivitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_NetCashProvidedByUsedInInvestingActivities": { "auth_ref": [ "r113" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 2.0, "parentTag": "us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.", "label": "Net Cash Provided by (Used in) Investing Activities", "totalLabel": "Net cash provided by (used in) investing activities" } } }, "localname": "NetCashProvidedByUsedInInvestingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Net Cash Provided by (Used in) Investing Activities [Abstract]", "terseLabel": "Investing activities" } } }, "localname": "NetCashProvidedByUsedInInvestingActivitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_NetCashProvidedByUsedInOperatingActivities": { "auth_ref": [ "r113", "r116", "r119" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 1.0, "parentTag": "us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.", "label": "Net Cash Provided by (Used in) Operating Activities", "terseLabel": "Net cash provided by (used in) operating activities", "totalLabel": "Net cash provided by (used in) operating activities" } } }, "localname": "NetCashProvidedByUsedInOperatingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Net Cash Provided by (Used in) Operating Activities [Abstract]", "terseLabel": "Operating activities" } } }, "localname": "NetCashProvidedByUsedInOperatingActivitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_NetIncomeLoss": { "auth_ref": [ "r73", "r76", "r85", "r119", "r162", "r675", "r729" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.", "label": "Net Income (Loss) Attributable to Parent", "terseLabel": "Net income attributable to PFG", "totalLabel": "Net income (loss) attributable to Principal Financial Group, Inc.", "verboseLabel": "Net income (loss) attributable to Principal Financial Group, Inc." } } }, "localname": "NetIncomeLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetIncomeLossAttributableToNoncontrollingInterest": { "auth_ref": [ "r73", "r76", "r520", "r529" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_NetIncomeLoss", "weight": -1.0 }, "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": 2.0, "parentTag": "us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of Net Income (Loss) attributable to noncontrolling interest.", "label": "Net Income (Loss) Attributable to Noncontrolling Interest", "terseLabel": "Net income (loss) attributable to noncontrolling interest" } } }, "localname": "NetIncomeLossAttributableToNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest": { "auth_ref": [ "r89" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.", "label": "Net Income (Loss) Attributable to Redeemable Noncontrolling Interest", "terseLabel": "Net income (loss) attributable to redeemable noncontrolling interest" } } }, "localname": "NetIncomeLossAttributableToRedeemableNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic": { "auth_ref": [ "r147", "r154" ], "calculation": { "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.", "label": "Net Income (Loss) Available to Common Stockholders, Basic", "totalLabel": "Total" } } }, "localname": "NetIncomeLossAvailableToCommonStockholdersBasic", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest": { "auth_ref": [ "r341", "r520", "r521" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after income tax of income (loss) including the portion attributable to nonredeemable noncontrolling interest. Excludes the portion attributable to redeemable noncontrolling interest recognized as temporary equity.", "label": "Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest", "terseLabel": "Net income (loss)" } } }, "localname": "NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_NetInvestmentIncome": { "auth_ref": [ "r731" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 }, "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 5.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": 1.0 }, "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails": { "order": 3.0, "parentTag": "pfg_OperatingRevenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.", "label": "Net Investment Income", "terseLabel": "Net investment income (loss)", "totalLabel": "Net investment income (loss)", "verboseLabel": "Net investment income (loss)" } } }, "localname": "NetInvestmentIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "New Accounting Pronouncements or Change in Accounting Principle [Line Items]", "terseLabel": "Recent Accounting Pronouncements" } } }, "localname": "NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable": { "auth_ref": [ "r146", "r148" ], "lang": { "en-US": { "role": { "documentation": "Summarization of the changes in an accounting principle or a new accounting pronouncement, including the line items affected by the change and the financial effects of the change on those particular line items.", "label": "New Accounting Pronouncements or Change in Accounting Principle [Table]" } } }, "localname": "NewAccountingPronouncementsOrChangeInAccountingPrincipleTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact.", "label": "New Accounting Pronouncements, Policy [Policy Text Block]", "terseLabel": "Recent Accounting Pronouncements - Policy" } } }, "localname": "NewAccountingPronouncementsPolicyPolicyTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_NoncontrollingInterestMember": { "auth_ref": [ "r511" ], "lang": { "en-US": { "role": { "documentation": "This element represents that portion of equity (net assets) in a subsidiary not attributable, directly or indirectly, to the parent. A noncontrolling interest is sometimes called a minority interest.", "label": "Noncontrolling Interest [Member]", "terseLabel": "Noncontrolling interest" } } }, "localname": "NoncontrollingInterestMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_NonqualifiedPlanMember": { "auth_ref": [ "r406" ], "lang": { "en-US": { "role": { "documentation": "Plan without tax-exempt status in accordance with applicable tax provision of designated taxing authority. Taxing authority includes, but is not limited to, U.S. Internal Revenue Service (IRS). Includes, but is not limited to, defined benefit and defined contribution plans.", "label": "Nonqualified Plan [Member]", "terseLabel": "Nonqualified benefit plans" } } }, "localname": "NonqualifiedPlanMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_NonredeemablePreferredStockMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Preferred shares that are not redeemable before liquidation of the entity. Preferred shares may provide a preferential dividend to the dividend on common stock and may take precedence over common stock in the event of a liquidation. Preferred shares typically represent an ownership interest in the company.", "label": "Nonredeemable Preferred Stock [Member]", "terseLabel": "Non-redeemable preferred stock" } } }, "localname": "NonredeemablePreferredStockMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_NotDesignatedAsHedgingInstrumentEconomicHedgeMember": { "auth_ref": [ "r541" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument, not designated as hedging instrument under Generally Accepted Accounting Principles (GAAP), used as economic hedge for exposure to risk.", "label": "Not Designated As Hedging Instrument Economic Hedge [Member]", "terseLabel": "Derivatives not designated as hedging instruments" } } }, "localname": "NotDesignatedAsHedgingInstrumentEconomicHedgeMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_NotesReceivableGross": { "auth_ref": [ "r265" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails": { "order": 1.0, "parentTag": "us-gaap_NotesReceivableNet", "weight": 1.0 }, "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before allowance for credit loss, of financing receivable.", "label": "Financing Receivable, Gross", "terseLabel": "Mortgage loans, Total amortized cost", "totalLabel": "Mortgage loans, Total amortized cost" } } }, "localname": "NotesReceivableGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_NotesReceivableNet": { "auth_ref": [ "r27", "r193", "r265" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.", "label": "Financing Receivable, Net", "totalLabel": "Mortgage loans, Total carrying value" } } }, "localname": "NotesReceivableNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent": { "auth_ref": [ "r69", "r80" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.", "label": "OCI, before Reclassifications, Net of Tax, Attributable to Parent", "terseLabel": "Other comprehensive income (loss) during the period, net of adjustments" } } }, "localname": "OciBeforeReclassificationsNetOfTaxAttributableToParent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OffsettingAssetsLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Offsetting Assets [Line Items]", "terseLabel": "Financial Asset Offsetting" } } }, "localname": "OffsettingAssetsLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OffsettingAssetsTable": { "auth_ref": [ "r51", "r52" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about derivative and financial assets that are subject to offsetting, including enforceable master netting arrangements.", "label": "Offsetting Assets [Table]" } } }, "localname": "OffsettingAssetsTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OffsettingAssetsTableTextBlock": { "auth_ref": [ "r51", "r52" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of derivative and other financial assets that are subject to offsetting, including master netting arrangements.", "label": "Offsetting Assets [Table Text Block]", "terseLabel": "Financial Assets Subject to Netting Agreements (Table)" } } }, "localname": "OffsettingAssetsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_OffsettingLiabilitiesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Offsetting Liabilities [Line Items]", "terseLabel": "Financial Liability Offsetting" } } }, "localname": "OffsettingLiabilitiesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OffsettingLiabilitiesTable": { "auth_ref": [ "r51", "r52" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about derivative and financial liabilities that are subject to offsetting, including enforceable master netting arrangements.", "label": "Offsetting Liabilities [Table]" } } }, "localname": "OffsettingLiabilitiesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsBalanceSheetOffsettingLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OffsettingLiabilitiesTableTextBlock": { "auth_ref": [ "r51", "r52" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of derivative and other financial liabilities that are subject to offsetting, including master netting arrangements.", "label": "Offsetting Liabilities [Table Text Block]", "terseLabel": "Financial Liabilities Subject to Netting Agreements (Table)" } } }, "localname": "OffsettingLiabilitiesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_OperatingLeaseCost": { "auth_ref": [ "r639", "r646" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 3.0, "parentTag": "us-gaap_LeaseCost", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.", "label": "Operating Lease, Cost", "terseLabel": "Operating lease cost" } } }, "localname": "OperatingLeaseCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLeaseLiabilitiesPaymentsDueRollingMaturityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Operating Lease Liabilities, Payments, Due, Rolling Maturity [Abstract]", "terseLabel": "Operating leases, payments due for the twelve months ending December 31:" } } }, "localname": "OperatingLeaseLiabilitiesPaymentsDueRollingMaturityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OperatingLeaseLiability": { "auth_ref": [ "r633" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 2.0, "parentTag": "pfg_TotalLeaseLiabilities", "weight": 1.0 }, "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetailscalc2": { "order": 2.0, "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Present value of lessee's discounted obligation for lease payments from operating lease.", "label": "Operating Lease, Liability", "terseLabel": "Present value of lease liabilities", "verboseLabel": "Operating lease liabilities" } } }, "localname": "OperatingLeaseLiability", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList": { "auth_ref": [ "r634" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of financial position that includes operating lease liability.", "label": "Operating Lease, Liability, Statement of Financial Position [Extensible List]" } } }, "localname": "OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_OperatingLeasePayments": { "auth_ref": [ "r637", "r641" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.", "label": "Operating Lease, Payments", "terseLabel": "Payments for operating leases" } } }, "localname": "OperatingLeasePayments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLeaseRightOfUseAsset": { "auth_ref": [ "r632" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 1.0, "parentTag": "pfg_TotalLeaseRightOfUseAssets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of lessee's right to use underlying asset under operating lease.", "label": "Operating Lease, Right-of-Use Asset", "verboseLabel": "Operating lease assets" } } }, "localname": "OperatingLeaseRightOfUseAsset", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList": { "auth_ref": [ "r634" ], "lang": { "en-US": { "role": { "documentation": "Indicates line item in statement of financial position that includes operating lease right-of-use asset.", "label": "Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]" } } }, "localname": "OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "extensibleListItemType" }, "us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent": { "auth_ref": [ "r643", "r646" ], "lang": { "en-US": { "role": { "documentation": "Weighted average discount rate for operating lease calculated at point in time.", "label": "Operating Lease, Weighted Average Discount Rate, Percent", "terseLabel": "Weighted-average discount rate, Operating leases" } } }, "localname": "OperatingLeaseWeightedAverageDiscountRatePercent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1": { "auth_ref": [ "r642", "r646" ], "lang": { "en-US": { "role": { "documentation": "Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.", "label": "Operating Lease, Weighted Average Remaining Lease Term", "terseLabel": "Weighted average remaining lease term, Operating leases" } } }, "localname": "OperatingLeaseWeightedAverageRemainingLeaseTerm1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "durationItemType" }, "us-gaap_OperatingLeasesRentExpenseNet": { "auth_ref": [ "r624" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.", "label": "Operating Leases, Rent Expense, Net", "terseLabel": "Operating lease rental expense" } } }, "localname": "OperatingLeasesRentExpenseNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLossCarryforwards": { "auth_ref": [ "r486" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.", "label": "Operating Loss Carryforwards", "terseLabel": "Net operating loss carryforwards" } } }, "localname": "OperatingLossCarryforwards", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingLossCarryforwardsValuationAllowance": { "auth_ref": [ "r460", "r483", "r487" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.", "label": "Operating Loss Carryforwards, Valuation Allowance", "terseLabel": "Valuation allowances on income tax benefits primarily associated with foreign net operating loss carryforwards" } } }, "localname": "OperatingLossCarryforwardsValuationAllowance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OperatingSegmentsMember": { "auth_ref": [ "r177", "r188" ], "lang": { "en-US": { "role": { "documentation": "Identifies components of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.", "label": "Operating Segments [Member]", "terseLabel": "Operating Segments" } } }, "localname": "OperatingSegmentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock": { "auth_ref": [ "r145", "r152", "r175", "r533" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for the general note to the financial statements for the reporting entity which may include, descriptions of the basis of presentation, business description, significant accounting policies, consolidations, reclassifications, new pronouncements not yet adopted and changes in accounting principles.", "label": "Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]", "terseLabel": "Nature of Operations and Significant Accounting Policies" } } }, "localname": "OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_OtherAssets": { "auth_ref": [ "r15", "r657", "r694" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 17.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 10.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of assets classified as other.", "label": "Other Assets", "terseLabel": "Other assets" } } }, "localname": "OtherAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax": { "auth_ref": [ "r64", "r66", "r396" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).", "label": "Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax", "terseLabel": "Prior service (benefit) cost" } } }, "localname": "OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPeriodIncreaseDecreaseAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]", "terseLabel": "Other changes recognized in accumulated other comprehensive (income) loss" } } }, "localname": "OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPeriodIncreaseDecreaseAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax": { "auth_ref": [ "r66", "r70", "r71", "r396" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 4.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.", "label": "Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax", "negatedLabel": "Amortization of prior service benefit (cost)" } } }, "localname": "OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax": { "auth_ref": [ "r69" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax", "weight": 1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount before tax and reclassification adjustments of other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss), before Reclassifications, before Tax", "terseLabel": "Other comprehensive income (loss) before reclassifications, pre-tax" } } }, "localname": "OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax": { "auth_ref": [ "r69", "r80" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax, before reclassification adjustments of other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss), before Reclassifications, Net of Tax", "totalLabel": "Other comprehensive income (loss) before reclassifications, after-tax" } } }, "localname": "OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax": { "auth_ref": [ "r67", "r499" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax", "weight": -1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossTax", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss) before Reclassifications, Tax", "negatedLabel": "Other comprehensive income (loss) before reclassifications, tax" } } }, "localname": "OtherComprehensiveIncomeLossBeforeReclassificationsTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossBeforeTax": { "auth_ref": [ "r246" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": 1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount before tax, after reclassification adjustments of other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss), before Tax", "totalLabel": "Other comprehensive income (loss), pre-tax" } } }, "localname": "OtherComprehensiveIncomeLossBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax": { "auth_ref": [ "r56", "r66", "r546", "r550", "r577" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.", "label": "Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax", "terseLabel": "Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships" } } }, "localname": "OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax": { "auth_ref": [ "r54", "r617" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 4.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.", "label": "Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax", "terseLabel": "Foreign currency translation adjustment" } } }, "localname": "OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossNetOfTax": { "auth_ref": [ "r74", "r77", "r80", "r347" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 2.0, "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax and reclassification adjustments of other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss), Net of Tax", "terseLabel": "Other comprehensive income (loss)", "totalLabel": "Other comprehensive income (loss)" } } }, "localname": "OtherComprehensiveIncomeLossNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Other Comprehensive Income (Loss), Net of Tax [Abstract]", "terseLabel": "Other comprehensive income (loss), net:" } } }, "localname": "OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "stringItemType" }, "us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent": { "auth_ref": [ "r74", "r77", "r513", "r514", "r522" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of other comprehensive income (loss) attributable to parent entity.", "label": "Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent", "totalLabel": "Other comprehensive income (loss) attributable to Principal Financial Group, Inc." } } }, "localname": "OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax": { "auth_ref": [ "r63", "r66" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 2.0, "parentTag": "us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.", "label": "Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax", "totalLabel": "Total recognized in pre-tax accumulated other comprehensive (income) loss" } } }, "localname": "OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax": { "auth_ref": [ "r63", "r66" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 5.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.", "label": "Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax", "negatedLabel": "Net unrecognized postretirement benefit obligation" } } }, "localname": "OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax": { "auth_ref": [ "r61", "r66", "r396" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 1.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.", "label": "Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax", "negatedLabel": "Net actuarial (gain) loss" } } }, "localname": "OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax": { "auth_ref": [ "r66", "r70", "r71", "r396" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails": { "order": 3.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.", "label": "Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax", "terseLabel": "Amortization of net gain (loss)" } } }, "localname": "OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeLossTax": { "auth_ref": [ "r67", "r499", "r501" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of tax expense (benefit) allocated to other comprehensive income (loss).", "label": "Other Comprehensive Income (Loss), Tax", "negatedTotalLabel": "Other comprehensive income (loss), tax" } } }, "localname": "OtherComprehensiveIncomeLossTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax": { "auth_ref": [ "r56", "r66", "r580" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).", "label": "Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax", "verboseLabel": "Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships" } } }, "localname": "OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherContractMember": { "auth_ref": [ "r385", "r559" ], "lang": { "en-US": { "role": { "documentation": "Derivative instrument whose primary underlying risk is classified as other.", "label": "Other Contract [Member]", "terseLabel": "Other contracts" } } }, "localname": "OtherContractMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDerivativesNotDesignatedAsHedgingInstrumentsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueOfDerivativesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_OtherDebtSecuritiesMember": { "auth_ref": [ "r229", "r271", "r385", "r597" ], "lang": { "en-US": { "role": { "documentation": "Investments in debt securities classified as other.", "label": "Other Debt Securities [Member]", "terseLabel": "Other debt obligations" } } }, "localname": "OtherDebtSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsChangesInLevel3FairValueMeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_OtherInvestments": { "auth_ref": [ "r35", "r717" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 4.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 7.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investments classified as other.", "label": "Other Investments, as Defined", "terseLabel": "Other investments", "verboseLabel": "Other investments (2019 and 2018 include $263.7 million and $457.9 million related to consolidated variable interest entities and $22.8 million and $23.6 million measured at fair value under the fair value option)" } } }, "localname": "OtherInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherLiabilities": { "auth_ref": [ "r671" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 9.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liabilities classified as other.", "label": "Other Liabilities", "terseLabel": "Other liabilities", "verboseLabel": "Other liabilities (2019 and 2018 include $124.4 million and $104.9 million related to consolidated variable interest entities)" } } }, "localname": "OtherLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherLongTermInvestmentsMember": { "auth_ref": [ "r799" ], "lang": { "en-US": { "role": { "documentation": "Long-term investments classified as other.", "label": "Other Long Term Investments [Member]", "terseLabel": "Investments: Other investments" } } }, "localname": "OtherLongTermInvestmentsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_OtherNoncashInvestingAndFinancingItemsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Other Noncash Investing and Financing Items [Abstract]", "verboseLabel": "Asset and liability changes resulting from exchange agreement to exit real estate joint ventures:" } } }, "localname": "OtherNoncashInvestingAndFinancingItemsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_OtherOperatingActivitiesCashFlowStatement": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 7.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 15.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities that are not separately disclosed in the statement of cash flows (for example, cash received or cash paid during the current period for miscellaneous operating activities, net change during the reporting period in other assets or other liabilities).", "label": "Other Operating Activities, Cash Flow Statement", "terseLabel": "Other" } } }, "localname": "OtherOperatingActivitiesCashFlowStatement", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherPolicyholderFunds": { "auth_ref": [ "r721" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 3.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount due to policyholders for funds held that are returnable under the terms of insurance contracts, classified as other.", "label": "Other Policyholder Funds", "terseLabel": "Other policyholder funds" } } }, "localname": "OtherPolicyholderFunds", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember": { "auth_ref": [ "r367", "r405", "r406", "r420" ], "lang": { "en-US": { "role": { "documentation": "Plan designed to provide other postretirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes pension benefits.", "label": "Other Postretirement Benefit Plans Defined Benefit [Member]", "terseLabel": "Other postretirement benefits" } } }, "localname": "OtherPostretirementBenefitPlansDefinedBenefitMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses": { "auth_ref": [ "r237" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses", "negatedLabel": "Credit losses for which an other-than-temporary impairment was previously recognized" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsNoPreviousImpairment": { "auth_ref": [ "r236" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which no such other than temporary impairment (OTTI) was previously recognized.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment", "negatedLabel": "Credit losses for which an other-than-temporary impairment was not previously recognized" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsNoPreviousImpairment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld": { "auth_ref": [ "r235", "r238" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held", "negatedPeriodEndLabel": "Ending balance", "negatedPeriodStartLabel": "Beginning balance" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]", "terseLabel": "Other-Than-Temporary Impairment Credit Losses Recognized in Net Income - Rollforward" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsAccumulatedCreditLossesForFixedMaturitiesWithBifurcatedCreditLossesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsTableTextBlock": { "auth_ref": [ "r234" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the amount of other than temporary impairment (OTTI) related to credit losses recognized in earnings including: (a) the beginning balance of the amount related to credit losses on debt securities held by the investor at the beginning of the period for which a portion of an OTTI was recognized in other comprehensive income; (b) additions for the amount related to the credit loss for which an OTTI was not previously recognized; (c) reductions for securities sold during the period (realized); (d) reductions for securities for which the amount previously recognized in other comprehensive income was recognized in earnings because the investor intends to sell the security or more likely than not will be required to sell the security before recovery of its amortized cost basis; (e) additional increases to the amount related to the credit loss for which an OTTI was previously recognized when the investor does not intend to sell the security and it is not more likely than not that the investor will be required to sell the security before recovery of its amortized cost basis; (f) reductions for increases in cash flows expected to be collected that are recognized over the remaining life of the security; and (g) the ending balance of the amount related to credit losses on debt securities held by the entity at the end of the period for which a portion of an OTTI was recognized in other comprehensive income.", "label": "Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block]", "terseLabel": "Other-Than-Temporary Impairment, Credit Losses Recognized in Earnings (Table)" } } }, "localname": "OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings": { "auth_ref": [ "r220" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": -1.0 }, "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 3.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings.", "label": "Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Recognized in Earnings", "negatedTerseLabel": "Fixed maturities, available-for-sale: Net impairment recoveries (losses)", "negatedTotalLabel": "Net impairment (losses) recoveries on available-for-sale securities" } } }, "localname": "OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableforsaleSecurities": { "auth_ref": [ "r59", "r220" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before tax, of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in other comprehensive income (OCI).", "label": "Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest, Available-for-sale Securities", "negatedLabel": "Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income", "negatedNetLabel": "Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income" } } }, "localname": "OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableforsaleSecurities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities": { "auth_ref": [], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 3.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.", "label": "Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities", "negatedTotalLabel": "Net impairment (losses) recoveries on available-for-sale securities" } } }, "localname": "OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsOtherThanTemporaryImpairmentsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_ParticipatingPoliciesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Participating Policies [Abstract]", "terseLabel": "Contractholder and Policyholder Liabilities" } } }, "localname": "ParticipatingPoliciesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce": { "auth_ref": [ "r720", "r778" ], "lang": { "en-US": { "role": { "documentation": "Percentage of participating insurance contract to insurance contracts in force.", "label": "Participating Policies as Percentage of Gross Insurance in Force", "terseLabel": "Participating business as a percentage of life insurance in force (as a percent)" } } }, "localname": "ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ParticipatingPolicyPercentageOfPremiumIncome": { "auth_ref": [ "r699", "r778" ], "lang": { "en-US": { "role": { "documentation": "Percentage of participating insurance to premium income.", "label": "Participating Policy, Percentage of Premium Income", "terseLabel": "Participating business as a percentage of life insurance premiums (as a percent)" } } }, "localname": "ParticipatingPolicyPercentageOfPremiumIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails" ], "xbrltype": "percentItemType" }, "us-gaap_PastDueFinancingReceivablesTableTextBlock": { "auth_ref": [ "r214", "r215", "r261", "r269" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of aging analysis for financing receivable.", "label": "Past Due Financing Receivables [Table Text Block]", "terseLabel": "Mortgage Loans Aging (Table)" } } }, "localname": "PastDueFinancingReceivablesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_PaymentsForDerivativeInstrumentFinancingActivities": { "auth_ref": [ "r108", "r112" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 4.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow for derivative instruments during the period, which are classified as financing activities, excluding those designated as hedging instruments.", "label": "Payments for Derivative Instrument, Financing Activities", "negatedLabel": "Payments for financing element derivatives" } } }, "localname": "PaymentsForDerivativeInstrumentFinancingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsForLossesAndLossAdjustmentExpense": { "auth_ref": [ "r115", "r756" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of payments to settle insured claims and pay costs incurred in the claims settlement process.", "label": "Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid", "totalLabel": "Total payments" } } }, "localname": "PaymentsForLossesAndLossAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsForProceedsFromOtherInvestingActivities": { "auth_ref": [ "r97", "r101", "r142" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 11.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash (inflow) outflow from investing activities classified as other.", "label": "Payments for (Proceeds from) Other Investing Activities", "negatedLabel": "Net change in other investments" } } }, "localname": "PaymentsForProceedsFromOtherInvestingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsForRepurchaseOfCommonStock": { "auth_ref": [ "r106" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 2.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow to reacquire common stock during the period.", "label": "Payments for Repurchase of Common Stock", "negatedLabel": "Acquisition of treasury stock" } } }, "localname": "PaymentsForRepurchaseOfCommonStock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsForRepurchaseOfEquityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Payments for Repurchase of Equity [Abstract]", "terseLabel": "Common stock share repurchase disclosures" } } }, "localname": "PaymentsForRepurchaseOfEquityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_PaymentsOfDistributionsToAffiliates": { "auth_ref": [ "r106" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The distributions of earnings to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.", "label": "Payments of Distributions to Affiliates", "terseLabel": "Extraordinary dividend to parent" } } }, "localname": "PaymentsOfDistributionsToAffiliates", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsOfDividendsCommonStock": { "auth_ref": [ "r106" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 7.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.", "label": "Payments of Ordinary Dividends, Common Stock", "negatedLabel": "Dividends to common stockholders" } } }, "localname": "PaymentsOfDividendsCommonStock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireBusinessesGross": { "auth_ref": [ "r99", "r508" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.", "label": "Payments to Acquire Businesses, Gross", "terseLabel": "Purchase price of acquired business in the form of cash to be paid at the closing" } } }, "localname": "PaymentsToAcquireBusinessesGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireHeldForSaleRealEstate": { "auth_ref": [ "r100" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 12.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow from the acquisition of a piece of land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.", "label": "Payments to Acquire Held-for-sale Real Estate", "negatedLabel": "Real estate acquired through operating activities" } } }, "localname": "PaymentsToAcquireHeldForSaleRealEstate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates": { "auth_ref": [ "r99" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 9.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity).", "label": "Payments to Acquire Interest in Subsidiaries and Affiliates", "negatedLabel": "Purchase of business or interests in subsidiaries, net of cash acquired" } } }, "localname": "PaymentsToAcquireInterestInSubsidiariesAndAffiliates", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireMarketableSecurities": { "auth_ref": [ "r219" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 1.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash outflow for purchase of marketable security.", "label": "Payments to Acquire Marketable Securities", "negatedLabel": "Fixed maturities available-for-sale and equity securities with intent to hold: Purchases" } } }, "localname": "PaymentsToAcquireMarketableSecurities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireMortgageNotesReceivable": { "auth_ref": [ "r98" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 4.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow from the purchase of receivables arising from the mortgage note on real estate.", "label": "Payments to Acquire Mortgage Notes Receivable", "negatedLabel": "Mortgage loans acquired or originated" } } }, "localname": "PaymentsToAcquireMortgageNotesReceivable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToAcquireRealEstateHeldForInvestment": { "auth_ref": [ "r101" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 6.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow associated with the purchase of real estate held for investment purposes.", "label": "Payments to Acquire Real Estate Held-for-investment", "negatedLabel": "Real estate acquired" } } }, "localname": "PaymentsToAcquireRealEstateHeldForInvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PaymentsToMinorityShareholders": { "auth_ref": [ "r109" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 5.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of cash outflow to a noncontrolling interest. Includes, but not limited to, reduction of noncontrolling interest ownership. Excludes dividends paid to the noncontrolling interest.", "label": "Payments to Noncontrolling Interests", "negatedLabel": "Purchase of subsidiary shares from noncontrolling interest" } } }, "localname": "PaymentsToMinorityShareholders", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock": { "auth_ref": [ "r421" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for pension and other postretirement benefits.", "label": "Pension and Other Postretirement Benefits Disclosure [Text Block]", "terseLabel": "Employee and Agent Benefits" } } }, "localname": "PensionAndOtherPostretirementBenefitsDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefits" ], "xbrltype": "textBlockItemType" }, "us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent": { "auth_ref": [ "r368", "r382", "r662", "r702" ], "calculation": { "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails": { "order": 2.0, "parentTag": "us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans.", "label": "Pension and Other Postretirement Defined Benefit Plans, Liabilities", "negatedLabel": "Amount recognized in other liabilities" } } }, "localname": "PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PensionPlansDefinedBenefitMember": { "auth_ref": [ "r366", "r405", "r406", "r420" ], "lang": { "en-US": { "role": { "documentation": "Plan designed to provide participant with pension benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes other postretirement benefits.", "label": "Pension Plans Defined Benefit [Member]", "terseLabel": "Pension benefits" } } }, "localname": "PensionPlansDefinedBenefitMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PerformanceSharesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Share-based payment arrangement awarded for meeting performance target.", "label": "Performance Shares [Member]", "terseLabel": "Performance Share Awards" } } }, "localname": "PerformanceSharesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PlanAssetCategoriesDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Defined benefit plan asset investment.", "label": "Plan Asset Categories [Domain]", "terseLabel": "Plan Asset Categories [Domain]" } } }, "localname": "PlanAssetCategoriesDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PlanNameAxis": { "auth_ref": [ "r423", "r452" ], "lang": { "en-US": { "role": { "documentation": "Information by plan name for share-based payment arrangement.", "label": "Plan Name [Axis]" } } }, "localname": "PlanNameAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_PlanNameDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Plan name for share-based payment arrangement.", "label": "Plan Name [Domain]", "terseLabel": "Stock-Based Compensation Plans [Domain]" } } }, "localname": "PlanNameDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PolicyLoansMember": { "auth_ref": [ "r799" ], "lang": { "en-US": { "role": { "documentation": "Loan issued by an insurance company, collateralized by the cash value of the borrower's life insurance policy.", "label": "Policy Loans [Member]", "terseLabel": "Policy loans" } } }, "localname": "PolicyLoansMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PolicyholderAccountsPolicy": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for contracts reported in separate accounts, including the extent and terms of minimum guarantees, basis of presentation for separate account assets and liabilities and related separate account activity, the liability valuation method and assumptions used in valuing each type of policyholder and contract holder account maintained by the entity.", "label": "Policyholder Accounts, Policy [Policy Text Block]", "terseLabel": "Separate Accounts - Policy" } } }, "localname": "PolicyholderAccountsPolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_PolicyholderBenefitsAndClaimsIncurredGross": { "auth_ref": [ "r736" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 1.0, "parentTag": "us-gaap_PolicyholderBenefitsAndClaimsIncurredNet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.", "label": "Policyholder Benefits and Claims Incurred, Direct", "terseLabel": "Benefits, claims and settlement expenses, Direct" } } }, "localname": "PolicyholderBenefitsAndClaimsIncurredGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PolicyholderBenefitsAndClaimsIncurredNet": { "auth_ref": [ "r685", "r736" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_BenefitsLossesAndExpenses", "weight": 1.0 }, "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails": { "order": 7.0, "parentTag": "us-gaap_GainLossOnDerivativeInstrumentsNetPretax", "weight": -1.0 }, "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.", "label": "Policyholder Benefits and Claims Incurred, Net", "negatedLabel": "Benefits, claims and settlement expenses", "terseLabel": "Benefits, claims and settlement expenses", "totalLabel": "Benefits, claims and settlement expenses" } } }, "localname": "PolicyholderBenefitsAndClaimsIncurredNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_PolicyholderBenefitsAndClaimsIncurredNetAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Policyholder Benefits and Claims Incurred, Net [Abstract]", "terseLabel": "Benefits, claims and settlement expenses:" } } }, "localname": "PolicyholderBenefitsAndClaimsIncurredNetAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_PolicyholderDividends": { "auth_ref": [ "r732", "r779" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 2.0, "parentTag": "us-gaap_BenefitsLossesAndExpenses", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of expense for dividends to policyholders.", "label": "Policyholder Dividends, Expense", "terseLabel": "Dividends to policyholders" } } }, "localname": "PolicyholderDividends", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_PortionAtFairValueFairValueDisclosureMember": { "auth_ref": [ "r604" ], "lang": { "en-US": { "role": { "documentation": "Measured at fair value for financial reporting purposes.", "label": "Portion At Fair Value Fair Value Disclosure [Member]", "terseLabel": "Portion at Fair Value Measurement [Member]" } } }, "localname": "PortionAtFairValueFairValueDisclosureMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PremiumsAndOtherReceivablesNet": { "auth_ref": [ "r725" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 11.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 4.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of all premiums and other types of receivables due from other persons or entities.", "label": "Premiums and Other Receivables, Net", "terseLabel": "Premiums due and other receivables" } } }, "localname": "PremiumsAndOtherReceivablesNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_PremiumsEarnedNet": { "auth_ref": [ "r673", "r726", "r743", "r795" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_Revenues", "weight": 1.0 }, "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails": { "order": 2.0, "parentTag": "pfg_OperatingRevenues", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned.", "label": "Premiums Earned, Net", "terseLabel": "Premiums and other considerations", "totalLabel": "Premiums and other considerations", "verboseLabel": "Premiums net amount" } } }, "localname": "PremiumsEarnedNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities": { "auth_ref": [ "r104", "r112" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 3.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow provided by derivative instruments during the period, which are classified as financing activities, excluding those designated as hedging instruments.", "label": "Proceeds from Derivative Instrument, Financing Activities", "terseLabel": "Proceeds from financing element derivatives" } } }, "localname": "ProceedsFromDerivativeInstrumentFinancingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromIssuanceOfCommonStock": { "auth_ref": [ "r102" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 1.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow from the additional capital contribution to the entity.", "label": "Proceeds from Issuance of Common Stock", "terseLabel": "Issuance of common stock" } } }, "localname": "ProceedsFromIssuanceOfCommonStock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromIssuanceOfLongTermDebt": { "auth_ref": [ "r103" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 8.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.", "label": "Proceeds from Issuance of Long-term Debt", "terseLabel": "Issuance of long-term debt" } } }, "localname": "ProceedsFromIssuanceOfLongTermDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromMinorityShareholders": { "auth_ref": [ "r105" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 6.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow from a noncontrolling interest. Includes, but is not limited to, purchase of additional shares or other increase in noncontrolling interest ownership.", "label": "Proceeds from Noncontrolling Interests", "terseLabel": "Sale of subsidiary shares to noncontrolling interest" } } }, "localname": "ProceedsFromMinorityShareholders", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromPaymentsForOtherFinancingActivities": { "auth_ref": [ "r105", "r109", "r142" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 15.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow (outflow) from financing activities classified as other.", "label": "Proceeds from (Payments for) Other Financing Activities", "terseLabel": "Other" } } }, "localname": "ProceedsFromPaymentsForOtherFinancingActivities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromRepaymentsOfShortTermDebt": { "auth_ref": [ "r142" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 10.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer.", "label": "Proceeds from (Repayments of) Short-term Debt", "terseLabel": "Net proceeds from (repayments of) short-term borrowings" } } }, "localname": "ProceedsFromRepaymentsOfShortTermDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromSaleAndCollectionOfMortgageNotesReceivable": { "auth_ref": [ "r95" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 5.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow from proceeds from sale of receivables arising from the mortgage note on real estate; includes collections on mortgage notes receivable that are not classified as operating cash flows.", "label": "Proceeds from Sale and Collection of Mortgage Notes Receivable", "terseLabel": "Mortgage loans sold or repaid" } } }, "localname": "ProceedsFromSaleAndCollectionOfMortgageNotesReceivable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt": { "auth_ref": [ "r94", "r95", "r219" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).", "label": "Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds", "terseLabel": "Proceeds from sales of investments in fixed maturities, available-for-sale" } } }, "localname": "ProceedsFromSaleOfAvailableForSaleSecuritiesDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment": { "auth_ref": [ "r96" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 7.0, "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.", "label": "Proceeds from Sale of Real Estate Held-for-investment", "terseLabel": "Real estate sold" } } }, "localname": "ProceedsFromSaleOfRealEstateHeldforinvestment", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans": { "auth_ref": [ "r97" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 13.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The cash inflow from proceeds From Sales of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans.", "label": "Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans", "terseLabel": "Real estate sold through operating activities" } } }, "localname": "ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProceedsFromStockOptionsExercised": { "auth_ref": [ "r102", "r453" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cash inflow from exercise of option under share-based payment arrangement.", "label": "Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options", "terseLabel": "Cash received from stock options exercised" } } }, "localname": "ProceedsFromStockOptionsExercised", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProfitLoss": { "auth_ref": [ "r73", "r76", "r111", "r181", "r189", "r513", "r519", "r521", "r529", "r530" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "us-gaap_NetIncomeLoss", "weight": 1.0 }, "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": 1.0, "parentTag": "us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 1.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 1.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome": { "order": 1.0, "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.", "label": "Net Income (Loss), Including Portion Attributable to Noncontrolling Interest", "terseLabel": "Net income (loss)", "totalLabel": "Net income (loss)" } } }, "localname": "ProfitLoss", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows", "http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_PropertyPlantAndEquipmentNet": { "auth_ref": [ "r13", "r14", "r308", "r712" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 13.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 6.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.", "label": "Property, Plant and Equipment, Net", "terseLabel": "Property and equipment" } } }, "localname": "PropertyPlantAndEquipmentNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_ProvisionForLoanLeaseAndOtherLosses": { "auth_ref": [ "r117", "r195", "r677" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.", "label": "Provision for Loan, Lease, and Other Losses", "terseLabel": "Provision: Mortgage loan valuation allowance" } } }, "localname": "ProvisionForLoanLeaseAndOtherLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_PublicUtilityBondsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents investments by the reporting entity in fixed maturity securities (bonds) issued by a public utility.", "label": "Public Utility Bonds [Member]", "terseLabel": "Public utilities" } } }, "localname": "PublicUtilityBondsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_PublicUtilityEquitiesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "This item represents investments by the reporting entity in equity securities issued by a public utility.", "label": "Public Utility Equities [Member]", "terseLabel": "Common stocks: Public Utilities" } } }, "localname": "PublicUtilityEquitiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_QualifiedPlanMember": { "auth_ref": [ "r406" ], "lang": { "en-US": { "role": { "documentation": "Plan with tax-exempt status designed and operated in accordance with applicable tax provision of designated taxing authority. Taxing authority includes, but is not limited to, U.S. Internal Revenue Service (IRS). Includes, but is not limited to, defined benefit and defined contribution plans.", "label": "Qualified Plan [Member]", "terseLabel": "Qualified benefit plans" } } }, "localname": "QualifiedPlanMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails" ], "xbrltype": "domainItemType" }, "us-gaap_QuarterlyFinancialInformationDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Quarterly Results of Operations (Unaudited)" } } }, "localname": "QuarterlyFinancialInformationDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_QuarterlyFinancialInformationTextBlock": { "auth_ref": [ "r167" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for quarterly financial data. Includes, but is not limited to, tabular presentation of financial information for fiscal quarters, effect of year-end adjustments, and an explanation of matters or transactions that affect comparability of the information.", "label": "Quarterly Financial Information [Text Block]", "terseLabel": "Quarterly Results of Operations (Unaudited)" } } }, "localname": "QuarterlyFinancialInformationTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnaudited" ], "xbrltype": "textBlockItemType" }, "us-gaap_RealEstateAcquiredInSatisfactionOfDebtMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Real estate taken in settlement of troubled loans through surrender or foreclosure.", "label": "Real Estate Acquired In Satisfaction Of Debt [Member]", "terseLabel": "Real estate acquired in satisfaction of debt" } } }, "localname": "RealEstateAcquiredInSatisfactionOfDebtMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RealEstateFundsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Investments in funds that invest in commercial or residential real estate.", "label": "Real Estate Funds [Member]", "terseLabel": "Real estate mutual fund" } } }, "localname": "RealEstateFundsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RealEstateHeldforsale": { "auth_ref": [ "r716" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.", "label": "Real Estate Held-for-sale", "terseLabel": "Real estate held for sale" } } }, "localname": "RealEstateHeldforsale", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesCashAndCashEquivalentsInvestmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_RealEstateInvestmentMember": { "auth_ref": [ "r829" ], "lang": { "en-US": { "role": { "documentation": "This element represents direct equity investments in real estate projects (Land, buildings and improvements owned for income production and capital accretion potential) and certain loans accounted for as real estate investments. For loans accounted for as real estate investments, the entity (lender) has virtually the same risks and rewards as those of owners or joint venture participants. Such arrangements are treated as if the entity actually has an ownership interest in the property. In such arrangements, the entity (lender) participates in expected residual profits, which may be in the form of an equity kicker or a higher than usual effective interest rate. At the outset and during the construction and development of the property, the borrower generally has little or no equity in the property and the entity's (lender's) only source of repayment is the property. The entity (lender) generally (a) agrees to provide substantially all funds to acquire, develop, and construct the property, (b) funds the commitment or origination fees or both, and (c) funds interest during the development and construction of the property.", "label": "Real Estate Investment [Member]", "terseLabel": "Other real estate" } } }, "localname": "RealEstateInvestmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RealEstateInvestments": { "auth_ref": [ "r714" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 5.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 5.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of real estate investments, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; (7) other real estate investments; (8) real estate joint ventures; and (9) unconsolidated real estate and other joint ventures not separately presented.", "label": "Real Estate Investments, Net", "terseLabel": "Real estate", "verboseLabel": "Real estate (2019 and 2018 include $457.6 million and $364.0 million related to consolidated variable interest entities)" } } }, "localname": "RealEstateInvestments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_RealEstateInvestmentsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Real Estate Investments, Net [Abstract]", "terseLabel": "Real estate" } } }, "localname": "RealEstateInvestmentsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "stringItemType" }, "us-gaap_RealizedInvestmentGainsLosses": { "auth_ref": [ "r735" ], "calculation": { "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails": { "order": 9.0, "parentTag": "us-gaap_GainLossOnInvestments", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.", "label": "Realized Investment Gains (Losses)", "terseLabel": "Realized capital gains (losses)", "verboseLabel": "Net pre-tax realized capital gain" } } }, "localname": "RealizedInvestmentGainsLosses", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails", "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_RealizedInvestmentGainsLossesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Realized Investment Gains (Losses) [Abstract]", "terseLabel": "Major components of net realized capital gains (losses) on investments" } } }, "localname": "RealizedInvestmentGainsLossesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetRealizedCapitalGainsAndLossesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax": { "auth_ref": [ "r69", "r72" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 1.0, "parentTag": "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax", "weight": 1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossBeforeTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount before tax of reclassification adjustments of other comprehensive income (loss).", "label": "Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax", "negatedLabel": "Reclassification from accumulated other comprehensive income, pre-tax", "verboseLabel": "Gain (loss) reclassified from AOCI on derivatives" } } }, "localname": "ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax": { "auth_ref": [ "r69", "r72", "r80" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": null, "parentTag": null, "root": true, "weight": null }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of reclassification adjustments of other comprehensive income (loss).", "label": "Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax", "negatedTotalLabel": "Reclassification from accumulated other comprehensive income, after-tax" } } }, "localname": "ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent": { "auth_ref": [ "r69", "r80" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails": { "order": 2.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.", "label": "Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent", "negatedLabel": "Amounts reclassified from accumulated other comprehensive income (loss)" } } }, "localname": "ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReclassificationFromAociCurrentPeriodTax": { "auth_ref": [ "r67", "r71", "r499" ], "calculation": { "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossCalc2Details": { "order": 2.0, "parentTag": "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax", "weight": -1.0 }, "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails": { "order": 3.0, "parentTag": "us-gaap_OtherComprehensiveIncomeLossTax", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).", "label": "Reclassification from AOCI, Current Period, Tax", "terseLabel": "Reclassification from accumulated other comprehensive income, tax" } } }, "localname": "ReclassificationFromAociCurrentPeriodTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by item reclassified out of accumulated other comprehensive income (loss).", "label": "Reclassification out of Accumulated Other Comprehensive Income [Axis]" } } }, "localname": "ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Item reclassified out of accumulated other comprehensive income (loss).", "label": "Reclassification Out Of Accumulated Other Comprehensive Income [Domain]", "terseLabel": "Reclassification out of Accumulated Other Comprehensive Income [Domain]" } } }, "localname": "ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Identifies item reclassified out of accumulated other comprehensive income (loss).", "label": "Reclassification Out Of Accumulated Other Comprehensive Income [Member]", "terseLabel": "Gain (loss) reclassified from AOCI on derivatives" } } }, "localname": "ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable": { "auth_ref": [ "r183", "r186" ], "lang": { "en-US": { "role": { "documentation": "Identification, description, and amounts of all significant reconciling items in the reconciliation of total assets from reportable segments to the entity's consolidated assets.", "label": "Reconciliation of Assets from Segment to Consolidated [Table]" } } }, "localname": "ReconciliationOfAssetsFromSegmentToConsolidatedTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock": { "auth_ref": [ "r183", "r186" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of all significant reconciling items in the reconciliation of total assets from reportable segments to the entity's consolidated assets.", "label": "Reconciliation of Assets from Segment to Consolidated [Table Text Block]", "terseLabel": "Reconciliation of Assets from Segment to Consolidated (Table)" } } }, "localname": "ReconciliationOfAssetsFromSegmentToConsolidatedTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable": { "auth_ref": [ "r184", "r186" ], "lang": { "en-US": { "role": { "documentation": "Identification, description, and amounts of all significant reconciling items in the reconciliation of a significant segment item of information disclosed (for example, liabilities) other than profit (loss), revenues, or assets, between reportable segments in total and the entity's consolidated total for that significant segment item disclosed.", "label": "Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table]" } } }, "localname": "ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTextBlock": { "auth_ref": [ "r184", "r186" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of each significant reconciling item, other than profit (loss), revenues, or assets, in the reconciliation of totals of such items in reportable segments to the entity's corresponding consolidated amount.", "label": "Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table Text Block]", "terseLabel": "Reconciliation of Other Significant Reconciling Items from Segments to Consolidated (Table)" } } }, "localname": "ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]", "terseLabel": "Changes in Unrecognized Tax Benefits" } } }, "localname": "ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount": { "auth_ref": [ "r339", "r340", "r342", "r343" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.", "label": "Redeemable Noncontrolling Interest, Equity, Carrying Amount", "periodEndLabel": "Redeemable noncontrolling interest, balance at end of period", "periodStartLabel": "Redeemable noncontrolling interest, balance at beginning of period", "terseLabel": "Redeemable noncontrolling interest (2019 and 2018 include $215.4 million and $325.7 million related to consolidated variable interest entities)", "verboseLabel": "Redeemable noncontrolling interest" } } }, "localname": "RedeemableNoncontrollingInterestEquityCarryingAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_RedeemableNoncontrollingInterestTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of redeemable noncontrolling interest (as defined) included in the statement of financial position as either a liability or temporary equity. As of the date of the statement of financial position, such redeemable noncontrolling interest is currently redeemable, as defined, for cash or other assets of the entity at (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the entity.", "label": "Redeemable Noncontrolling Interest [Table Text Block]", "terseLabel": "Redeemable Noncontrolling Interest (Table)" } } }, "localname": "RedeemableNoncontrollingInterestTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_RedeemablePreferredStockMember": { "auth_ref": [ "r10", "r338" ], "lang": { "en-US": { "role": { "documentation": "Description of type or class of redeemable preferred stock. For instance, cumulative preferred stock, noncumulative preferred stock, convertible or series.", "label": "Redeemable Preferred Stock [Member]", "terseLabel": "Redeemable preferred stock" } } }, "localname": "RedeemablePreferredStockMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ReductionsInOtherAssetsAmount": { "auth_ref": [ "r36" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of significant reductions in the period of other assets (current, noncurrent, or unclassified).", "label": "Reductions in Other Assets, Amount", "terseLabel": "Cumulative effect adjustment, decrease to other assets" } } }, "localname": "ReductionsInOtherAssetsAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReinsuranceAccountingPolicy": { "auth_ref": [ "r128", "r685", "r686", "r719", "r796", "r797" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of reinsurance accounting policy, for example, but not limited to, description of the methodologies and assumptions underlying determination of reinsurance recoverables, reinsurance payables and retention policy.", "label": "Reinsurance Accounting Policy [Policy Text Block]", "terseLabel": "Reinsurance - Policy" } } }, "localname": "ReinsuranceAccountingPolicy", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_ReinsuranceDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Reinsurance Disclosures [Abstract]", "terseLabel": "Reinsurance" } } }, "localname": "ReinsuranceDisclosuresAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed": { "auth_ref": [ "r685" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 2.0, "parentTag": "us-gaap_PolicyholderBenefitsAndClaimsIncurredNet", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of policy benefits and costs incurred for policies assumed.", "label": "Policyholder Benefits and Claims Incurred, Assumed", "verboseLabel": "Benefits, claims and settlement expenses, Assumed" } } }, "localname": "ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded": { "auth_ref": [ "r685" ], "calculation": { "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails": { "order": 3.0, "parentTag": "us-gaap_PolicyholderBenefitsAndClaimsIncurredNet", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of reduction of provision for policy benefits and costs incurred for policies ceded.", "label": "Policyholder Benefits and Claims Incurred, Ceded", "negatedLabel": "Benefits, claims and settlement expenses, Ceded" } } }, "localname": "ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Premiums Earned, Net [Abstract]", "terseLabel": "Premiums and other considerations:", "verboseLabel": "Premiums:" } } }, "localname": "ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails", "http://principal.com/role/DisclosureScheduleIvReinsuranceDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments": { "auth_ref": [ "r687", "r753", "r754", "r757" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 2.0, "parentTag": "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.", "label": "Reinsurance Recoverable for Unpaid Claims and Claims Adjustments", "periodEndLabel": "Balance at end of period, reinsurance recoverables for unpaid claims", "periodStartLabel": "Balance at beginning of period, reinsurance recoverables for unpaid claims" } } }, "localname": "ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_RepaymentsOfLongTermDebt": { "auth_ref": [ "r107" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 9.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.", "label": "Repayments of Long-term Debt", "negatedLabel": "Principal repayments of long-term debt", "verboseLabel": "Principal repayments of long-term debt" } } }, "localname": "RepaymentsOfLongTermDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ResidentialMortgageBackedSecuritiesMember": { "auth_ref": [ "r222", "r385" ], "lang": { "en-US": { "role": { "documentation": "Securities collateralized by residential real estate mortgage loans.", "label": "Residential Mortgage Backed Securities [Member]", "terseLabel": "Residential mortgage-backed pass-through securities" } } }, "localname": "ResidentialMortgageBackedSecuritiesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails", "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ResidentialMortgageMember": { "auth_ref": [ "r268" ], "lang": { "en-US": { "role": { "documentation": "Loan to purchase or refinance residential real estate for example, but not limited to, a home, in which the real estate itself serves as collateral for the loan.", "label": "Residential Mortgage [Member]", "terseLabel": "Residential mortgage loans" } } }, "localname": "ResidentialMortgageMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails", "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RestrictedStockUnitsRSUMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Share instrument which is convertible to stock or an equivalent amount of cash, after a specified period of time or when specified performance conditions are met.", "label": "Restricted Stock Units R S U [Member]", "terseLabel": "Restricted Stock Units" } } }, "localname": "RestrictedStockUnitsRSUMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RetainedEarningsAccumulatedDeficit": { "auth_ref": [ "r29", "r354", "r706" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 3.0, "parentTag": "us-gaap_StockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cumulative amount of the reporting entity's undistributed earnings or deficit.", "label": "Retained Earnings (Accumulated Deficit)", "terseLabel": "Retained earnings (accumulated deficit)" } } }, "localname": "RetainedEarningsAccumulatedDeficit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_RetainedEarningsMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "The cumulative amount of the reporting entity's undistributed earnings or deficit.", "label": "Retained Earnings [Member]", "terseLabel": "Retained earnings (accumulated deficit)" } } }, "localname": "RetainedEarningsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_RetirementPlanTaxStatusAxis": { "auth_ref": [ "r406" ], "lang": { "en-US": { "role": { "documentation": "Information by tax status of plan designed to provide retirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans.", "label": "Retirement Plan Tax Status [Axis]" } } }, "localname": "RetirementPlanTaxStatusAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_RetirementPlanTaxStatusDomain": { "auth_ref": [ "r406" ], "lang": { "en-US": { "role": { "documentation": "Tax status of plan designed to provide retirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans.", "label": "Retirement Plan Tax Status [Domain]", "terseLabel": "Retirement Plan Tax Status [Domain]" } } }, "localname": "RetirementPlanTaxStatusDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyFinancialStatementFootnotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RetirementPlanTypeAxis": { "auth_ref": [ "r366", "r367", "r405", "r406", "r420" ], "lang": { "en-US": { "role": { "documentation": "Information by type of retirement benefit plan. Includes, but is not limited to, retirement benefit arrangement for defined benefit pension and other postretirement plans, retirement benefit arrangement for defined contribution pension and other postretirement plans, and special and contractual termination benefits payable upon retirement.", "label": "Retirement Plan Type [Axis]" } } }, "localname": "RetirementPlanTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_RetirementPlanTypeDomain": { "auth_ref": [ "r366", "r367", "r405", "r406", "r420" ], "lang": { "en-US": { "role": { "documentation": "Type of plan designed to provide participants with retirement benefits. Includes, but is not limited to, retirement benefit arrangement for defined benefit pension and other postretirement plans, retirement benefit arrangement for defined contribution pension and other postretirement plans, and special and contractual termination benefits payable upon retirement.", "label": "Retirement Plan Type [Domain]", "terseLabel": "Retirement Plan Type [Domain]" } } }, "localname": "RetirementPlanTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDefinedContributionAndDeferredCompensationPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_RevenueFromContractWithCustomerAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Revenues from Contracts with Customers" } } }, "localname": "RevenueFromContractWithCustomerAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax": { "auth_ref": [ "r360", "r361" ], "calculation": { "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails": { "order": 1.0, "parentTag": "pfg_InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.", "label": "Revenue from Contract with Customer, Excluding Assessed Tax", "terseLabel": "Total segment revenue from contracts with customers", "verboseLabel": "Total revenues from contracts with customers" } } }, "localname": "RevenueFromContractWithCustomerExcludingAssessedTax", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_RevenueFromContractWithCustomerTextBlock": { "auth_ref": [ "r365" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.", "label": "Revenue from Contract with Customer [Text Block]", "terseLabel": "Revenues from Contracts with Customers" } } }, "localname": "RevenueFromContractWithCustomerTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomers" ], "xbrltype": "textBlockItemType" }, "us-gaap_RevenuePracticalExpedientIncrementalCostOfObtainingContract": { "auth_ref": [ "r283", "r359" ], "lang": { "en-US": { "role": { "documentation": "Indicates (true false) whether practical expedient was elected to recognize incremental cost of obtaining contract as expense when incurred if amortization period would have been one year or less.", "label": "Revenue, Practical Expedient, Incremental Cost of Obtaining Contract [true/false]", "terseLabel": "Practical expedient, incremental costs of obtaining a contract" } } }, "localname": "RevenuePracticalExpedientIncrementalCostOfObtainingContract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersContractCostsDetails" ], "xbrltype": "booleanItemType" }, "us-gaap_Revenues": { "auth_ref": [ "r83", "r176", "r177", "r187" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails": { "order": 1.0, "parentTag": "pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes", "weight": 1.0 }, "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).", "label": "Revenues", "terseLabel": "Total revenues", "totalLabel": "Total revenues" } } }, "localname": "Revenues", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "monetaryItemType" }, "us-gaap_RevenuesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Revenues [Abstract]", "terseLabel": "Revenues" } } }, "localname": "RevenuesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfOperationsDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfOperationsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfOperations" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable": { "auth_ref": [ "r48" ], "lang": { "en-US": { "role": { "documentation": "Schedule itemizing specific types of trade accounts and notes receivable, and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables.", "label": "Schedule of Accounts, Notes, Loans and Financing Receivable [Table]", "terseLabel": "Mortgage Loans [Table]" } } }, "localname": "ScheduleOfAccountsNotesLoansAndFinancingReceivableTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock": { "auth_ref": [ "r48" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables.", "label": "Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]", "terseLabel": "Mortgage Loans (Table)" } } }, "localname": "ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock": { "auth_ref": [ "r407", "r408", "r418" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of benefit obligation and plan assets of defined benefit plan with accumulated benefit obligation in excess of plan assets.", "label": "Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]", "terseLabel": "Accumulated Benefit Obligation in Excess of Plan Assets (Table)" } } }, "localname": "ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock": { "auth_ref": [ "r69" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the components of accumulated other comprehensive income (loss).", "label": "Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]", "terseLabel": "Accumulated Other Comprehensive Income (Loss) (Table)" } } }, "localname": "ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock": { "auth_ref": [ "r383" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.", "label": "Schedule of Allocation of Plan Assets [Table Text Block]", "terseLabel": "Fair Value of Plan Assets (Table)" } } }, "localname": "ScheduleOfAllocationOfPlanAssetsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock": { "auth_ref": [ "r396" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the net gain (loss) and net prior service cost or credit recognized in other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, and reclassification adjustments of other comprehensive income (loss) for the period, as those amounts, including amortization of the net transition asset or obligation, are recognized as components of net periodic benefit cost.", "label": "Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]", "terseLabel": "Amounts Recognized in Net Periodic Benefit Cost and Accumulated Other Comprehensive (Income) Loss (Table)" } } }, "localname": "ScheduleOfAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value.", "label": "Schedule of Available-for-sale Securities Reconciliation [Table Text Block]", "terseLabel": "Fixed Maturities and Equity Securities Available-for-Sale (Table)" } } }, "localname": "ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable": { "auth_ref": [ "r504", "r505" ], "lang": { "en-US": { "role": { "documentation": "Schedule reflecting each material business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities.", "label": "Schedule of Business Acquisitions, by Acquisition [Table]" } } }, "localname": "ScheduleOfBusinessAcquisitionsByAcquisitionTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfCashFlowHedgesIncludedInAccumulatedOtherComprehensiveIncomeLossTableTextBlock": { "auth_ref": [ "r551" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of gain (loss) on derivative and nonderivative instruments designated and qualifying as cash flow hedge recorded in accumulated other comprehensive income (AOCI) and reclassified into earnings.", "label": "Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]", "terseLabel": "Cash Flow Hedges (Table)" } } }, "localname": "ScheduleOfCashFlowHedgesIncludedInAccumulatedOtherComprehensiveIncomeLossTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfClosedBlockAssetsAndLiabilities": { "auth_ref": [ "r806", "r818" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of summarized financial data of the closed block, typically including the liabilities of the closed block, assets allocated thereto, and maximum expected future earnings from the operations thereof.", "label": "Schedule of Closed Block Assets and Liabilities [Table Text Block]", "terseLabel": "Closed Block Liabilities and Assets Designated to the Closed Block (Table)" } } }, "localname": "ScheduleOfClosedBlockAssetsAndLiabilities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureClosedBlockTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock": { "auth_ref": [ "r492" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years.", "label": "Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]", "terseLabel": "Income Tax Expense (Benefit) from Continuing Operations (Table)" } } }, "localname": "ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfCreditDerivativesTable": { "auth_ref": [ "r568", "r572", "r573" ], "lang": { "en-US": { "role": { "documentation": "Schedule of credit derivatives, including information about each credit derivative, or each group of similar credit derivatives, including (a) the nature of the credit derivative - its term, how it arose, the events or circumstances that would require the seller to perform under the credit derivative, and the current status of the payment/performance risk of the credit derivative; (b) the maximum potential amount of future payments (undiscounted) the seller could be required to make under the credit derivative; (c) the current fair value of the credit derivative; and (d) the nature of any recourse provisions under the credit derivative, and any assets held either as collateral or by third parties.", "label": "Schedule of Credit Derivatives [Table]" } } }, "localname": "ScheduleOfCreditDerivativesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfDebtInstrumentsTextBlock": { "auth_ref": [ "r44", "r135", "r348", "r351", "r352", "r353", "r620", "r621", "r623", "r683" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.", "label": "Schedule of Long-term Debt Instruments [Table Text Block]", "terseLabel": "Long-Term Debt (Table)" } } }, "localname": "ScheduleOfDebtInstrumentsTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock": { "auth_ref": [ "r484" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets.", "label": "Schedule of Deferred Tax Assets and Liabilities [Table Text Block]", "terseLabel": "Components of Net Deferred Income Taxes (Table)" } } }, "localname": "ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable": { "auth_ref": [ "r405", "r406", "r409", "r410", "r418" ], "lang": { "en-US": { "role": { "documentation": "Disclosures about an individual defined benefit pension plan or an other postretirement defined benefit plan. It may be appropriate to group certain similar plans. Also includes schedule for fair value of plan assets by major categories of plan assets by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), Significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).", "label": "Schedule of Defined Benefit Plans Disclosures [Table]" } } }, "localname": "ScheduleOfDefinedBenefitPlansDisclosuresTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsAboInExcessOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsBenefitObligationAndFundedStatusDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsContributionsAndEstimatedFutureBenefitPaymentsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsNetPeriodicBenefitCostDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPensionPlanChangesAndPlanGainsLossesDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsPlanInformationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsSupplementalInformationQualifiedAndNonqualifiedPlansDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTargetPlanAssetAllocationDetails", "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsWeightedAverageAssumptionsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock": { "auth_ref": [ "r549" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position.", "label": "Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]", "terseLabel": "Derivative Financial Instruments, Fair Value Disclosures (Table)" } } }, "localname": "ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock": { "auth_ref": [ "r162" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations.", "label": "Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]", "terseLabel": "Earnings Per Common Share (Table)" } } }, "localname": "ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesTableTextBlock": { "auth_ref": [ "r402" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the effect of a one-percentage-point increase and the effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs and the accumulated postretirement benefit obligation for health care benefits.", "label": "Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]", "terseLabel": "Effects of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Table)" } } }, "localname": "ScheduleOfEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock": { "auth_ref": [ "r465" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations.", "label": "Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]", "terseLabel": "Reconciliation Between U.S. Corporate Income Tax Rate and Effective Income Tax Rate from Continuing Operations (Table)" } } }, "localname": "ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfEquityMethodInvestmentsLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Schedule of Equity Method Investments [Line Items]" } } }, "localname": "ScheduleOfEquityMethodInvestmentsLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfEquityMethodInvestmentsTable": { "auth_ref": [ "r250" ], "lang": { "en-US": { "role": { "documentation": "Summarization of information required and determined to be disclosed concerning equity method investments in common stock. The summarized information includes: (a) the name of each investee or group of investees for which combined disclosure is appropriate, (2) the percentage ownership of common stock, (3) the difference, if any, between the carrying amount of an investment and the value of the underlying equity in the net assets and the accounting treatment of difference, if any, and (4) the aggregate value of each identified investment based on its quoted market price, if available.", "label": "Schedule of Equity Method Investments [Table]" } } }, "localname": "ScheduleOfEquityMethodInvestmentsTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsRealEstateDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock": { "auth_ref": [ "r388" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter.", "label": "Schedule of Expected Benefit Payments [Table Text Block]", "terseLabel": "Estimated Future Benefit Payments (Table)" } } }, "localname": "ScheduleOfExpectedBenefitPaymentsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock": { "auth_ref": [ "r586", "r587" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).", "label": "Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]", "terseLabel": "Fair Value (Table)" } } }, "localname": "ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable": { "auth_ref": [ "r260" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about allowance for credit loss on financing receivable.", "label": "Schedule of Financing Receivable, Allowance for Credit Losses [Table]", "terseLabel": "Mortgage Loan Valuation Allowance [Table]" } } }, "localname": "ScheduleOfFinancingReceivableAllowanceForCreditLossesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanValuationAllowanceDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable": { "auth_ref": [ "r266", "r268" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about credit quality indicator for financing receivable.", "label": "Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table]", "terseLabel": "Mortgage Loans Credit Quality [Table]" } } }, "localname": "ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoanCreditMonitoringDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock": { "auth_ref": [ "r214", "r264" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of financing receivable on nonaccrual status.", "label": "Schedule of Financing Receivables, Non Accrual Status [Table Text Block]", "terseLabel": "Non-Accrual Mortgage Loans (Table)" } } }, "localname": "ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfFinancingReceivablesPastDueTable": { "auth_ref": [ "r261", "r269" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about aging analysis for financing receivable.", "label": "Schedule of Financing Receivables Past Due [Table]", "terseLabel": "Mortgage Loan Aging [Table]" } } }, "localname": "ScheduleOfFinancingReceivablesPastDueTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsMortgageLoansNonAccrualAndAgingDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock": { "auth_ref": [ "r294", "r299" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, by either major class or business segment.", "label": "Schedule of Finite-Lived Intangible Assets [Table Text Block]", "terseLabel": "Finite Lived Intangible Assets (Table)" } } }, "localname": "ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfGoodwillTable": { "auth_ref": [ "r290", "r291" ], "lang": { "en-US": { "role": { "documentation": "Schedule of goodwill and the changes during the year due to acquisition, sale, impairment or for other reasons.", "label": "Schedule of Goodwill [Table]" } } }, "localname": "ScheduleOfGoodwillTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfGoodwillTextBlock": { "auth_ref": [ "r290", "r291" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.", "label": "Schedule of Goodwill [Table Text Block]", "terseLabel": "Goodwill (Table)" } } }, "localname": "ScheduleOfGoodwillTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfHealthCareCostTrendRatesTableTextBlock": { "auth_ref": [ "r401" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the assumed health care cost trend rates for the next year used to measure the expected cost of benefits covered by the plans, including the ultimate trend rate(s) and when that rate is expected to be achieved.", "label": "Schedule of Health Care Cost Trend Rates [Table Text Block]", "terseLabel": "Assumed Health Care Cost Trend Rates (Table)" } } }, "localname": "ScheduleOfHealthCareCostTrendRatesTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfImpairedFinancingReceivableTable": { "auth_ref": [ "r208" ], "lang": { "en-US": { "role": { "documentation": "Schedule of the recorded investment, unpaid principal balance, associated allowance, average recorded investment, accounting policies, and interest income recognized on the accrual and cash basis for impaired financing receivables by class of financing receivable.", "label": "Schedule of Impaired Financing Receivable [Table]", "terseLabel": "Impaired Mortgage Loans [Table]" } } }, "localname": "ScheduleOfImpairedFinancingReceivableTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsImpairedMortgageLoansDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock": { "auth_ref": [ "r136" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of income before income tax between domestic and foreign jurisdictions.", "label": "Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]", "terseLabel": "Income Before Income Taxes, Domestic and Foreign (Table)" } } }, "localname": "ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable": { "auth_ref": [ "r303", "r305" ], "lang": { "en-US": { "role": { "documentation": "Schedule of assets, excluding financial assets and goodwill, lacking physical substance and exist in perpetuity.", "label": "Schedule of Indefinite-Lived Intangible Assets [Table]", "terseLabel": "Indefinite Lived Intangible Assets [Table]" } } }, "localname": "ScheduleOfIndefiniteLivedIntangibleAssetsTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsIndefiniteLivedIntangibleAssetsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Net Investment Income [Line Items]", "terseLabel": "Major categories of net investment income" } } }, "localname": "ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable": { "auth_ref": [ "r90", "r92", "r93", "r734" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about investment income, including, but not limited to, interest and dividend income and amortization of discount (premium) derived from debt and equity securities. Excludes realized and unrealized gain (loss) on investments.", "label": "Schedule of Investment Income [Table]" } } }, "localname": "ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsNetInvestmentIncomeDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense": { "auth_ref": [ "r758" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the activity in the reserve for settling insured claims and expenses incurred in the claims settlement process for the period. The estimated liability includes the amount of money that will be required for future payments of (a) claims that have been reported to the insurer, (b) claims related to insured events that have occurred but that have not been reported to the insurer as of the date the liability is estimated, and (c) claim adjustment expenses. Claim adjustment expenses include costs incurred in the claim settlement process such as legal fees; outside adjuster fees; and costs to record, process, and adjust claims.", "label": "Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]", "terseLabel": "Liability for Unpaid Claims (Table)" } } }, "localname": "ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock": { "auth_ref": [ "r331" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.", "label": "Schedule of Maturities of Long-term Debt [Table Text Block]", "terseLabel": "Future Annual Maturities of Long-Term Debt (Table)" } } }, "localname": "ScheduleOfMaturitiesOfLongTermDebtTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfNetBenefitCostsTableTextBlock": { "auth_ref": [ "r390" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.", "label": "Schedule of Net Benefit Costs [Table Text Block]", "terseLabel": "Components of Net Periodic Benefit Cost (Income) (Table)" } } }, "localname": "ScheduleOfNetBenefitCostsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfNetFundedStatusTableTextBlock": { "auth_ref": [ "r382" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of net funded status of pension plans and/or other employee benefit plans.", "label": "Schedule of Net Funded Status [Table Text Block]", "terseLabel": "Obligations and Funded Status (Table)" } } }, "localname": "ScheduleOfNetFundedStatusTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock": { "auth_ref": [ "r432" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the changes in outstanding nonvested performance-based units.", "label": "Schedule of Nonvested Performance-based Units Activity [Table Text Block]", "terseLabel": "Nonvested Performance Share Awards Activity (Table)" } } }, "localname": "ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock": { "auth_ref": [ "r432" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the changes in outstanding nonvested restricted stock units.", "label": "Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]", "terseLabel": "Nonvested Restricted Stock Units Activity (Table)" } } }, "localname": "ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock": { "auth_ref": [ "r536" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the notional amounts of outstanding derivative positions.", "label": "Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]", "terseLabel": "Derivative Financial Instruments, Exposure (Table)" } } }, "localname": "ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock": { "auth_ref": [ "r552", "r554" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of derivative instrument not designated or qualifying as hedging instrument.", "label": "Derivatives Not Designated as Hedging Instruments [Table Text Block]", "terseLabel": "Derivatives Not Designated as Hedging Instruments (Table)" } } }, "localname": "ScheduleOfOtherDerivativesNotDesignatedAsHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock": { "auth_ref": [ "r166" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of quarterly financial data. Includes, but is not limited to, financial information for fiscal quarters, cumulative effect of a change in accounting principle and earnings per share data.", "label": "Schedule of Quarterly Financial Information [Table Text Block]", "terseLabel": "Quarterly Results of Operations (Table)" } } }, "localname": "ScheduleOfQuarterlyFinancialInformationTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureQuarterlyResultsOfOperationsUnauditedTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable": { "auth_ref": [ "r423", "r452" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about share-based payment arrangement.", "label": "Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]", "terseLabel": "Stock-Based Compensation Plans [Table]" } } }, "localname": "ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock": { "auth_ref": [ "r452" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of option exercise prices, by grouped ranges, including the upper and lower limits of the price range, the number of shares under option, weighted average exercise price and remaining contractual option terms.", "label": "Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]", "terseLabel": "Nonqualified Stock Options Remaining Contractual Lives and Range of Exercise Prices (Table)" } } }, "localname": "ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock": { "auth_ref": [ "r427", "r436", "r439" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.", "label": "Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]", "terseLabel": "Nonqualified Stock Options Status (Table)" } } }, "localname": "ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock": { "auth_ref": [ "r443" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.", "label": "Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]", "terseLabel": "Nonqualified Stock Options Fair Value (Table)" } } }, "localname": "ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfShortTermDebtTable": { "auth_ref": [ "r40" ], "lang": { "en-US": { "role": { "documentation": "A table or schedule providing information pertaining to borrowings under which repayment was required in less than twelve months (or normal operating cycle, if longer) after its issuance. It may include: (1) description of the short-term debt arrangement; (2) identification of the lender or type of lender; (3) repayment terms; (4) weighted average interest rate; (5) carrying amount of funds borrowed under the specified short-term debt arrangement as of the balance sheet date and measures of the maximum and average amount outstanding during the period; (6) description of the refinancing of a short-term obligation when that obligation is excluded from current liabilities in the balance sheet; and (7) amount of a short-term obligation that has been excluded from current liabilities in the balance sheet because of a refinancing of the obligation.", "label": "Schedule of Short-term Debt [Table]" } } }, "localname": "ScheduleOfShortTermDebtTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfShortTermDebtTextBlock": { "auth_ref": [ "r40" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of short-term debt arrangements (having initial terms of repayment within one year or the normal operating cycle, if longer) including: (1) description of the short-term debt arrangement; (2) identification of the lender or type of lender; (3) repayment terms; (4) weighted average interest rate; (5) carrying amount of funds borrowed under the specified short-term debt arrangement as of the balance sheet date; (6) description of the refinancing of a short-term obligation when that obligation is excluded from current liabilities in the balance sheet; and (7) amount of a short-term obligation that has been excluded from current liabilities in the balance sheet because of a refinancing of the obligation.", "label": "Schedule of Short-term Debt [Table Text Block]", "terseLabel": "Short-Term Debt (Table)" } } }, "localname": "ScheduleOfShortTermDebtTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfStockByClassTable": { "auth_ref": [ "r45", "r133", "r337", "r345", "r346", "r348", "r349", "r350", "r351", "r352", "r353", "r354" ], "lang": { "en-US": { "role": { "documentation": "Schedule detailing information related to equity by class of stock. Class of stock includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. It also includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity.", "label": "Schedule of Stock by Class [Table]" } } }, "localname": "ScheduleOfStockByClassTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ScheduleOfStockByClassTextBlock": { "auth_ref": [ "r24", "r25", "r26", "r129", "r338", "r345", "r346", "r348", "r349", "r350", "r351", "r352", "r353", "r354" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.", "label": "Schedule of Stock by Class [Table Text Block]", "terseLabel": "Reconciliation of Outstanding Common Shares (Table)" } } }, "localname": "ScheduleOfStockByClassTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock": { "auth_ref": [ "r232" ], "lang": { "en-US": { "role": { "documentation": "For all investments in an unrealized loss position, including those for which other-than-temporary impairments have not been recognized in earnings (including investments for which a portion of an other-than-temporary impairment has been recognized in other comprehensive income), a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of unrealized losses (that is, the amount by which amortized cost basis exceeds fair value).", "label": "Schedule of Unrealized Loss on Investments [Table Text Block]", "terseLabel": "Gross Unrealized Losses for Fixed Maturities and Equity Securities (Table)" } } }, "localname": "ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInvestmentsTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_SegmentDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Components of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.", "label": "Segment [Domain]", "terseLabel": "Segments [Domain]" } } }, "localname": "SegmentDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "us-gaap_SegmentReportingAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Segment Information" } } }, "localname": "SegmentReportingAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_SegmentReportingAssetReconcilingItemLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Segment Reporting, Asset Reconciling Item [Line Items]", "terseLabel": "Segment Information: Assets" } } }, "localname": "SegmentReportingAssetReconcilingItemLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SegmentReportingDisclosureTextBlock": { "auth_ref": [ "r192" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.", "label": "Segment Reporting Disclosure [Text Block]", "terseLabel": "Segment Information" } } }, "localname": "SegmentReportingDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformation" ], "xbrltype": "textBlockItemType" }, "us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Segment Reporting, Other Significant Reconciling Item [Line Items]", "terseLabel": "Segment Information: Income tax expense (benefit)", "verboseLabel": "Segment Information: Depreciation and amortization expense" } } }, "localname": "SegmentReportingOtherSignificantReconcilingItemLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SeniorNotesMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Bond that takes priority over other debt securities sold by the issuer. In the event the issuer goes bankrupt, senior debt holders receive priority for (must receive) repayment prior to (relative to) junior and unsecured (general) creditors.", "label": "Senior Notes [Member]", "terseLabel": "Senior notes" } } }, "localname": "SeniorNotesMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtSeniorNotesAndJuniorSubordinatedNotesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_SeparateAccountAssets": { "auth_ref": [ "r695", "r798", "r799", "r802" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 16.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 2.0, "parentTag": "us-gaap_AssetsFairValueDisclosure", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 9.0, "parentTag": "us-gaap_Assets", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of asset at fair value held for benefit of separate account policyholder.", "label": "Separate Account Assets", "terseLabel": "Separate account assets", "verboseLabel": "Separate account assets (2019 and 2018 include $39,130.3 million and $37,183.3 million related to consolidated variable interest entities)" } } }, "localname": "SeparateAccountAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_SeparateAccountsDisclosureAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Separate Accounts Disclosure [Abstract]", "terseLabel": "Separate Accounts" } } }, "localname": "SeparateAccountsDisclosureAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesOtherVariousPoliciesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SeparateAccountsLiability": { "auth_ref": [ "r705", "r798", "r800", "r801", "r803" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 8.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of liability for variable contract in which all or portion of contract holder's funds is allocated to specific separate account and supported by assets held in separate account.", "label": "Separate Accounts, Liability", "terseLabel": "Separate account liabilities (2019 and 2018 include $39,130.3 million and $37,183.3 million related to consolidated variable interest entities)", "verboseLabel": "Separate account liabilities" } } }, "localname": "SeparateAccountsLiability", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShareBasedCompensation": { "auth_ref": [ "r117" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails": { "order": 5.0, "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows": { "order": 5.0, "parentTag": "us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of noncash expense for share-based payment arrangement.", "label": "Share-based Compensation", "terseLabel": "Stock-based compensation" } } }, "localname": "ShareBasedCompensation", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1": { "auth_ref": [ "r424" ], "lang": { "en-US": { "role": { "documentation": "Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period", "terseLabel": "Vesting period" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "durationItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]", "terseLabel": "Other award and unit disclosures" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod": { "auth_ref": [ "r434" ], "lang": { "en-US": { "role": { "documentation": "The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period", "terseLabel": "Awards or units granted (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue": { "auth_ref": [ "r434" ], "lang": { "en-US": { "role": { "documentation": "The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value", "terseLabel": "Awards or units granted, Weighted-average grant-date fair value (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber": { "auth_ref": [ "r433" ], "lang": { "en-US": { "role": { "documentation": "The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number", "periodEndLabel": "Awards or units outstanding at end of period (in shares)", "periodStartLabel": "Awards or units outstanding at beginning of period (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]", "terseLabel": "Change in nonvested units outstanding" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue": { "auth_ref": [ "r433" ], "lang": { "en-US": { "role": { "documentation": "Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value", "periodEndLabel": "Awards or units outstanding at end of period, Weighted-average grant-date fair value (in dollars per share)", "periodStartLabel": "Awards or units outstanding at beginning of period, Weighted-average grant-date fair value (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod": { "auth_ref": [ "r435" ], "lang": { "en-US": { "role": { "documentation": "The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period", "terseLabel": "Awards or units vested (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue": { "auth_ref": [ "r435" ], "lang": { "en-US": { "role": { "documentation": "The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value", "terseLabel": "Awards or units vested, Weighted-average grant-date fair value (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]", "terseLabel": "Assumptions used to estimate fair value of stock options granted during period" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate": { "auth_ref": [ "r446" ], "lang": { "en-US": { "role": { "documentation": "The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate", "terseLabel": "Weighted-average expected dividend yield (as a percent)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate": { "auth_ref": [ "r445" ], "lang": { "en-US": { "role": { "documentation": "The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate", "terseLabel": "Weighted-average expected volatility (as a percent)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate": { "auth_ref": [ "r447" ], "lang": { "en-US": { "role": { "documentation": "The risk-free interest rate assumption that is used in valuing an option on its own shares.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate", "terseLabel": "Weighted-average risk-free interest rate (as a percent)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Share-based Compensation Arrangement by Share-based Payment Award [Line Items]", "terseLabel": "Stock-Based Compensation Plans - Disclosures" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant": { "auth_ref": [ "r452" ], "lang": { "en-US": { "role": { "documentation": "The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant", "terseLabel": "Maximum number of new shares of common stock available for grant (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber": { "auth_ref": [ "r430" ], "lang": { "en-US": { "role": { "documentation": "The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number", "terseLabel": "Options exercisable at end of period (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice": { "auth_ref": [ "r430" ], "lang": { "en-US": { "role": { "documentation": "The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price", "terseLabel": "Options exercisable at end of period, Weighted-average exercise price (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue": { "auth_ref": [ "r438" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value", "terseLabel": "Total intrinsic value of options exercised" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Gross number of share options (or share units) granted during the period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross", "terseLabel": "Options granted (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue": { "auth_ref": [ "r437" ], "lang": { "en-US": { "role": { "documentation": "The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value", "terseLabel": "Weighted-average estimated fair value of stock options granted (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue": { "auth_ref": [ "r452" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value", "terseLabel": "Options outstanding at end of period, Intrinsic value" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber": { "auth_ref": [ "r429", "r452" ], "lang": { "en-US": { "role": { "documentation": "Number of options outstanding, including both vested and non-vested options.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number", "periodEndLabel": "Options outstanding at end of period (in shares)", "periodStartLabel": "Options outstanding at beginning of period (in shares)", "terseLabel": "Number of options outstanding (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]", "terseLabel": "Change in options outstanding" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice": { "auth_ref": [ "r428" ], "lang": { "en-US": { "role": { "documentation": "Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price", "periodEndLabel": "Options outstanding at end of period, Weighted-average exercise price (in dollars per share)", "periodStartLabel": "Options outstanding at beginning of period, Weighted-average exercise price (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue": { "auth_ref": [ "r439" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value", "terseLabel": "Options vested or expected to vest at end of period, Intrinsic value" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber": { "auth_ref": [ "r440" ], "lang": { "en-US": { "role": { "documentation": "Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number", "terseLabel": "Options vested or expected to vest at end of period (in shares)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice": { "auth_ref": [ "r440" ], "lang": { "en-US": { "role": { "documentation": "Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price", "terseLabel": "Options vested or expected to vest at end of period, Weighted-average exercise price (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain": { "auth_ref": [ "r422", "r426" ], "lang": { "en-US": { "role": { "documentation": "Award under share-based payment arrangement.", "label": "Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain]", "terseLabel": "Stock-Based Compensation by Award Type [Domain]" } } }, "localname": "ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails", "http://principal.com/role/DisclosureStockBasedCompensationPlansPerformanceShareAwardsAndRestrictedStockUnitsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Weighted average price at which option holders acquired shares when converting their stock options into shares.", "label": "Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price", "terseLabel": "Options exercised, Weighted-average exercise price (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.", "label": "Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price", "terseLabel": "Options granted, Weighted-average exercise price (in dollars per share)" } } }, "localname": "ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis": { "auth_ref": [ "r442" ], "lang": { "en-US": { "role": { "documentation": "Information by range of option prices pertaining to options granted.", "label": "Exercise Price Range [Axis]" } } }, "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain": { "auth_ref": [ "r448" ], "lang": { "en-US": { "role": { "documentation": "Supplementary information on outstanding and exercisable share awards as of the balance sheet date which stratifies outstanding options by ranges of exercise prices.", "label": "Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Domain]", "terseLabel": "Stock Option Plans Exercise Price Ranges [Domain]" } } }, "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit": { "auth_ref": [ "r448" ], "lang": { "en-US": { "role": { "documentation": "The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.", "label": "Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit", "terseLabel": "Lower limit of exercise price range (in dollars per share)" } } }, "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit": { "auth_ref": [ "r448" ], "lang": { "en-US": { "role": { "documentation": "The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.", "label": "Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit", "terseLabel": "Upper limit of exercise price range (in dollars per share)" } } }, "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "perShareItemType" }, "us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1": { "auth_ref": [ "r449" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cost expensed and capitalized for award under share-based payment arrangement.", "label": "Allocated Share-based Compensation Expense", "terseLabel": "Compensation cost" } } }, "localname": "SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansStockBasedAwardsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod": { "auth_ref": [ "r425" ], "lang": { "en-US": { "role": { "documentation": "Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period", "terseLabel": "Option expiration period" } } }, "localname": "SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "durationItemType" }, "us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1": { "auth_ref": [ "r444", "r454" ], "lang": { "en-US": { "role": { "documentation": "Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term", "terseLabel": "Weighted-average expected term" } } }, "localname": "SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsAssumptionsAndOtherDisclosuresDetails" ], "xbrltype": "durationItemType" }, "us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1": { "auth_ref": [ "r452" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value", "terseLabel": "Options exercisable at end of period, Intrinsic value" } } }, "localname": "SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2": { "auth_ref": [ "r441" ], "lang": { "en-US": { "role": { "documentation": "Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term", "terseLabel": "Weighted-average remaining contractual life for stock options exercisable" } } }, "localname": "SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "durationItemType" }, "us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2": { "auth_ref": [ "r440" ], "lang": { "en-US": { "role": { "documentation": "Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.", "label": "Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term", "terseLabel": "Weighted-average remaining contractual life" } } }, "localname": "SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsRangeOfExercisePricesDetails" ], "xbrltype": "durationItemType" }, "us-gaap_SharesOutstanding": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Number of shares issued which are neither cancelled nor held in the treasury.", "label": "Shares, Outstanding", "periodEndLabel": "Outstanding shares at end of period", "periodStartLabel": "Outstanding shares at beginning of period" } } }, "localname": "SharesOutstanding", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_ShortDurationContractsDiscountedLiabilitiesAmount": { "auth_ref": [ "r688", "r768" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails": { "order": 2.0, "parentTag": "us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The carrying amount as of the balance sheet date of loss reserves carried at present value.", "label": "Short-Duration Contracts, Discounted Liabilities, Amount", "terseLabel": "Carrying amount of liabilities for unpaid claims", "totalLabel": "Liability for unpaid claims - short duration contracts" } } }, "localname": "ShortDurationContractsDiscountedLiabilitiesAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortDurationContractsDiscountedLiabilitiesDiscountRate": { "auth_ref": [ "r769" ], "lang": { "en-US": { "role": { "documentation": "Discount rate used to obtain present value of liability for unpaid claim and claim adjustment expense for short-duration contract issued by insurance entity.", "label": "Short-Duration Contracts, Discounted Liabilities, Discount Rate", "terseLabel": "Discount rate" } } }, "localname": "ShortDurationContractsDiscountedLiabilitiesDiscountRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortDurationInsuranceContractAccidentYear2019Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2019 in which covered event occurs under terms of short-duration insurance contract.", "label": "Short Duration Insurance Contract Accident Year2019 [Member]", "terseLabel": "Incurral year 2019" } } }, "localname": "ShortDurationInsuranceContractAccidentYear2019Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2017 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Short Duration Insurance Contracts Accident Year2017 [Member]", "terseLabel": "Incurral year 2017" } } }, "localname": "ShortDurationInsuranceContractsAccidentYear2017Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2018 in which covered event occurs under terms of short-duration insurance contract.", "label": "Short Duration Insurance Contracts Accident Year2018 [Member]", "terseLabel": "Incurral year 2018" } } }, "localname": "ShortDurationInsuranceContractsAccidentYear2018Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortTermBorrowings": { "auth_ref": [ "r16", "r659", "r703" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 4.0, "parentTag": "us-gaap_Liabilities", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.", "label": "Short-term Debt", "negatedLabel": "Short-term debt", "terseLabel": "Short-term debt" } } }, "localname": "ShortTermBorrowings", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureDebtShortTermDebtDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFinancialInstrumentsNotReportedAtFairValueDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortTermDebtLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Short-term Debt [Line Items]", "terseLabel": "Short-Term Debt" } } }, "localname": "ShortTermDebtLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortTermDebtTypeAxis": { "auth_ref": [ "r40" ], "lang": { "en-US": { "role": { "documentation": "Information by type of short-term debt arrangement.", "label": "Short-term Debt, Type [Axis]" } } }, "localname": "ShortTermDebtTypeAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortTermDebtTypeDomain": { "auth_ref": [ "r37" ], "lang": { "en-US": { "role": { "documentation": "Type of short-term debt arrangement, such as notes, line of credit, commercial paper, asset-based financing, project financing, letter of credit financing.", "label": "Short Term Debt Type [Domain]", "terseLabel": "Short-Term Debt Instrument Types [Domain]" } } }, "localname": "ShortTermDebtTypeDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortTermDebtWeightedAverageInterestRate": { "auth_ref": [ "r38" ], "lang": { "en-US": { "role": { "documentation": "Weighted average interest rate of short-term debt outstanding calculated at point in time.", "label": "Short-term Debt, Weighted Average Interest Rate", "terseLabel": "Weighted-average interest rates on short-term borrowings (as a percent)" } } }, "localname": "ShortTermDebtWeightedAverageInterestRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtShortTermDebtDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2010Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2010 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2010 [Member]", "terseLabel": "Incurral year 2010" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2010Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2011Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2011 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2011 [Member]", "terseLabel": "Incurral year 2011" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2011Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2012Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2012 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2012 [Member]", "terseLabel": "Incurral year 2012" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2012Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2013 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2013 [Member]", "terseLabel": "Incurral year 2013" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2013Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2014 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2014 [Member]", "terseLabel": "Incurral year 2014" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2014Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2015 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2015 [Member]", "terseLabel": "Incurral year 2015" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2015Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year 2016 in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year2016 [Member]", "terseLabel": "Incurral year 2016" } } }, "localname": "ShortdurationInsuranceContractsAccidentYear2016Member", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYearAxis": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Information by accident year in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Short-duration Insurance Contracts, Accident Year [Axis]" } } }, "localname": "ShortdurationInsuranceContractsAccidentYearAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsAccidentYearDomain": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Accident year in which a covered event occurs under the terms of the short-duration insurance contract.", "label": "Shortduration Insurance Contracts Accident Year [Domain]", "terseLabel": "Short-duration Insurance Contracts, Accident Year [Domain]" } } }, "localname": "ShortdurationInsuranceContractsAccidentYearDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about undiscounted information about claims development by accident year for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Claims Development [Table]" } } }, "localname": "ShortdurationInsuranceContractsClaimsDevelopmentTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTableTextBlock": { "auth_ref": [ "r761" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of undiscounted information about claims development by accident year for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Claims Development [Table Text Block]", "terseLabel": "Claims Development (Table)" } } }, "localname": "ShortdurationInsuranceContractsClaimsDevelopmentTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet": { "auth_ref": [ "r760" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails": { "order": 2.0, "parentTag": "us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.", "label": "Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net", "terseLabel": "Net cumulative paid claims" } } }, "localname": "ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsDiscountedLiabilitiesAggregateDiscount": { "auth_ref": [ "r770" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of cumulative discount related to the time value of money deducted from short-duration insurance contract liabilities that are reported at present value.", "label": "Short-duration Insurance Contracts, Discounted Liabilities, Aggregate Discount", "negatedLabel": "Impact of discounting", "terseLabel": "Aggregate amount of discount" } } }, "localname": "ShortdurationInsuranceContractsDiscountedLiabilitiesAggregateDiscount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsDiscountedLiabilitiesInterestAccretion": { "auth_ref": [ "r771", "r772" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of interest accretion recognized for short-duration insurance contract liabilities that are reported at present value.", "label": "Short-duration Insurance Contracts, Discounted Liabilities, Interest Accretion", "terseLabel": "Interest accretion" } } }, "localname": "ShortdurationInsuranceContractsDiscountedLiabilitiesInterestAccretion", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsDiscountedLiabilitiesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Short-duration Insurance Contracts, Discounted Liabilities [Line Items]" } } }, "localname": "ShortdurationInsuranceContractsDiscountedLiabilitiesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsDiscountedLiabilitiesTable": { "auth_ref": [ "r773" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about liabilities for unpaid claims and claim adjustment expenses that are presented at present value.", "label": "Short-duration Insurance Contracts, Discounted Liabilities [Table]" } } }, "localname": "ShortdurationInsuranceContractsDiscountedLiabilitiesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesDiscountingTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Short-duration Insurance Contracts, Historical Claims Duration [Line Items]" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about average annual percentage payout of incurred claims by age, after reinsurance, for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration [Table]" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the eighth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Eight", "terseLabel": "Year 8" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the fifth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Five", "terseLabel": "Year 5" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the fourth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Four", "terseLabel": "Year 4" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the ninth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Nine", "terseLabel": "Year 9" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the first year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year One", "terseLabel": "Year 1" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the seventh year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Seven", "terseLabel": "Year 7" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the sixth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Six", "terseLabel": "Year 6" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the tenth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Ten", "terseLabel": "Year 10" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the third year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Three", "terseLabel": "Year 3" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Percentage of average annual payout, after reinsurance, in the second year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Historical Claims Duration, Year Two", "terseLabel": "Year 2" } } }, "localname": "ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimDurationAndPayoutTableDetails" ], "xbrltype": "percentItemType" }, "us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet": { "auth_ref": [ "r763", "r765" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.", "label": "Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net", "terseLabel": "Incurred but not reported claims" } } }, "localname": "ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet": { "auth_ref": [ "r759" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails": { "order": 1.0, "parentTag": "us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.", "label": "Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net", "terseLabel": "Net incurred claims" } } }, "localname": "ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet": { "auth_ref": [ "r761", "r762" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.", "label": "Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net", "terseLabel": "Net outstanding liabilities for unpaid claims", "totalLabel": "Total outstanding liabilities for unpaid claims net of reinsurance" } } }, "localname": "ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented": { "auth_ref": [ "r761" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails": { "order": 3.0, "parentTag": "us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts for accident years not separately presented in claim development information. Excludes unallocated claim adjustment expense.", "label": "Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented", "terseLabel": "Liability for unpaid claims net, not separately presented" } } }, "localname": "ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims": { "auth_ref": [ "r764" ], "lang": { "en-US": { "role": { "documentation": "Cumulative number of reported claims for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Number of Reported Claims", "terseLabel": "Cumulative number of reported claims" } } }, "localname": "ShortdurationInsuranceContractsNumberOfReportedClaims", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesClaimsDevelopmentTablesDetails" ], "xbrltype": "integerItemType" }, "us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]" } } }, "localname": "ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable": { "auth_ref": [ "r762" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of information about the reconciliation of claims development to the liability for unpaid claims and claim adjustment expense for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table]" } } }, "localname": "ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesReconciliationOfUnpaidClaimsToLiabilityForUnpaidClaimsTableDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock": { "auth_ref": [ "r762" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure for the reconciliation of claims development to the liability for unpaid claims and claim adjustment expense for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block]", "terseLabel": "Reconciliation of unpaid claims to liability for unpaid claims (Table)" } } }, "localname": "ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock": { "auth_ref": [ "r766" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure of average annual percentage payout of incurred claims by age, after reinsurance, for short-duration insurance contracts.", "label": "Short-duration Insurance Contracts, Schedule of Historical Claims Duration [Table Text Block]", "terseLabel": "Claim Duration and Payout (Table)" } } }, "localname": "ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_SingleStockFutureMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "A standardized contract, traded on a futures exchange, to buy or sell a certain stock, at a specified future date in the future, at a certain price.", "label": "Single Stock Future [Member]", "terseLabel": "Equity futures" } } }, "localname": "SingleStockFutureMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_SovereignDebtMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Debt securities that are issued or guaranteed by a national government.", "label": "Sovereign Debt [Member]", "terseLabel": "Sovereign" } } }, "localname": "SovereignDebtMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "us-gaap_StateAndLocalJurisdictionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Designated tax department of a state or local government entitled to levy and collect income taxes from the entity.", "label": "State And Local Jurisdiction [Member]", "terseLabel": "State" } } }, "localname": "StateAndLocalJurisdictionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "domainItemType" }, "us-gaap_StatementBusinessSegmentsAxis": { "auth_ref": [ "r5", "r181", "r290", "r310", "r313", "r314", "r767" ], "lang": { "en-US": { "role": { "documentation": "Information by business segments.", "label": "Segments [Axis]" } } }, "localname": "StatementBusinessSegmentsAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsChangesInGoodwillDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails", "http://principal.com/role/DisclosureSegmentInformationDepreciationAndAmortizationExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationIncomeTaxExpenseBySegmentDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentAssetsToConsolidatedDetails", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "us-gaap_StatementEquityComponentsAxis": { "auth_ref": [ "r47", "r347" ], "lang": { "en-US": { "role": { "documentation": "Information by component of equity.", "label": "Equity Components [Axis]" } } }, "localname": "StatementEquityComponentsAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "stringItemType" }, "us-gaap_StatementLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Statement [Line Items]", "terseLabel": "Statement [Line Items]", "verboseLabel": "Quarterly results of operations" } } }, "localname": "StatementLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "stringItemType" }, "us-gaap_StatementOfCashFlowsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Consolidated Statements of Cash Flows" } } }, "localname": "StatementOfCashFlowsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_StatementOfFinancialPositionAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Consolidated Statements of Financial Position" } } }, "localname": "StatementOfFinancialPositionAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Consolidated Statements of Comprehensive Income" } } }, "localname": "StatementOfIncomeAndComprehensiveIncomeAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_StatementOfStockholdersEquityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Consolidated Statements of Stockholders' Equity" } } }, "localname": "StatementOfStockholdersEquityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_StatementTable": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Schedule reflecting a Statement of Income, Statement of Cash Flows, Statement of Financial Position, Statement of Shareholders' Equity and Other Comprehensive Income, or other statement as needed.", "label": "Statement [Table]" } } }, "localname": "StatementTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails", "http://principal.com/role/DisclosureInsuranceLiabilitiesTables", "http://principal.com/role/DisclosureStockholdersEquityOtherComprehensiveIncomeLossDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "stringItemType" }, "us-gaap_StatutoryAccountingPracticesLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Statutory Accounting Practices [Line Items]", "terseLabel": "Dividend Limitations" } } }, "localname": "StatutoryAccountingPracticesLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_StatutoryAccountingPracticesPermittedPracticeAmount": { "auth_ref": [ "r782" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of each item listed to reconcile the differences as of the balance sheet date resulting from applying state permitted statutory accounting practices rather than statutory accounting practices permitted by National Association of Insurance Commissioners.", "label": "Statutory Accounting Practices, Permitted Practice, Amount", "verboseLabel": "Impact of permitted practices on statutory surplus" } } }, "localname": "StatutoryAccountingPracticesPermittedPracticeAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_StatutoryAccountingPracticesPrescribedPracticeAmount": { "auth_ref": [ "r782" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount as of the balance sheet date of each item listed to reconcile the differences resulting from applying state prescribed statutory accounting practices rather than statutory accounting practices prescribed by National Association of Insurance Commissioners.", "label": "Statutory Accounting Practices, Prescribed Practice, Amount", "verboseLabel": "Impact of prescribed practices on statutory surplus" } } }, "localname": "StatutoryAccountingPracticesPrescribedPracticeAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval": { "auth_ref": [ "r134" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of dividends that can be declared or paid without approval of regulatory agency.", "label": "Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval", "terseLabel": "Dividends that can be paid in upcoming calendar year without exceeding statutory limitation" } } }, "localname": "StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance": { "auth_ref": [ "r707", "r780" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.", "label": "Statutory Accounting Practices, Statutory Capital and Surplus, Balance", "terseLabel": "Statutory capital and surplus" } } }, "localname": "StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount": { "auth_ref": [ "r707" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of net income for the period determined using accounting principles prescribed or permitted by insurance regulators.", "label": "Statutory Accounting Practices, Statutory Net Income Amount", "terseLabel": "Statutory net income" } } }, "localname": "StatutoryAccountingPracticesStatutoryNetIncomeAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_StatutoryAccountingPracticesTable": { "auth_ref": [ "r723", "r781", "r783", "r784", "r785", "r786" ], "lang": { "en-US": { "role": { "documentation": "Detail by state, country, or other jurisdiction of domicile in which financial statements are filed reflecting statutory capital and surplus, net income and the differences between financial reports which are in conformity with generally accepted accounting principles and the statutory financial statements which also use state permitted or prescribed accounting practices.", "label": "Statutory Accounting Practices [Table]" } } }, "localname": "StatutoryAccountingPracticesTable", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityDividendLimitationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans": { "auth_ref": [ "r25", "r26", "r347", "r354" ], "lang": { "en-US": { "role": { "documentation": "Number of shares issued during the period as a result of an employee stock purchase plan.", "label": "Stock Issued During Period, Shares, Employee Stock Purchase Plans", "terseLabel": "Share purchases under employee stock purchase plan (in shares)" } } }, "localname": "StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansEmployeeStockPurchasePlanDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_StockIssuedDuringPeriodSharesNewIssues": { "auth_ref": [ "r25", "r26", "r347", "r354" ], "lang": { "en-US": { "role": { "documentation": "Number of new stock issued during the period.", "label": "Stock Issued During Period, Shares, New Issues", "terseLabel": "Shares issued" } } }, "localname": "StockIssuedDuringPeriodSharesNewIssues", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised": { "auth_ref": [ "r25", "r26", "r347", "r354", "r431" ], "lang": { "en-US": { "role": { "documentation": "Number of share options (or share units) exercised during the current period.", "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period", "terseLabel": "Options exercised (in shares)" } } }, "localname": "StockIssuedDuringPeriodSharesStockOptionsExercised", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockBasedCompensationPlansNonqualifiedStockOptionsActivityDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_StockIssuedDuringPeriodValueNewIssues": { "auth_ref": [ "r25", "r26", "r347", "r354" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.", "label": "Stock Issued During Period, Value, New Issues", "terseLabel": "Common stock issued" } } }, "localname": "StockIssuedDuringPeriodValueNewIssues", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_StockOptionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Contracts conveying rights, but not obligations, to buy or sell a specific quantity of stock at a specified price during a specified period (an American option) or at a specified date (a European option).", "label": "Stock Option [Member]", "terseLabel": "Equity options" } } }, "localname": "StockOptionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_StockholdersEquity": { "auth_ref": [ "r26", "r30", "r31", "r216" ], "calculation": { "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 2.0, "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 1.0, "parentTag": "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.", "label": "Stockholders' Equity Attributable to Parent", "periodEndLabel": "Balances", "periodStartLabel": "Balances", "totalLabel": "Total stockholders' equity attributable to Principal Financial Group, Inc." } } }, "localname": "StockholdersEquity", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest": { "auth_ref": [ "r511", "r512", "r528" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 3.0, "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity", "weight": 1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.", "label": "Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest", "periodEndLabel": "Balances", "periodStartLabel": "Balances", "totalLabel": "Total stockholders' equity" } } }, "localname": "StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]", "terseLabel": "Stockholders' equity" } } }, "localname": "StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "stringItemType" }, "us-gaap_StockholdersEquityNoteAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Stockholders' Equity" } } }, "localname": "StockholdersEquityNoteAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "xbrltype": "stringItemType" }, "us-gaap_StockholdersEquityNoteDisclosureTextBlock": { "auth_ref": [ "r358" ], "lang": { "en-US": { "role": { "documentation": "The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.", "label": "Stockholders' Equity Note Disclosure [Text Block]", "terseLabel": "Stockholders' Equity" } } }, "localname": "StockholdersEquityNoteDisclosureTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquity" ], "xbrltype": "textBlockItemType" }, "us-gaap_SubleaseIncome": { "auth_ref": [ "r640", "r646" ], "calculation": { "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails": { "order": 5.0, "parentTag": "us-gaap_LeaseCost", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of sublease income excluding finance and operating lease expense.", "label": "Sublease Income", "negatedLabel": "Sublease income" } } }, "localname": "SubleaseIncome", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureContingenciesGuaranteesIndemnificationsAndLeasesLeasesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SubsegmentsAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by business subsegments.", "label": "Subsegments [Axis]" } } }, "localname": "SubsegmentsAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SubsegmentsDomain": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Divisions of a component of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.", "label": "Subsegments [Domain]", "terseLabel": "Subsegments [Domain]" } } }, "localname": "SubsegmentsDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesContractholderAndPolicyholderLiabilitiesDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationBySegmentDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersDisaggregationWithinSegmentsDetails", "http://principal.com/role/DisclosureRevenuesFromContractsWithCustomersTables", "http://principal.com/role/DisclosureSegmentInformationReconciliationOfSegmentOperatingRevenuesAndEarningsToConsolidatedDetails" ], "xbrltype": "domainItemType" }, "us-gaap_SummaryOfCashFlowHedgeActivityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Summary of Cash Flow Hedge Activity [Abstract]", "terseLabel": "Cash Flow Hedges" } } }, "localname": "SummaryOfCashFlowHedgeActivityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCashFlowHedgesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SummaryOfDerivativeInstrumentsImpactOnResultsOfOperationsAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Summary of Derivative Instruments Impact on Results of Operations [Abstract]", "terseLabel": "Gains (losses) recognized for hedging relationships" } } }, "localname": "SummaryOfDerivativeInstrumentsImpactOnResultsOfOperationsAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsEffectOfHedgesOnConsolidatedStatementsOfOperationsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SummaryOfFairValueHedgeActivityAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Summary of Fair Value Hedge Activity [Abstract]", "terseLabel": "Fair Value Hedges" } } }, "localname": "SummaryOfFairValueHedgeActivityAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsFairValueHedgesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_SummaryOfIncomeTaxContingenciesTextBlock": { "auth_ref": [ "r468", "r477", "r479" ], "lang": { "en-US": { "role": { "documentation": "Tabular disclosure for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities and other income tax contingencies. Includes, but is not limited to, interest and penalties, reconciliation of unrecognized tax benefits, unrecognized tax benefits that would affect the effective tax rate, tax years that remain subject to examination by tax jurisdictions, and information about positions for which it is reasonably possible that amounts unrecognized will significantly change within 12 months.", "label": "Summary of Income Tax Contingencies [Table Text Block]", "terseLabel": "Changes in Unrecognized Tax Benefits (Table)" } } }, "localname": "SummaryOfIncomeTaxContingenciesTextBlock", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesTables" ], "xbrltype": "textBlockItemType" }, "us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount": { "auth_ref": [ "r832" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment held by insurance company, excluding investment in related party.", "label": "Summary of Investments, Other than Investments in Related Parties, Carrying Amount", "terseLabel": "Amount as shown in the Consolidated Statement of Financial Position" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost": { "auth_ref": [ "r830" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Cost of investment held by insurance company, excluding investment in related party.", "label": "Summary of Investments, Other than Investments in Related Parties, Cost", "terseLabel": "Cost" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue": { "auth_ref": [ "r831" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Fair value of investment held by insurance company, excluding investment in related party.", "label": "Summary of Investments, Other than Investments in Related Parties, Fair Value", "terseLabel": "Value" } } }, "localname": "SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SupplementalCashFlowInformationAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Supplemental Cash Flow Information [Abstract]", "terseLabel": "Supplemental information:", "verboseLabel": "Supplemental Disclosures of Non-Cash Investing Activity" } } }, "localname": "SupplementalCashFlowInformationAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "stringItemType" }, "us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense": { "auth_ref": [ "r755" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 1.0, "parentTag": "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of expense for claims incurred in the current reporting period and related claims settlement costs.", "label": "Current Year Claims and Claims Adjustment Expense", "terseLabel": "Incurred: Current year" } } }, "localname": "SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense": { "auth_ref": [ "r755" ], "calculation": { "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails": { "order": 2.0, "parentTag": "us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.", "label": "Prior Year Claims and Claims Adjustment Expense", "terseLabel": "Incurred: Prior years" } } }, "localname": "SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureInsuranceLiabilitiesLiabilityForUnpaidClaimsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense": { "auth_ref": [ "r738" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of operating expense classified as other, disclosed in supplementary insurance information.", "label": "Supplementary Insurance Information, Other Operating Expense", "terseLabel": "Other operating expenses" } } }, "localname": "SupplementaryInsuranceInformationOtherOperatingExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiiSupplementaryInsuranceInformationDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_SwaptionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Option contract giving the holder the right to enter into a swap.", "label": "Swaption [Member]", "terseLabel": "Swaptions" } } }, "localname": "SwaptionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsNotionalAmountsAndCreditExposureDetails" ], "xbrltype": "domainItemType" }, "us-gaap_TaxCutsAndJobsActOf2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalIncomeTaxExpense": { "auth_ref": [ "r497" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of reasonable estimate for income tax expense for which accounting for tax effect from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated is incomplete pursuant to Tax Cuts and Jobs Act.", "label": "Tax Cuts and Jobs Act, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense", "verboseLabel": "One-time deemed repatriation tax, provisional amount" } } }, "localname": "TaxCutsAndJobsActOf2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalIncomeTaxExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_TaxCutsAndJobsActOf2017MeasurementPeriodAdjustmentIncomeTaxExpenseBenefit": { "auth_ref": [ "r498" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of income tax expense (benefit) for measurement period adjustment from accounting for tax effect pursuant to Tax Cuts and Jobs Act.", "label": "Tax Cuts and Jobs Act, Measurement Period Adjustment, Income Tax Expense (Benefit)", "verboseLabel": "Adjustment to one-time deemed repatriation tax" } } }, "localname": "TaxCutsAndJobsActOf2017MeasurementPeriodAdjustmentIncomeTaxExpenseBenefit", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsIncomeTaxExpense": { "auth_ref": [ "r492" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of income tax expense from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act.", "label": "Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Income Tax Expense", "terseLabel": "One-time deemed repatriation tax, final determination amount" } } }, "localname": "TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsIncomeTaxExpense", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesDeferredIncomeTaxesAndOtherDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_TechnologyBasedIntangibleAssetsMember": { "auth_ref": [ "r506" ], "lang": { "en-US": { "role": { "documentation": "Technology-based intangible assets, including, but not limited to, patented technology, unpatented technology, and developed technology rights.", "label": "Technology Based Intangible Assets [Member]", "terseLabel": "Technology" } } }, "localname": "TechnologyBasedIntangibleAssetsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsGoodwillAcquiredDetails" ], "xbrltype": "domainItemType" }, "us-gaap_TradingSecuritiesDebt": { "auth_ref": [ "r217", "r218" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails": { "order": 2.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails": { "order": 2.0, "parentTag": "pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets", "weight": 1.0 }, "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails": { "order": 2.0, "parentTag": "us-gaap_Assets", "weight": 1.0 }, "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 2.0, "parentTag": "us-gaap_Investments", "weight": 1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).", "label": "Trading Securities, Debt", "terseLabel": "Fixed maturities, trading", "verboseLabel": "Fixed maturities, trading" } } }, "localname": "TradingSecuritiesDebt", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain": { "auth_ref": [ "r655" ], "lang": { "en-US": { "role": { "documentation": "Instrument or contract that imposes a contractual obligation to deliver cash or another financial instrument or to exchange other financial instruments on potentially unfavorable terms and conveys a contractual right to receive cash or another financial instrument or to exchange other financial instruments on potentially favorable terms.", "label": "Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain]", "terseLabel": "Fair Value Option Grouping" } } }, "localname": "TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDebtContingentFundingAgreementsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsFairValueOptionOnConsolidatedViesAndEquityMethodInvestmentsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_TreasuryStockMember": { "auth_ref": [ "r46", "r356" ], "lang": { "en-US": { "role": { "documentation": "Shares of an entity that have been repurchased by the entity. This stock has no voting rights and receives no dividends. Note that treasury stock may be recorded at its total cost or separately as par (or stated) value and additional paid in capital. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer.", "label": "Treasury Stock [Member]", "terseLabel": "Treasury stock" } } }, "localname": "TreasuryStockMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_TreasuryStockShares": { "auth_ref": [ "r46", "r356" ], "lang": { "en-US": { "role": { "documentation": "Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.", "label": "Treasury Stock, Shares", "terseLabel": "Treasury stock (in shares)" } } }, "localname": "TreasuryStockShares", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionParentheticalDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "sharesItemType" }, "us-gaap_TreasuryStockSharesAcquired": { "auth_ref": [ "r26", "r347", "r354" ], "lang": { "en-US": { "role": { "documentation": "Number of shares that have been repurchased during the period and are being held in treasury.", "label": "Treasury Stock, Shares, Acquired", "negatedLabel": "Treasury stock acquired" } } }, "localname": "TreasuryStockSharesAcquired", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureStockholdersEquityCommonStockDividendsAndReconciliationOfOutstandingCommonSharesDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_TreasuryStockValue": { "auth_ref": [ "r46", "r356", "r357" ], "calculation": { "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition": { "order": 5.0, "parentTag": "us-gaap_StockholdersEquity", "weight": -1.0 } }, "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury.", "label": "Treasury Stock, Value", "negatedLabel": "Treasury stock, at cost (202.7 million and 197.2 million shares in 2019 and 2018)", "negatedTerseLabel": "Treasury stock, at cost" } } }, "localname": "TreasuryStockValue", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfFinancialPositionDetails", "http://principal.com/role/DisclosureScheduleIiCondensedFinancialInformationOfRegistrantParentOnlyStatementsOfFinancialPositionDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition" ], "xbrltype": "monetaryItemType" }, "us-gaap_TreasuryStockValueAcquiredCostMethod": { "auth_ref": [ "r347", "r354", "r356" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.", "label": "Treasury Stock, Value, Acquired, Cost Method", "negatedLabel": "Treasury stock acquired, common" } } }, "localname": "TreasuryStockValueAcquiredCostMethod", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "monetaryItemType" }, "us-gaap_TypeOfAdoptionMember": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Adoption and early adoption of sources of change to generally accepted accounting principles (GAAP) in the United States. The FASB released the FASB Accounting Standards Codification as the authoritative source of literature effective for interim and annual periods ending after September 15, 2009. As part of the Codification process, the FASB issues Accounting Standards Updates to amend the Codification but otherwise the Accounting Standards Updates are not authoritative in their own right. All previous accounting standards (such as FASB Statements of Financial Accounting Standards, FASB Interpretations, FASB Staff Positions, Emerging Issues Task Force Consensuses, other pronouncements of the FASB or other designated bodies, or other forms of GAAP are considered accounting pronouncements) were superseded upon the adoption of the Codification. For an interim period, references to the superseded standards are included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.", "label": "Type Of Adoption [Member]", "terseLabel": "Type of Adoption [Domain]" } } }, "localname": "TypeOfAdoptionMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesRecentAccountingPronouncementsDetails", "http://principal.com/role/DisclosureStockholdersEquityAociAndNoncontrollingInterestDetails", "http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity" ], "xbrltype": "domainItemType" }, "us-gaap_USStatesAndPoliticalSubdivisionsMember": { "auth_ref": [ "r385", "r799" ], "lang": { "en-US": { "role": { "documentation": "Bonds or similar securities issued by state, city, or local US governments or the agencies operated by state, city, or local governments. Debt securities issued by state governments may include bond issuances of US state authorities including, for example, but not limited to, housing authorities, dormitory authorities, and general obligations while debt securities issued by political subdivisions of US states would include, for example, debt issuances by county, borough, city, or municipal governments.", "label": "U S States And Political Subdivisions [Member]", "terseLabel": "States and political subdivisions" } } }, "localname": "USStatesAndPoliticalSubdivisionsMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_USTreasuryAndGovernmentMember": { "auth_ref": [ "r385", "r666", "r799" ], "lang": { "en-US": { "role": { "documentation": "This category includes investments in debt securities issued by the United States Department of the Treasury, US Government Agencies and US Government-sponsored Enterprises. Such securities may include treasury bills (short-term maturities - one year or less), treasury notes (intermediate term maturities - two to ten years), and treasury bonds (long-term maturities - ten to thirty years), debt securities issued by the Government National Mortgage Association (Ginnie Mae) and debt securities issued by the Federal National Mortgage Association (Fannie Mae) or the Federal Home Loan Mortgage Corporation (Freddie Mac).", "label": "U S Treasury And Government [Member]", "terseLabel": "U.S. government and agencies" } } }, "localname": "USTreasuryAndGovernmentMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEmployeeAndAgentBenefitsFairValueOfPlanAssetsDetails", "http://principal.com/role/DisclosureFairValueMeasurementsAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails", "http://principal.com/role/DisclosureFairValueMeasurementsTransfersDetails", "http://principal.com/role/DisclosureInvestmentsFixedMaturitiesAndEquitySecuritiesDetails", "http://principal.com/role/DisclosureInvestmentsGrossUnrealizedLossesForFixedMaturitiesDetails", "http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails" ], "xbrltype": "domainItemType" }, "us-gaap_UnderlyingAssetClassAxis": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Information by underlying asset class.", "label": "Underlying Asset Class [Axis]" } } }, "localname": "UnderlyingAssetClassAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "stringItemType" }, "us-gaap_UnderlyingAssetClassDomain": { "auth_ref": [ "r569" ], "lang": { "en-US": { "role": { "documentation": "Major types of referenced/underlying asset classes (for example, corporate debt, sovereign debt, and structured finance).", "label": "Underlying Asset Class [Domain]", "terseLabel": "Underlying Asset Class [Domain]" } } }, "localname": "UnderlyingAssetClassDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureDerivativeFinancialInstrumentsCreditDerivativesSoldDetails" ], "xbrltype": "domainItemType" }, "us-gaap_UnrecognizedTaxBenefits": { "auth_ref": [ "r461", "r472" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of unrecognized tax benefits.", "label": "Unrecognized Tax Benefits", "periodEndLabel": "Ending balance, Unrecognized tax benefits", "periodStartLabel": "Beginning balance, Unrecognized tax benefits" } } }, "localname": "UnrecognizedTaxBenefits", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions": { "auth_ref": [ "r474" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.", "label": "Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions", "negatedLabel": "Reductions for tax positions related to the current year" } } }, "localname": "UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions": { "auth_ref": [ "r473" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.", "label": "Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions", "negatedLabel": "Reductions for tax positions of prior years" } } }, "localname": "UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities": { "auth_ref": [ "r475" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.", "label": "Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities", "negatedLabel": "Settlements" } } }, "localname": "UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued": { "auth_ref": [ "r467" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.", "label": "Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued", "terseLabel": "Accumulated pre-tax interest and penalties related to unrecognized tax benefits" } } }, "localname": "UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions": { "auth_ref": [ "r474" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.", "label": "Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions", "terseLabel": "Additions based on tax positions related to the current year" } } }, "localname": "UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions": { "auth_ref": [ "r473" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.", "label": "Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions", "terseLabel": "Additions for tax positions of prior years" } } }, "localname": "UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate": { "auth_ref": [ "r476" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.", "label": "Unrecognized Tax Benefits that Would Impact Effective Tax Rate", "terseLabel": "Amount of unrecognized tax benefits that would reduce the effective income tax rate, if recognized" } } }, "localname": "UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitsDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_UseOfEstimates": { "auth_ref": [ "r168", "r169", "r170", "r171", "r172", "r173", "r174" ], "lang": { "en-US": { "role": { "documentation": "Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.", "label": "Use of Estimates, Policy [Policy Text Block]", "verboseLabel": "Use of Estimates in the Preparation of Financial Statements" } } }, "localname": "UseOfEstimates", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies" ], "xbrltype": "textBlockItemType" }, "us-gaap_ValuationTechniqueAxis": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Information by valuation approach and technique.", "label": "Valuation Technique [Axis]" } } }, "localname": "ValuationTechniqueAxis", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "stringItemType" }, "us-gaap_ValuationTechniqueDiscountedCashFlowMember": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Valuation technique calculating present value of future cash flows.", "label": "Valuation Technique Discounted Cash Flow [Member]", "terseLabel": "Discounted cash flow" } } }, "localname": "ValuationTechniqueDiscountedCashFlowMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_ValuationTechniqueDomain": { "auth_ref": [ "r589" ], "lang": { "en-US": { "role": { "documentation": "Valuation approach and technique.", "label": "Valuation Technique [Domain]", "terseLabel": "Valuation Technique [Domain]" } } }, "localname": "ValuationTechniqueDomain", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureFairValueMeasurementsQuantitativeInformationForLevel3MeasurementsDetails" ], "xbrltype": "domainItemType" }, "us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssetsAndLiabilitiesAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]", "terseLabel": "Carrying amounts of consolidated VIE assets and liabilities" } } }, "localname": "VariableInterestEntityConsolidatedCarryingAmountAssetsAndLiabilitiesAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount": { "auth_ref": [ "r526", "r527" ], "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).", "label": "Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount", "terseLabel": "Maximum exposure to loss" } } }, "localname": "VariableInterestEntityEntityMaximumLossExposureAmount", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_VariableInterestEntityLineItems": { "auth_ref": [], "lang": { "en-US": { "role": { "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.", "label": "Variable Interest Entity [Line Items]", "terseLabel": "Consolidated Variable Interest Entity disclosures" } } }, "localname": "VariableInterestEntityLineItems", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails" ], "xbrltype": "stringItemType" }, "us-gaap_VariableInterestEntityNonconsolidatedCarryingAmountAssets": { "auth_ref": [ "r525" ], "crdr": "debit", "lang": { "en-US": { "role": { "documentation": "Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.", "label": "Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets", "terseLabel": "Asset carrying value" } } }, "localname": "VariableInterestEntityNonconsolidatedCarryingAmountAssets", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesUnconsolidatedViesDetails" ], "xbrltype": "monetaryItemType" }, "us-gaap_VariableInterestEntityPrimaryBeneficiaryMember": { "auth_ref": [ "r524" ], "lang": { "en-US": { "role": { "documentation": "Variable Interest Entities (VIE) in which the entity has a controlling financial interest (as defined) and of which it is therefore the primary beneficiary. A controlling financial interest is determined based on both: (a) the entity's power to direct activities of the VIE that most significantly impact the VIE's economic performance and (b) the entity's obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. VIEs of which the entity is the primary beneficiary are included in the consolidated financial statements of the entity.", "label": "Variable Interest Entity Primary Beneficiary [Member]", "terseLabel": "Aggregate consolidated variable interest entities" } } }, "localname": "VariableInterestEntityPrimaryBeneficiaryMember", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureVariableInterestEntitiesConsolidatedViesDetails", "http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical" ], "xbrltype": "domainItemType" }, "us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]", "terseLabel": "Dilutive effects:" } } }, "localname": "WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "stringItemType" }, "us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding": { "auth_ref": [ "r155", "r160" ], "calculation": { "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": null, "parentTag": null, "root": true, "weight": null } }, "lang": { "en-US": { "role": { "documentation": "The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.", "label": "Weighted Average Number of Shares Outstanding, Diluted", "totalLabel": "Diluted" } } }, "localname": "WeightedAverageNumberOfDilutedSharesOutstanding", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract": { "auth_ref": [], "lang": { "en-US": { "role": { "label": "Weighted Average Number of Shares Outstanding, Diluted [Abstract]", "terseLabel": "Weighted-average shares outstanding:" } } }, "localname": "WeightedAverageNumberOfSharesOutstandingAbstract", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "stringItemType" }, "us-gaap_WeightedAverageNumberOfSharesOutstandingBasic": { "auth_ref": [ "r153", "r160" ], "calculation": { "http://principal.com/role/DisclosureEarningsPerCommonShareDetails": { "order": 1.0, "parentTag": "us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding", "weight": 1.0 } }, "lang": { "en-US": { "role": { "documentation": "Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.", "label": "Weighted Average Number of Shares Outstanding, Basic", "terseLabel": "Basic" } } }, "localname": "WeightedAverageNumberOfSharesOutstandingBasic", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureEarningsPerCommonShareDetails" ], "xbrltype": "sharesItemType" }, "us-gaap_WithdrawalFromContractHoldersFunds": { "auth_ref": [ "r109" ], "calculation": { "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails": { "order": 13.0, "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities", "weight": -1.0 } }, "crdr": "credit", "lang": { "en-US": { "role": { "documentation": "The cash outflow for a segregated fund account during the period.", "label": "Withdrawal from Contract Holders Funds", "negatedLabel": "Investment contract withdrawals" } } }, "localname": "WithdrawalFromContractHoldersFunds", "nsuri": "http://fasb.org/us-gaap/2019-01-31", "presentation": [ "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationShelfRegistrationGuarantorStatementsOfCashFlowsDetails", "http://principal.com/role/StatementConsolidatedStatementsOfCashFlows" ], "xbrltype": "monetaryItemType" } }, "unitCount": 8 } }, "std_ref": { "r0": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222160&loc=d3e957-107759" }, "r1": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222160&loc=SL51721523-107759" }, "r10": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(27)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r100": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585" }, "r101": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585" }, "r102": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585" }, "r103": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585" }, "r104": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585" }, "r105": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585" }, "r106": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585" }, "r107": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585" }, "r108": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585" }, "r109": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585" }, "r11": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(1))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r110": { "Name": "Accounting Standards Codification", "Paragraph": "17", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3367-108585" }, "r111": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3000-108585" }, "r112": { "Name": "Accounting Standards Codification", "Paragraph": "23", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3505-108585" }, "r113": { "Name": "Accounting Standards Codification", "Paragraph": "24", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3521-108585" }, "r114": { "Name": "Accounting Standards Codification", "Paragraph": "25", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585" }, "r115": { "Name": "Accounting Standards Codification", "Paragraph": "25", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585" }, "r116": { "Name": "Accounting Standards Codification", "Paragraph": "25", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585" }, "r117": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585" }, "r118": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585" }, "r119": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585" }, "r12": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(12))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r120": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3044-108585" }, "r121": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3095-108585" }, "r122": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4273-108586" }, "r123": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586" }, "r124": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586" }, "r125": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586" }, "r126": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586" }, "r127": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586" }, "r128": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790" }, "r129": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08(d))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r13": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(13))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r130": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08(g))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r131": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08(h))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r132": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08(m)(1)(iii))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r133": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(d),(e))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r134": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(e))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r135": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(e),(f))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r136": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(h)(1)(i))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r137": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(h)(2))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r138": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(h))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r139": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(k)(1))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r14": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(14))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r140": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.(n))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r141": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.4-08.g)", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690" }, "r142": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.12-04(a))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690" }, "r143": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.12-04)", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690" }, "r144": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.12-04.(a))", "Topic": "235", "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690" }, "r145": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "235", "URI": "http://asc.fasb.org/topic&trid=2122369" }, "r146": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794" }, "r147": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794" }, "r148": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794" }, "r149": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22644-107794" }, "r15": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(17))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r150": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22658-107794" }, "r151": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "250", "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22663-107794" }, "r152": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "250", "URI": "http://asc.fasb.org/topic&trid=2122394" }, "r153": { "Name": "Accounting Standards Codification", "Paragraph": "10", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1448-109256" }, "r154": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1377-109256" }, "r155": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1505-109256" }, "r156": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1252-109256" }, "r157": { "Name": "Accounting Standards Codification", "Paragraph": "28A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1500-109256" }, "r158": { "Name": "Accounting Standards Codification", "Paragraph": "60B", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=SL5780133-109256" }, "r159": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1337-109256" }, "r16": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(19)(a))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r160": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257" }, "r161": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257" }, "r162": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257" }, "r163": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3630-109257" }, "r164": { "Name": "Accounting Standards Codification", "Paragraph": "52", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "260", "URI": "http://asc.fasb.org/extlink&oid=117327953&loc=d3e4984-109258" }, "r165": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "260", "URI": "http://asc.fasb.org/topic&trid=2144383" }, "r166": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "270", "URI": "http://asc.fasb.org/extlink&oid=118952077&loc=d3e1280-108306" }, "r167": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "270", "URI": "http://asc.fasb.org/topic&trid=2126967" }, "r168": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592" }, "r169": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592" }, "r17": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(19))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r170": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6161-108592" }, "r171": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6191-108592" }, "r172": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6061-108592" }, "r173": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6132-108592" }, "r174": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "275", "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6143-108592" }, "r175": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "275", "URI": "http://asc.fasb.org/topic&trid=2134479" }, "r176": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r177": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r178": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r179": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r18": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(2))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r180": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(h)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r181": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599" }, "r182": { "Name": "Accounting Standards Codification", "Paragraph": "25", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599" }, "r183": { "Name": "Accounting Standards Codification", "Paragraph": "30", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8906-108599" }, "r184": { "Name": "Accounting Standards Codification", "Paragraph": "30", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8906-108599" }, "r185": { "Name": "Accounting Standards Codification", "Paragraph": "30", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8906-108599" }, "r186": { "Name": "Accounting Standards Codification", "Paragraph": "31", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8924-108599" }, "r187": { "Name": "Accounting Standards Codification", "Paragraph": "32", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599" }, "r188": { "Name": "Accounting Standards Codification", "Paragraph": "32", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599" }, "r189": { "Name": "Accounting Standards Codification", "Paragraph": "32", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599" }, "r19": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(20))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r190": { "Name": "Accounting Standards Codification", "Paragraph": "40", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9031-108599" }, "r191": { "Name": "Accounting Standards Codification", "Paragraph": "41", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "280", "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9038-108599" }, "r192": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "280", "URI": "http://asc.fasb.org/topic&trid=2134510" }, "r193": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522" }, "r194": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r195": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r196": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(3)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r197": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(4)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r198": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r199": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r2": { "Name": "Accounting Standards Codification", "Paragraph": "3B", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222160&loc=SL51721525-107759" }, "r20": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(22))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r200": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r201": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(h)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r202": { "Name": "Accounting Standards Codification", "Paragraph": "11B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524" }, "r203": { "Name": "Accounting Standards Codification", "Paragraph": "14A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524" }, "r204": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(3)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524" }, "r205": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(4)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524" }, "r206": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524" }, "r207": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524" }, "r208": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524" }, "r209": { "Name": "Accounting Standards Codification", "Paragraph": "17", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524" }, "r21": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(24))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r210": { "Name": "Accounting Standards Codification", "Paragraph": "29", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953659-111524" }, "r211": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5086-111524" }, "r212": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524" }, "r213": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524" }, "r214": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524" }, "r215": { "Name": "Accounting Standards Codification", "Paragraph": "7A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=SL6953401-111524" }, "r216": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 4.E)", "Topic": "310", "URI": "http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707" }, "r217": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562" }, "r218": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562" }, "r219": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118954083&loc=d3e26853-111562" }, "r22": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(26)(a))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r220": { "Name": "Accounting Standards Codification", "Paragraph": "8A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118954083&loc=SL6284422-111562" }, "r221": { "Name": "Accounting Standards Codification", "Paragraph": "10", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27405-111563" }, "r222": { "Name": "Accounting Standards Codification", "Paragraph": "1B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6283291-111563" }, "r223": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563" }, "r224": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(aa)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563" }, "r225": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563" }, "r226": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563" }, "r227": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563" }, "r228": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563" }, "r229": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563" }, "r23": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(26)(b))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r230": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563" }, "r231": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563" }, "r232": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563" }, "r233": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27337-111563" }, "r234": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27340-111563" }, "r235": { "Name": "Accounting Standards Codification", "Paragraph": "8B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563" }, "r236": { "Name": "Accounting Standards Codification", "Paragraph": "8B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563" }, "r237": { "Name": "Accounting Standards Codification", "Paragraph": "8B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563" }, "r238": { "Name": "Accounting Standards Codification", "Paragraph": "8B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563" }, "r239": { "Name": "Accounting Standards Codification", "Paragraph": "8B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563" }, "r24": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(27))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r240": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563" }, "r241": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "320", "URI": "http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563" }, "r242": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "320", "URI": "http://asc.fasb.org/topic&trid=2196928" }, "r243": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "321", "URI": "http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714" }, "r244": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "05", "SubTopic": "10", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=75018788&loc=d3e30768-111565" }, "r245": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570" }, "r246": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=109237563&loc=d3e33775-111570" }, "r247": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=114001798&loc=d3e33912-111571" }, "r248": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571" }, "r249": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(3)", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571" }, "r25": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(28))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r250": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(b)", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571" }, "r251": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "323", "URI": "http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571" }, "r252": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446" }, "r253": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919244-210447" }, "r254": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(i)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919244-210447" }, "r255": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919244-210447" }, "r256": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447" }, "r257": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447" }, "r258": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(e)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447" }, "r259": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(f)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447" }, "r26": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(29))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r260": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447" }, "r261": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919253-210447" }, "r262": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447" }, "r263": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(c)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447" }, "r264": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447" }, "r265": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919230-210447" }, "r266": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919230-210447" }, "r267": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955255&loc=SL82921842-210448" }, "r268": { "Name": "Accounting Standards Codification", "Paragraph": "79", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955255&loc=SL82922352-210448" }, "r269": { "Name": "Accounting Standards Codification", "Paragraph": "80", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448" }, "r27": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(3))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r270": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454" }, "r271": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455" }, "r272": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(1)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455" }, "r273": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(2)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455" }, "r274": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(b)(3)", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455" }, "r275": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455" }, "r276": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922890-210455" }, "r277": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922895-210455" }, "r278": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118955579&loc=SL82922900-210455" }, "r279": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "55", "SubTopic": "30", "Topic": "326", "URI": "http://asc.fasb.org/extlink&oid=118942371&loc=SL82922954-210456" }, "r28": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(30)(a)(1))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r280": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "340", "URI": "http://asc.fasb.org/extlink&oid=99397363&loc=d3e9420-108338" }, "r281": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "340", "URI": "http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054" }, "r282": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "340", "URI": "http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054" }, "r283": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "340", "URI": "http://asc.fasb.org/extlink&oid=68051541&loc=SL51790836-203054" }, "r284": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266" }, "r285": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975" }, "r286": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267" }, "r287": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267" }, "r288": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(f)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267" }, "r289": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(g)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267" }, "r29": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(30)(a)(3))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r290": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267" }, "r291": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267" }, "r292": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274" }, "r293": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274" }, "r294": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275" }, "r295": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(1)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275" }, "r296": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(d)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275" }, "r297": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275" }, "r298": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "((a)(1),(b))", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r299": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r3": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222160&loc=d3e1012-107759" }, "r30": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(30))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r300": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(1)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r301": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(2)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r302": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)(3)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r303": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(b)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r304": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(d)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275" }, "r305": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(b),(d)", "Topic": "350", "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275" }, "r306": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "350", "URI": "http://asc.fasb.org/topic&trid=2144416" }, "r307": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "360", "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229" }, "r308": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "360", "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229" }, "r309": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "360", "URI": "http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230" }, "r31": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(31))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r310": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "360", "URI": "http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230" }, "r311": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "15", "SubTopic": "30", "Topic": "405", "URI": "http://asc.fasb.org/extlink&oid=99384745&loc=d3e23169-109297" }, "r312": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "405", "URI": "http://asc.fasb.org/extlink&oid=6392405&loc=d3e24119-109301" }, "r313": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "420", "URI": "http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869" }, "r314": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 5.P.4(d))", "Topic": "420", "URI": "http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747" }, "r315": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14326-108349" }, "r316": { "Name": "Accounting Standards Codification", "Paragraph": "10", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14615-108349" }, "r317": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14394-108349" }, "r318": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349" }, "r319": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349" }, "r32": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(32))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r320": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14453-108349" }, "r321": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14472-108349" }, "r322": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14557-108349" }, "r323": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "450", "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14557-108349" }, "r324": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12021-110248" }, "r325": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12053-110248" }, "r326": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248" }, "r327": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(4)", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248" }, "r328": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)(1)", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248" }, "r329": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "460", "URI": "http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248" }, "r33": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02(8))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r330": { "Name": "Accounting Standards Codification", "Paragraph": "12A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=99376301&loc=SL5988623-112600" }, "r331": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601" }, "r332": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=6802200&loc=SL6230698-112601" }, "r333": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(1)", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870" }, "r334": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(2)", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870" }, "r335": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(3)", "Topic": "470", "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870" }, "r336": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "470", "URI": "http://asc.fasb.org/topic&trid=2208564" }, "r337": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(CFRR 211.02)", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764" }, "r338": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764" }, "r339": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(12)(c)", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r34": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.1)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r340": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(16)(c)", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r341": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(3)", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r342": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "14", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r343": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "15", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r344": { "Name": "Accounting Standards Codification", "Paragraph": "3A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "16(c)", "Topic": "480", "URI": "http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764" }, "r345": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=65888546&loc=d3e21300-112643" }, "r346": { "Name": "Accounting Standards Codification", "Paragraph": "10", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21553-112644" }, "r347": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644" }, "r348": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644" }, "r349": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21484-112644" }, "r35": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.12)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r350": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21488-112644" }, "r351": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644" }, "r352": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644" }, "r353": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644" }, "r354": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.3-04)", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770" }, "r355": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770" }, "r356": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655" }, "r357": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "505", "URI": "http://asc.fasb.org/extlink&oid=6405834&loc=d3e23315-112656" }, "r358": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "505", "URI": "http://asc.fasb.org/topic&trid=2208762" }, "r359": { "Name": "Accounting Standards Codification", "Paragraph": "22", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130569-203045" }, "r36": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.17)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r360": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045" }, "r361": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045" }, "r362": { "Name": "Accounting Standards Codification", "Paragraph": "91", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046" }, "r363": { "Name": "Accounting Standards Codification", "Paragraph": "91", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046" }, "r364": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Topic": "606", "URI": "http://asc.fasb.org/extlink&oid=113356391&loc=SL49131195-203048" }, "r365": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "606", "URI": "http://asc.fasb.org/topic&trid=49130388" }, "r366": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "15", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "712", "URI": "http://asc.fasb.org/extlink&oid=6410066&loc=d3e79218-111664" }, "r367": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "15", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "712", "URI": "http://asc.fasb.org/extlink&oid=6410066&loc=d3e79218-111664" }, "r368": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=109237824&loc=d3e1703-114919" }, "r369": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=109237824&loc=d3e1731-114919" }, "r37": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.19(a))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r370": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r371": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(1)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r372": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(2)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r373": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(3)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r374": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(4)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r375": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(6)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r376": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(7)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r377": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r378": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(1)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r379": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(3)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r38": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.19(b))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r380": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(4)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r381": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(5)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r382": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(c)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r383": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)(5)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r384": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)(i)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r385": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)(ii)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r386": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)(iv)(01)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r387": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(e)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r388": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(f)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r389": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(g)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r39": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.19(b),22(b))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r390": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r391": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)(1)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r392": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)(2)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r393": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)(3)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r394": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)(4)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r395": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(h)(5)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r396": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(i)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r397": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(j)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r398": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(k)(1)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r399": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(k)(2)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r4": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760" }, "r40": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.19)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r400": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(k)(3)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r401": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(l)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r402": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(m)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r403": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(n)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r404": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(s)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r405": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920" }, "r406": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2410-114920" }, "r407": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920" }, "r408": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920" }, "r409": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920" }, "r41": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.19-26)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r410": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2439-114920" }, "r411": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r412": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(1)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r413": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(2)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r414": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(3)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r415": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(4)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r416": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)(5)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r417": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920" }, "r418": { "Name": "Accounting Standards Codification", "Paragraph": "17", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921" }, "r419": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "60", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964" }, "r42": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.22(a)(1))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r420": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "70", "Topic": "715", "URI": "http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942" }, "r421": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "715", "URI": "http://asc.fasb.org/topic&trid=2235017" }, "r422": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901" }, "r423": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901" }, "r424": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r425": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r426": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a),(g)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r427": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r428": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)(i)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r429": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)(i)-(ii)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r43": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.22(b))", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r430": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)(iii)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r431": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)(iv)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r432": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r433": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)(i)-(ii)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r434": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)(iii)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r435": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)(iii)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r436": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r437": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r438": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r439": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r44": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.22)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r440": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r441": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r442": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r443": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)(2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r444": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)(2)(i)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r445": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)(2)(ii)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r446": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)(2)(iii)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r447": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)(2)(iv)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r448": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r449": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(h)(1)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r45": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.28,29)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r450": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(h)(1)(i)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r451": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(i)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r452": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901" }, "r453": { "Name": "Accounting Standards Codification", "Paragraph": "2A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=SL79508275-113901" }, "r454": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 14.D.2)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809" }, "r455": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(d)", "Topic": "718", "URI": "http://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929" }, "r456": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "718", "URI": "http://asc.fasb.org/topic&trid=2228938" }, "r457": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "25", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314" }, "r458": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "25", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314" }, "r459": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "25", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314" }, "r46": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.29,30)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r460": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "30", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=109238119&loc=d3e30536-109315" }, "r461": { "Name": "Accounting Standards Codification", "Paragraph": "10B", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=SL37586934-109318" }, "r462": { "Name": "Accounting Standards Codification", "Paragraph": "25", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e32247-109318" }, "r463": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e32280-109318" }, "r464": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e31931-109318" }, "r465": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319" }, "r466": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319" }, "r467": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319" }, "r468": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319" }, "r469": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319" }, "r47": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.29-31)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r470": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319" }, "r471": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(3)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r472": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r473": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r474": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r475": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(3)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r476": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r477": { "Name": "Accounting Standards Codification", "Paragraph": "15A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319" }, "r478": { "Name": "Accounting Standards Codification", "Paragraph": "17", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32809-109319" }, "r479": { "Name": "Accounting Standards Codification", "Paragraph": "19", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32840-109319" }, "r48": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.3,4)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r480": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319" }, "r481": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319" }, "r482": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b),(c)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319" }, "r483": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319" }, "r484": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319" }, "r485": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32847-109319" }, "r486": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319" }, "r487": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319" }, "r488": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319" }, "r489": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319" }, "r49": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-02.31)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682" }, "r490": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319" }, "r491": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319" }, "r492": { "Name": "Accounting Standards Codification", "Paragraph": "9", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319" }, "r493": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=117331771&loc=SL96870463-158277" }, "r494": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=117331771&loc=SL96870463-158277" }, "r495": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB TOPIC 6.I)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817" }, "r496": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 6.I.7)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817" }, "r497": { "Name": "Accounting Standards Codification", "Paragraph": "2A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 5.EE.Q2(b))", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116825942&loc=SL116722634-122817" }, "r498": { "Name": "Accounting Standards Codification", "Paragraph": "2A", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SAB Topic 5.EE.Q2(f))", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=116825942&loc=SL116722634-122817" }, "r499": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=109238882&loc=d3e39076-109324" }, "r5": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(d)", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760" }, "r50": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312" }, "r500": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324" }, "r501": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(d)", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324" }, "r502": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "05", "SubTopic": "30", "Topic": "740", "URI": "http://asc.fasb.org/extlink&oid=65884525&loc=d3e40913-109327" }, "r503": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "740", "URI": "http://asc.fasb.org/topic&trid=2144680" }, "r504": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463" }, "r505": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=79982066&loc=d3e1486-128463" }, "r506": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=77890550&loc=d3e5227-128473" }, "r507": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Subparagraph": "(c)", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=77890550&loc=d3e5333-128473" }, "r508": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(b)(1)", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479" }, "r509": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(c)(3)", "Topic": "805", "URI": "http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479" }, "r51": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312" }, "r510": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=d3e5283-111683" }, "r511": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4568447-111683" }, "r512": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4568740-111683" }, "r513": { "Name": "Accounting Standards Codification", "Paragraph": "19", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683" }, "r514": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569643-111683" }, "r515": { "Name": "Accounting Standards Codification", "Paragraph": "21", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4613674-111683" }, "r516": { "Name": "Accounting Standards Codification", "Paragraph": "23", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569655-111683" }, "r517": { "Name": "Accounting Standards Codification", "Paragraph": "24", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4616395-111683" }, "r518": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=d3e5614-111684" }, "r519": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684" }, "r52": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=51824906&loc=SL20225877-175312" }, "r520": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684" }, "r521": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684" }, "r522": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(3)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684" }, "r523": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c),(3)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684" }, "r524": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=118582676&loc=d3e5710-111685" }, "r525": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "a", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685" }, "r526": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "b", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685" }, "r527": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=118582676&loc=d3e5747-111685" }, "r528": { "Name": "Accounting Standards Codification", "Paragraph": "4I", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4590271-111686" }, "r529": { "Name": "Accounting Standards Codification", "Paragraph": "4J", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4591551-111686" }, "r53": { "Name": "Accounting Standards Codification", "Paragraph": "16", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=99393222&loc=SL20226024-175313" }, "r530": { "Name": "Accounting Standards Codification", "Paragraph": "4K", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4591552-111686" }, "r531": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.3A-02)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=116822174&loc=d3e355033-122828" }, "r532": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.3A-03)", "Topic": "810", "URI": "http://asc.fasb.org/extlink&oid=116822174&loc=d3e355100-122828" }, "r533": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "810", "URI": "http://asc.fasb.org/topic&trid=2197479" }, "r534": { "Name": "Accounting Standards Codification", "Paragraph": "83", "Publisher": "FASB", "Section": "15", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=117415099&loc=d3e34841-113949" }, "r535": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5579240-113959" }, "r536": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959" }, "r537": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959" }, "r538": { "Name": "Accounting Standards Codification", "Paragraph": "1B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959" }, "r539": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)(i)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41620-113959" }, "r54": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r540": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)(ii)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41620-113959" }, "r541": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41620-113959" }, "r542": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41620-113959" }, "r543": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41638-113959" }, "r544": { "Name": "Accounting Standards Codification", "Paragraph": "4A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959" }, "r545": { "Name": "Accounting Standards Codification", "Paragraph": "4A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959" }, "r546": { "Name": "Accounting Standards Codification", "Paragraph": "4A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)(2)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959" }, "r547": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959" }, "r548": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959" }, "r549": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959" }, "r55": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a),(b),(c)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r550": { "Name": "Accounting Standards Codification", "Paragraph": "4C", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959" }, "r551": { "Name": "Accounting Standards Codification", "Paragraph": "4C", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959" }, "r552": { "Name": "Accounting Standards Codification", "Paragraph": "4C", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959" }, "r553": { "Name": "Accounting Standards Codification", "Paragraph": "4C", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959" }, "r554": { "Name": "Accounting Standards Codification", "Paragraph": "4CC", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL109998890-113959" }, "r555": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(1)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r556": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(2)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r557": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(3)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r558": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(5)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r559": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(6)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r56": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r560": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624177-113959" }, "r561": { "Name": "Accounting Standards Codification", "Paragraph": "4E", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624181-113959" }, "r562": { "Name": "Accounting Standards Codification", "Paragraph": "4EE", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959" }, "r563": { "Name": "Accounting Standards Codification", "Paragraph": "4EE", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959" }, "r564": { "Name": "Accounting Standards Codification", "Paragraph": "4EE", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959" }, "r565": { "Name": "Accounting Standards Codification", "Paragraph": "4H", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959" }, "r566": { "Name": "Accounting Standards Codification", "Paragraph": "4H", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959" }, "r567": { "Name": "Accounting Standards Codification", "Paragraph": "4H", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959" }, "r568": { "Name": "Accounting Standards Codification", "Paragraph": "4J", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708773-113959" }, "r569": { "Name": "Accounting Standards Codification", "Paragraph": "4K", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959" }, "r57": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(e)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r570": { "Name": "Accounting Standards Codification", "Paragraph": "4K", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)(4)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959" }, "r571": { "Name": "Accounting Standards Codification", "Paragraph": "4K", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)(1)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959" }, "r572": { "Name": "Accounting Standards Codification", "Paragraph": "4K", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959" }, "r573": { "Name": "Accounting Standards Codification", "Paragraph": "4L", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5708777-113959" }, "r574": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=d3e41675-113959" }, "r575": { "Name": "Accounting Standards Codification", "Paragraph": "182", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=116861445&loc=SL5629052-113961" }, "r576": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109974929&loc=SL110061172-113977" }, "r577": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109974929&loc=SL110061190-113977" }, "r578": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "25", "Subparagraph": "(a)(1)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986" }, "r579": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "25", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986" }, "r58": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r580": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=109978405&loc=d3e80720-113993" }, "r581": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(c)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994" }, "r582": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(d)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994" }, "r583": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(e)", "Topic": "815", "URI": "http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994" }, "r584": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "Topic": "815", "URI": "http://asc.fasb.org/topic&trid=2229140" }, "r585": { "Name": "Accounting Standards Codification", "Paragraph": "54B", "Publisher": "FASB", "Section": "35", "SubTopic": "10", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117332851&loc=SL7495116-110257" }, "r586": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r587": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r588": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(bb)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r589": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(bbb)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r59": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r590": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(bbb)(1)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r591": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(bbb)(2)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r592": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r593": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r594": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(1a)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r595": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(2)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r596": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)(3)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r597": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258" }, "r598": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258" }, "r599": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258" }, "r6": { "Name": "Accounting Standards Codification", "Paragraph": "5C", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)(2)", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222650&loc=SL51721675-107760" }, "r60": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(h)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r600": { "Name": "Accounting Standards Codification", "Paragraph": "6A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258" }, "r601": { "Name": "Accounting Standards Codification", "Paragraph": "6A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258" }, "r602": { "Name": "Accounting Standards Codification", "Paragraph": "6A", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "820", "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258" }, "r603": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740" }, "r604": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=116690757&loc=d3e13220-108610" }, "r605": { "Name": "Accounting Standards Codification", "Paragraph": "10", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611" }, "r606": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=118260190&loc=d3e13467-108611" }, "r607": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=118260190&loc=d3e13476-108611" }, "r608": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612" }, "r609": { "Name": "Accounting Standards Codification", "Paragraph": "28", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612" }, "r61": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(i)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r610": { "Name": "Accounting Standards Codification", "Paragraph": "30", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612" }, "r611": { "Name": "Accounting Standards Codification", "Paragraph": "30", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612" }, "r612": { "Name": "Accounting Standards Codification", "Paragraph": "31", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14210-108612" }, "r613": { "Name": "Accounting Standards Codification", "Paragraph": "32", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=75031198&loc=d3e14217-108612" }, "r614": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Topic": "825", "URI": "http://asc.fasb.org/extlink&oid=117336053&loc=SL75039408-165497" }, "r615": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "830", "URI": "http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895" }, "r616": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "230", "Topic": "830", "URI": "http://asc.fasb.org/extlink&oid=98513438&loc=d3e33268-110906" }, "r617": { "Name": "Accounting Standards Codification", "Paragraph": "20", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Subparagraph": "(b,c)", "Topic": "830", "URI": "http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900" }, "r618": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "830", "URI": "http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901" }, "r619": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "835", "URI": "http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391" }, "r62": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(i),(j),(k)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r620": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "835", "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399" }, "r621": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "835", "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399" }, "r622": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "835", "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399" }, "r623": { "Name": "Accounting Standards Codification", "Paragraph": "8", "Publisher": "FASB", "Section": "55", "SubTopic": "30", "Topic": "835", "URI": "http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400" }, "r624": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "840", "URI": "http://asc.fasb.org/extlink&oid=77902758&loc=d3e41499-112717" }, "r625": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "840", "URI": "http://asc.fasb.org/extlink&oid=84164758&loc=d3e45031-112735" }, "r626": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "840", "URI": "http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737" }, "r627": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "840", "URI": "http://asc.fasb.org/extlink&oid=84165051&loc=d3e45377-112738" }, "r628": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Subparagraph": "(f)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984" }, "r629": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Subparagraph": "(g)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984" }, "r63": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(i-k)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r630": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Subparagraph": "(j)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984" }, "r631": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984" }, "r632": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977" }, "r633": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977" }, "r634": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918631-209977" }, "r635": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918638-209977" }, "r636": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918643-209977" }, "r637": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(c)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918643-209977" }, "r638": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(a)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r639": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(b)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r64": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(j)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r640": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(e)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r641": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(g)(1)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r642": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(g)(3)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r643": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(g)(4)", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r644": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980" }, "r645": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980" }, "r646": { "Name": "Accounting Standards Codification", "Paragraph": "53", "Publisher": "FASB", "Section": "55", "SubTopic": "20", "Topic": "842", "URI": "http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971" }, "r647": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "850", "URI": "http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864" }, "r648": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "850", "URI": "http://asc.fasb.org/extlink&oid=6457730&loc=d3e39599-107864" }, "r649": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "850", "URI": "http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864" }, "r65": { "Name": "Accounting Standards Codification", "Paragraph": "10A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580" }, "r650": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(bb)", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719" }, "r651": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(bb)(1)", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719" }, "r652": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(bb)(2)", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719" }, "r653": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Subparagraph": "(bb)(3)", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719" }, "r654": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "30", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728" }, "r655": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "50", "Topic": "860", "URI": "http://asc.fasb.org/extlink&oid=116651436&loc=d3e122625-111746" }, "r656": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "340", "Topic": "928", "URI": "http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004" }, "r657": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(10))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r658": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(11))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r659": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(13))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r66": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580" }, "r660": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(15)(1))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r661": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(15)(2))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r662": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(15))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r663": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(16))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r664": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(22))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r665": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(23))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r666": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(6)(a)(1))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r667": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(6))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r668": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03(7)(d))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r669": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03.12)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r67": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580" }, "r670": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03.15(5))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r671": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03.15)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r672": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.9-03.7(a)(7))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878" }, "r673": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04(13)(c))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r674": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04(13)(f))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r675": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04(22))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r676": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04(23))", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r677": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04.11)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r678": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04.2)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r679": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.9-04.9)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260" }, "r68": { "Name": "Accounting Standards Codification", "Paragraph": "14", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e681-108580" }, "r680": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "230", "Subparagraph": "(b)", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6477933&loc=d3e60009-112784" }, "r681": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "320", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=75019621&loc=d3e62586-112803" }, "r682": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "405", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817" }, "r683": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "470", "Topic": "942", "URI": "http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823" }, "r684": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "20", "Subparagraph": "(d)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6480726&loc=d3e6691-158385" }, "r685": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99397103&loc=d3e6811-158387" }, "r686": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99397103&loc=d3e6816-158387" }, "r687": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99397103&loc=d3e6824-158387" }, "r688": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "20", "Subparagraph": "(SAB Topic 5.N.Q1)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=27015749&loc=d3e569934-122904" }, "r689": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(10))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r69": { "Name": "Accounting Standards Codification", "Paragraph": "14A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580" }, "r690": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(13)(a))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r691": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(15)(b)(2))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r692": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(16))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r693": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(1)(b))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r694": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(10))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r695": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(11))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r696": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(12))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r697": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(13)(a)(1))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r698": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(13))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r699": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(14)(b)(2))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r7": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "50", "SubTopic": "20", "Topic": "205", "URI": "http://asc.fasb.org/extlink&oid=109222650&loc=SL51721683-107760" }, "r70": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580" }, "r700": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(14))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r701": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(15)(a))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r702": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(15))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r703": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(16)(a)(1))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r704": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(16))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r705": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(18))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r706": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(23)(a)(4))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r707": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(23)(c))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r708": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(24))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r709": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(25))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r71": { "Name": "Accounting Standards Codification", "Paragraph": "17A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL34724391-108580" }, "r710": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(4))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r711": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(7))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r712": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03(a)(8))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r713": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(c))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r714": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(d))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r715": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(e))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r716": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(f))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r717": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(f,g))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r718": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.1(h))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r719": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.13(c))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r72": { "Name": "Accounting Standards Codification", "Paragraph": "17B", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL34724394-108580" }, "r720": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.14(b)(1))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r721": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.14)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r722": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.15(a))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r723": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.23(c))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r724": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.3)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r725": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "210", "Subparagraph": "(SX 210.7-03.5)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910" }, "r726": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(1))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r727": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(10))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r728": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(12))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r729": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(18))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r73": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580" }, "r730": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(19))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r731": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(2))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r732": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(6))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r733": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04(7)(a))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r734": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04.2)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r735": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04.3(a))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r736": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04.5)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r737": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "220", "Subparagraph": "(SX 210.7-04.5,6,7)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263" }, "r738": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-16(Column J))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915" }, "r739": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-16)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915" }, "r74": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580" }, "r740": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17(Column B))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r741": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17(Column C))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r742": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17(Column D))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r743": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17(Column E))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r744": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17(Column F))", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r745": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Subparagraph": "(SX 210.12-17)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r746": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "235", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915" }, "r747": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(c)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=35755530&loc=d3e11264-158415" }, "r748": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=35755530&loc=d3e11264-158415" }, "r749": { "Name": "Accounting Standards Codification", "Paragraph": "2B", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117419109&loc=SL117422543-158416" }, "r75": { "Name": "Accounting Standards Codification", "Paragraph": "1A", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580" }, "r750": { "Name": "Accounting Standards Codification", "Paragraph": "2B", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117419109&loc=SL117422543-158416" }, "r751": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "30", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117418961&loc=d3e11407-158417" }, "r752": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "55", "SubTopic": "30", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117418976&loc=d3e11522-158419" }, "r753": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "45", "SubTopic": "310", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99404803&loc=d3e21412-158489" }, "r754": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437" }, "r755": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437" }, "r756": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(c)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437" }, "r757": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(cc)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437" }, "r758": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437" }, "r759": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438" }, "r76": { "Name": "Accounting Standards Codification", "Paragraph": "1B", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580" }, "r760": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438" }, "r761": { "Name": "Accounting Standards Codification", "Paragraph": "4B", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438" }, "r762": { "Name": "Accounting Standards Codification", "Paragraph": "4C", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671315-158438" }, "r763": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671317-158438" }, "r764": { "Name": "Accounting Standards Codification", "Paragraph": "4D", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671317-158438" }, "r765": { "Name": "Accounting Standards Codification", "Paragraph": "4E", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671321-158438" }, "r766": { "Name": "Accounting Standards Codification", "Paragraph": "4G", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671329-158438" }, "r767": { "Name": "Accounting Standards Codification", "Paragraph": "4H", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671331-158438" }, "r768": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r769": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r77": { "Name": "Accounting Standards Codification", "Paragraph": "1B", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580" }, "r770": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(c)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r771": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(d)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r772": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Subparagraph": "(e)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r773": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "50", "SubTopic": "40", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=d3e14881-158438" }, "r774": { "Name": "Accounting Standards Codification", "Paragraph": "13H", "Publisher": "FASB", "Section": "55", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117419784&loc=SL117783719-158441" }, "r775": { "Name": "Accounting Standards Codification", "Paragraph": "13H", "Publisher": "FASB", "Section": "55", "SubTopic": "40", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117419784&loc=SL117783719-158441" }, "r776": { "Name": "Accounting Standards Codification", "Paragraph": "9C", "Publisher": "FASB", "Section": "55", "SubTopic": "40", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=116884803&loc=SL65671395-207642" }, "r777": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "65", "SubTopic": "40", "Subparagraph": "(g)(1)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117419843&loc=SL117420844-207641" }, "r778": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "50", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6483535&loc=d3e16392-158451" }, "r779": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "50", "Subparagraph": "(c)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6483535&loc=d3e16392-158451" }, "r78": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e557-108580" }, "r780": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "505", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529" }, "r781": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "505", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529" }, "r782": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "505", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486098&loc=d3e24746-158529" }, "r783": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "505", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486098&loc=d3e24746-158529" }, "r784": { "Name": "Accounting Standards Codification", "Paragraph": "6", "Publisher": "FASB", "Section": "50", "SubTopic": "505", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486098&loc=d3e24790-158529" }, "r785": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "55", "SubTopic": "505", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=82848697&loc=d3e24938-158530" }, "r786": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "55", "SubTopic": "505", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=82848697&loc=d3e24959-158530" }, "r787": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "60", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117422154&loc=SL117422156-227712" }, "r788": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "605", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=84167274&loc=d3e27175-158546" }, "r789": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(a)(2)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r79": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116657188&loc=SL116659661-227067" }, "r790": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(b)(1)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r791": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(b)(2)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r792": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(b)(3)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r793": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(c)(1)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r794": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(c)(2)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r795": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "605", "Subparagraph": "(c)(3)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547" }, "r796": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "55", "SubTopic": "605", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99379264&loc=d3e27758-158548" }, "r797": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "55", "SubTopic": "605", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=99379264&loc=d3e27830-158548" }, "r798": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "45", "SubTopic": "80", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=6484091&loc=d3e19268-158472" }, "r799": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "80", "Subparagraph": "(e)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420044&loc=d3e19393-158473" }, "r8": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765" }, "r80": { "Name": "Accounting Standards Codification", "Paragraph": "15", "Publisher": "FASB", "Section": "55", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=118951672&loc=d3e1436-108581" }, "r800": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "80", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420044&loc=SL117422267-158473" }, "r801": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "80", "Subparagraph": "(c)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420044&loc=SL117422267-158473" }, "r802": { "Name": "Accounting Standards Codification", "Paragraph": "17", "Publisher": "FASB", "Section": "55", "SubTopic": "80", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=118959010&loc=SL117422397-158474" }, "r803": { "Name": "Accounting Standards Codification", "Paragraph": "18", "Publisher": "FASB", "Section": "55", "SubTopic": "80", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=118959010&loc=SL117422401-158474" }, "r804": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30785-158569" }, "r805": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(a)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r806": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r807": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(1)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r808": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(10)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r809": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(2)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r81": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "65", "SubTopic": "10", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116657190&loc=SL116659633-172590" }, "r810": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(3)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r811": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(4)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r812": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(5)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r813": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(6)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r814": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(8)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r815": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Subparagraph": "(b)(9)", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r816": { "Name": "Accounting Standards Codification", "Paragraph": "3", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30806-158569" }, "r817": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "50", "SubTopic": "805", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420430&loc=d3e30862-158569" }, "r818": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "55", "SubTopic": "805", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420656&loc=d3e31071-158570" }, "r819": { "Name": "Accounting Standards Codification", "Publisher": "FASB", "SubTopic": "805", "Topic": "944", "URI": "http://asc.fasb.org/subtopic&trid=2560393" }, "r82": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(210.5-03(11))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r820": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "45", "SubTopic": "825", "Topic": "944", "URI": "http://asc.fasb.org/extlink&oid=117420823&loc=d3e32546-158582" }, "r821": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12(2)(i))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611133-123010" }, "r822": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12.2(ii))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611133-123010" }, "r823": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12C(1)(a))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010" }, "r824": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12C(1)(b))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010" }, "r825": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12C(2))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010" }, "r826": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-12C.1(b),2)", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010" }, "r827": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12C(2))-", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010" }, "r828": { "Name": "Accounting Standards Codification", "Paragraph": "5", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-13(1))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611282-123010" }, "r829": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-15(Column A))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010" }, "r83": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03(1))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r830": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-15(Column B))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010" }, "r831": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-15(Column C))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010" }, "r832": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-15(Column D))", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010" }, "r833": { "Name": "Accounting Standards Codification", "Paragraph": "7", "Publisher": "FASB", "Section": "S99", "SubTopic": "320", "Subparagraph": "(SX 210.12-15)", "Topic": "946", "URI": "http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010" }, "r834": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "310", "Subparagraph": "(SX 210.12-29(Footnote 3))", "Topic": "948", "URI": "http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014" }, "r835": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "310", "Subparagraph": "(SX 210.12-29(Footnote 4))", "Topic": "948", "URI": "http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014" }, "r836": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "50", "SubTopic": "740", "Topic": "954", "URI": "http://asc.fasb.org/extlink&oid=6491622&loc=d3e9504-115650" }, "r837": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "360", "Subparagraph": "(SX 210.12-28(Footnote 2))", "Topic": "970", "URI": "http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024" }, "r838": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "S99", "SubTopic": "360", "Subparagraph": "(SX 210.12-28(Footnote 4))", "Topic": "970", "URI": "http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024" }, "r839": { "Name": "Accounting Standards Codification", "Paragraph": "1", "Publisher": "FASB", "Section": "55", "SubTopic": "840", "Topic": "980", "URI": "http://asc.fasb.org/extlink&oid=84167768&loc=d3e56872-110439" }, "r84": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03(12))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r840": { "Name": "Exchange Act", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "b" }, "r841": { "Name": "Exchange Act", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "d1-1" }, "r842": { "Name": "Forms 10-K, 10-Q, 20-F", "Number": "240", "Publisher": "SEC", "Section": "13", "Subsection": "a-1-" }, "r843": { "Name": "Forms 10-K, 20-F, 40-F", "Number": "240", "Publisher": "SEC", "Section": "15", "Subsection": "d-1" }, "r844": { "Name": "Regulation 12B", "Number": "240", "Publisher": "SEC", "Section": "12", "Subsection": "b-2" }, "r845": { "Name": "Regulation S-T", "Number": "232", "Publisher": "SEC", "Section": "405" }, "r846": { "Footnote": "2", "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "28" }, "r847": { "Footnote": "3", "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "29" }, "r848": { "Footnote": "4", "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "28" }, "r849": { "Footnote": "4", "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "29" }, "r85": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03(20))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r850": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "Column B", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r851": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "Column C", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r852": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "Column D", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r853": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "Column E", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r854": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "Column F", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r855": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "a", "Publisher": "SEC", "Section": "12", "Subsection": "04" }, "r856": { "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "15" }, "r857": { "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "16" }, "r858": { "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "12", "Subsection": "17" }, "r859": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "c", "Publisher": "SEC", "Section": "3", "Subparagraph": "4", "Subsection": "10" }, "r86": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03(21))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r860": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "d", "Publisher": "SEC", "Section": "3", "Subparagraph": "4", "Subsection": "10" }, "r861": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "e", "Publisher": "SEC", "Section": "3", "Subparagraph": "4", "Subsection": "10" }, "r862": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "f", "Publisher": "SEC", "Section": "3", "Subparagraph": "4", "Subsection": "10" }, "r863": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "(m)", "Publisher": "SEC", "Section": "4", "Subparagraph": "(1)(iii)", "Subsection": "08" }, "r864": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "c", "Publisher": "SEC", "Section": "5", "Subparagraph": "Schedule I", "Subsection": "04" }, "r865": { "Name": "Regulation S-X (SX)", "Number": "210", "Paragraph": "c", "Publisher": "SEC", "Section": "7", "Subparagraph": "Schedule II", "Subsection": "05" }, "r866": { "Name": "Regulation S-X (SX)", "Number": "210", "Publisher": "SEC", "Section": "9", "Subsection": "06" }, "r87": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03(7)(c))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r88": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.1(e))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r89": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.19)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r9": { "Name": "Accounting Standards Codification", "Paragraph": "4", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(d)", "Topic": "210", "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6812-107765" }, "r90": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.7(a),(b))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r91": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.7(c),9(a))", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r92": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.8)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r93": { "Name": "Accounting Standards Codification", "Paragraph": "2", "Publisher": "FASB", "Section": "S99", "SubTopic": "10", "Subparagraph": "(SX 210.5-03.9)", "Topic": "220", "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227" }, "r94": { "Name": "Accounting Standards Codification", "Paragraph": "11", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3151-108585" }, "r95": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585" }, "r96": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(c)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585" }, "r97": { "Name": "Accounting Standards Codification", "Paragraph": "12", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585" }, "r98": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(a)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585" }, "r99": { "Name": "Accounting Standards Codification", "Paragraph": "13", "Publisher": "FASB", "Section": "45", "SubTopic": "10", "Subparagraph": "(b)", "Topic": "230", "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585" } }, "version": "2.1" }