2.4.0.6 Html 1125 899 1 false 258 0 false 14 false false R1.htm 0000 - Document - Document and Entity Information Sheet http://principal.com/role/DocumentAndEntityInformation Document and Entity Information true false R2.htm 0010 - Statement - Consolidated Statements of Financial Position Sheet http://principal.com/role/BalanceSheet Consolidated Statements of Financial Position false false R3.htm 0015 - Statement - Consolidated Statements of Financial Position (Parenthetical) Sheet http://principal.com/role/BalanceSheetParenthetical Consolidated Statements of Financial Position (Parenthetical) false false R4.htm 0020 - Statement - Consolidated Statements of Operations Sheet http://principal.com/role/StatementOfIncome Consolidated Statements of Operations false false R5.htm 0030 - Statement - Consolidated Statements of Stockholders' Equity Sheet http://principal.com/role/StatementOfStockholdersEquity Consolidated Statements of Stockholders' Equity false false R6.htm 0040 - Statement - Consolidated Statements of Cash Flows Sheet http://principal.com/role/CashFlows Consolidated Statements of Cash Flows false false R7.htm 1010 - Disclosure - Nature of Operations and Significant Accounting Policies Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPolicies Nature of Operations and Significant Accounting Policies false false R8.htm 1020 - Disclosure - Goodwill and Other Intangible Assets Sheet http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssets Goodwill and Other Intangible Assets false false R9.htm 1030 - Disclosure - Variable Interest Entities Sheet http://principal.com/role/DisclosureVariableInterestEntities Variable Interest Entities false false R10.htm 1040 - Disclosure - Investments Sheet http://principal.com/role/DisclosureInvestments Investments false false R11.htm 1050 - Disclosure - Derivative Financial Instruments Sheet http://principal.com/role/DisclosureDerivativeFinancialInstruments Derivative Financial Instruments false false R12.htm 1060 - Disclosure - Closed Block Sheet http://principal.com/role/DisclosureClosedBlock Closed Block false false R13.htm 1070 - Disclosure - Deferred Policy Acquisition Costs Sheet http://principal.com/role/DisclosureDeferredPolicyAcquisitionCosts Deferred Policy Acquisition Costs false false R14.htm 1080 - Disclosure - Insurance Liabilities Sheet http://principal.com/role/DisclosureInsuranceLiabilities Insurance Liabilities false false R15.htm 1090 - Disclosure - Debt Sheet http://principal.com/role/DisclosureDebt Debt false false R16.htm 1100 - Disclosure - Income Taxes Sheet http://principal.com/role/DisclosureIncomeTaxes Income Taxes false false R17.htm 1110 - Disclosure - Employee and Agent Benefits Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefits Employee and Agent Benefits false false R18.htm 1120 - Disclosure - Contingencies, Guarantees and Indemnifications Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnifications Contingencies, Guarantees and Indemnifications false false R19.htm 1130 - Disclosure - Stockholders' Equity Sheet http://principal.com/role/DisclosureStockholdersEquity Stockholders' Equity false false R20.htm 1140 - Disclosure - Fair Value Measurements Sheet http://principal.com/role/DisclosureFairValueMeasurements Fair Value Measurements false false R21.htm 1150 - Disclosure - Statutory Insurance Financial Information Sheet http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformation Statutory Insurance Financial Information false false R22.htm 1160 - Disclosure - Segment Information Sheet http://principal.com/role/DisclosureSegmentInformation Segment Information false false R23.htm 1170 - Disclosure - Stock-Based Compensation Plans Sheet http://principal.com/role/DisclosureStockBasedCompensationPlans Stock-Based Compensation Plans false false R24.htm 1180 - Disclosure - Earnings Per Common Share Sheet http://principal.com/role/DisclosureEarningsPerCommonShare Earnings Per Common Share false false R25.htm 1190 - Disclosure - Quarterly Results of Operations (Unaudited) Sheet http://principal.com/role/DisclosureQuarterlyResultsOfOperations Quarterly Results of Operations (Unaudited) false false R26.htm 1200 - Disclosure - Condensed Consolidating Financial Information Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformation Condensed Consolidating Financial Information false false R27.htm 1210 - Disclosure - Schedule I - Summary of Investments - Other Than Investments in Related Parties Sheet http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedParties Schedule I - Summary of Investments - Other Than Investments in Related Parties false false R28.htm 1220 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) Sheet http://principal.com/role/DisclosureScheduleIICondensedFinancialInformationOfRegistrantParentOnly Schedule II - Condensed Financial Information of Registrant (Parent Only) false false R29.htm 1230 - Disclosure - Schedule III - Supplementary Insurance Information Sheet http://principal.com/role/DisclosureScheduleIIISupplementaryInsuranceInformation Schedule III - Supplementary Insurance Information false false R30.htm 1240 - Disclosure - Schedule IV - Reinsurance Sheet http://principal.com/role/DisclosureScheduleIVReinsurance Schedule IV - Reinsurance false false R31.htm 2010 - Disclosure - Nature of Operations and Significant Accounting Policies (Policies) Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesPolicies Nature of Operations and Significant Accounting Policies (Policies) false false R32.htm 3010 - Disclosure - Nature of Operations and Significant Accounting Policies (Tables) Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesTables Nature of Operations and Significant Accounting Policies (Tables) false false R33.htm 3020 - Disclosure - Goodwill and Other Intangible Assets (Tables) Sheet http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables Goodwill and Other Intangible Assets (Tables) false false R34.htm 3030 - Disclosure - Variable Interest Entities (Tables) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesTables Variable Interest Entities (Tables) false false R35.htm 3040 - Disclosure - Investments (Tables) Sheet http://principal.com/role/DisclosureInvestmentsTables Investments (Tables) false false R36.htm 3050 - Disclosure - Derivative Financial Instruments (Tables) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables Derivative Financial Instruments (Tables) false false R37.htm 3060 - Disclosure - Closed Block (Tables) Sheet http://principal.com/role/DisclosureClosedBlockTables Closed Block (Tables) false false R38.htm 3070 - Disclosure - Deferred Policy Acquisition Costs (Tables) Sheet http://principal.com/role/DisclosureDeferredPolicyAcquisitionCostsTables Deferred Policy Acquisition Costs (Tables) false false R39.htm 3080 - Disclosure - Insurance Liabilities (Tables) Sheet http://principal.com/role/DisclosureInsuranceLiabilitiesTables Insurance Liabilities (Tables) false false R40.htm 3090 - Disclosure - Debt (Tables) Sheet http://principal.com/role/DisclosureDebtTables Debt (Tables) false false R41.htm 3100 - Disclosure - Income Tax (Tables) Sheet http://principal.com/role/DisclosureIncomeTaxTables Income Tax (Tables) false false R42.htm 3110 - Disclosure - Employee and Agent Benefits (Tables) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables Employee and Agent Benefits (Tables) false false R43.htm 3120 - Disclosure - Contingencies, Guarantees and Indemnifications (Tables) Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnificationsTables Contingencies, Guarantees and Indemnifications (Tables) false false R44.htm 3130 - Disclosure - Stockholders' Equity (Tables) Sheet http://principal.com/role/DisclosureStockholdersEquityTables Stockholders' Equity (Tables) false false R45.htm 3140 - Disclosure - Fair Value Measurements (Tables) Sheet http://principal.com/role/DisclosureFairValueOfMeasurementsTables Fair Value Measurements (Tables) false false R46.htm 3150 - Disclosure - Statutory Insurance Financial Information (Tables) Sheet http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationTables Statutory Insurance Financial Information (Tables) false false R47.htm 3160 - Disclosure - Segment Information (Tables) Sheet http://principal.com/role/DisclosureSegmentInformationTables Segment Information (Tables) false false R48.htm 3170 - Disclosure - Stock-Based Compensation Plans (Tables) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansTables Stock-Based Compensation Plans (Tables) false false R49.htm 3180 - Disclosure - Earnings Per Common Share (Tables) Sheet http://principal.com/role/DisclosureEarningsPerCommonShareTables Earnings Per Common Share (Tables) false false R50.htm 3190 - Disclosure - Quarterly Results of Operations (Unaudited) (Tables) Sheet http://principal.com/role/DisclosureQuarterlyResultsOfOperationsTables Quarterly Results of Operations (Unaudited) (Tables) false false R51.htm 3200 - Disclosure - Condensed Consolidating Financial Information (Tables) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationTables Condensed Consolidating Financial Information (Tables) false false R52.htm 4010 - Disclosure - Nature of Operations and Significant Accounting Policies (Details) Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesDetails Nature of Operations and Significant Accounting Policies (Details) false false R53.htm 4011 - Disclosure - Nature of Operations and Significant Accounting Policies (Details 2) Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPoliciesDetails2 Nature of Operations and Significant Accounting Policies (Details 2) false false R54.htm 4020 - Disclosure - Goodwill and Other Intangible Assets (Details) Sheet http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails Goodwill and Other Intangible Assets (Details) false false R55.htm 4021 - Disclosure - Goodwill and Other Intangible Assets (Details 2) Sheet http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails2 Goodwill and Other Intangible Assets (Details 2) false false R56.htm 4022 - Disclosure - Goodwill and Other Intangible Assets (Details 3) Sheet http://principal.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails3 Goodwill and Other Intangible Assets (Details 3) false false R57.htm 4030 - Disclosure - Variable Interest Entities (Details) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesDetails Variable Interest Entities (Details) false false R58.htm 4031 - Disclosure - Variable Interest Entities (Details 2) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesDetails2 Variable Interest Entities (Details 2) false false R59.htm 4040 - Disclosure - Investments (Details) Sheet http://principal.com/role/DisclosureInvestmentsDetails Investments (Details) false false R60.htm 4041 - Disclosure - Investments (Details 2) Sheet http://principal.com/role/DisclosureInvestmentsDetails2 Investments (Details 2) false false R61.htm 4042 - Disclosure - Investments (Details 3) Sheet http://principal.com/role/DisclosureInvestmentsDetails3 Investments (Details 3) false false R62.htm 4043 - Disclosure - Investments (Details 4) Sheet http://principal.com/role/DisclosureInvestmentsDetails4 Investments (Details 4) false false R63.htm 4044 - Disclosure - Investments (Details 5) Sheet http://principal.com/role/DisclosureInvestmentsDetails5 Investments (Details 5) false false R64.htm 4045 - Disclosure - Investments (Details 6) Sheet http://principal.com/role/DisclosureInvestmentsDetails6 Investments (Details 6) false false R65.htm 4046 - Disclosure - Investments (Details 7) Sheet http://principal.com/role/DisclosureInvestmentsDetails7 Investments (Details 7) false false R66.htm 4047 - Disclosure - Investments (Details 8) Sheet http://principal.com/role/DisclosureInvestmentsDetails8 Investments (Details 8) false false R67.htm 4048 - Disclosure - Investments (Details 9) Sheet http://principal.com/role/DisclosureInvestmentsDetails9 Investments (Details 9) false false R68.htm 4049 - Disclosure - Investments (Details 10) Sheet http://principal.com/role/DisclosureInvestmentsDetails10 Investments (Details 10) false false R69.htm 4050 - Disclosure - Investments (Details 11) Sheet http://principal.com/role/DisclosureInvestmentsDetails11 Investments (Details 11) false false R70.htm 4051 - Disclosure - Investments (Details 12) Sheet http://principal.com/role/DisclosureInvestmentsDetails12 Investments (Details 12) false false R71.htm 4052 - Disclosure - Investments (Details 13) Sheet http://principal.com/role/DisclosureInvestmentsDetails13 Investments (Details 13) false false R72.htm 4053 - Disclosure - Investments (Details 14) Sheet http://principal.com/role/DisclosureInvestmentsDetails14 Investments (Details 14) false false R73.htm 4054 - Disclosure - Investments (Details 15) Sheet http://principal.com/role/DisclosureInvestmentsDetails15 Investments (Details 15) false false R74.htm 4055 - Disclosure - Derivative Financial Instruments (Details 1) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails1 Derivative Financial Instruments (Details 1) false false R75.htm 4056 - Disclosure - Derivative Financial Instruments (Details 2) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails2 Derivative Financial Instruments (Details 2) false false R76.htm 4057 - Disclosure - Derivative Financial Instruments (Details 3) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails3 Derivative Financial Instruments (Details 3) false false R77.htm 4058 - Disclosure - Derviative Financial Instruments (Details 4) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails4 Derviative Financial Instruments (Details 4) false false R78.htm 4059 - Disclosure - Derivative Financial Instruments (Details 5) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails5 Derivative Financial Instruments (Details 5) false false R79.htm 4060 - Disclosure - Derivative Financial Instruments (Details 6) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails6 Derivative Financial Instruments (Details 6) false false R80.htm 4061 - Disclosure - Derivative Financial Instruments (Details 7) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails7 Derivative Financial Instruments (Details 7) false false R81.htm 4062 - Disclosure - Closed Block (Details) Sheet http://principal.com/role/DisclosureClosedBlockDetails Closed Block (Details) false false R82.htm 4063 - Disclosure - Closed Block (Details 2) Sheet http://principal.com/role/DisclosureClosedBlockDetails2 Closed Block (Details 2) false false R83.htm 4064 - Disclosure - Closed Block (Details 3) Sheet http://principal.com/role/DisclosureClosedBlockDetails3 Closed Block (Details 3) false false R84.htm 4070 - Disclosure - Deferred Policy Acquisition Costs (Details) Sheet http://principal.com/role/DisclosureDeferredPolicyAcquisitionCostsDetails Deferred Policy Acquisition Costs (Details) false false R85.htm 4080 - Disclosure - Insurance Liabilities (Details) Sheet http://principal.com/role/DisclosureInsuranceLiabilitiesDetails Insurance Liabilities (Details) false false R86.htm 4081 - Disclosure - Insurance Liabilities (Details 2) Sheet http://principal.com/role/DisclosureInsuranceLiabilitiesDetails2 Insurance Liabilities (Details 2) false false R87.htm 4082 - Disclosure - Insurance Liabilities (Details 3) Sheet http://principal.com/role/DisclosureInsuranceLiabilitiesDetails3 Insurance Liabilities (Details 3) false false R88.htm 4090 - Disclosure - Debt (Details) Sheet http://principal.com/role/DisclosureDebtDetails Debt (Details) false false R89.htm 4091 - Disclosure - Debt (Details 2) Sheet http://principal.com/role/DisclosureDebtDetails2 Debt (Details 2) false false R90.htm 4092 - Disclosure - Debt (Details 3) Sheet http://principal.com/role/DisclosureDebtDetails3 Debt (Details 3) false false R91.htm 4093 - Disclosure - Debt (Details 4) Sheet http://principal.com/role/DisclosureDebtDetails4 Debt (Details 4) false false R92.htm 4094 - Disclosure - Debt (Details 5) Sheet http://principal.com/role/DisclosureDebtDetails5 Debt (Details 5) false false R93.htm 4095 - Disclosure - Debt (Details 6) Sheet http://principal.com/role/DisclosureDebtDetails6 Debt (Details 6) false false R94.htm 4100 - Disclosure - Income Taxes (Details) Sheet http://principal.com/role/DisclosureIncomeTaxesDetails Income Taxes (Details) false false R95.htm 4110 - Disclosure - Employee and Agent Benefits (Details) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails Employee and Agent Benefits (Details) false false R96.htm 4111 - Disclosure - Employee and Agent Benefits (Details 2) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails2 Employee and Agent Benefits (Details 2) false false R97.htm 4112 - Disclosure - Employee and Agent Benefits (Details 3) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails3 Employee and Agent Benefits (Details 3) false false R98.htm 4113 - Disclosure - Employee and Agent Benefits (Details 4) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails4 Employee and Agent Benefits (Details 4) false false R99.htm 4114 - Disclosure - Employee and Agent Benefits (Details 5) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails5 Employee and Agent Benefits (Details 5) false false R100.htm 4115 - Disclosure - Employee and Agent Benefits (Details 6) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails6 Employee and Agent Benefits (Details 6) false false R101.htm 4116 - Disclosure - Employee and Agent Benefits (Details 7) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails7 Employee and Agent Benefits (Details 7) false false R102.htm 4117 - Disclosure - Employee and Agent Benefits (Details 8) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails8 Employee and Agent Benefits (Details 8) false false R103.htm 4120 - Disclosure - Contingencies, Guarantees and Indemnifications (Details) Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnificationsDetails Contingencies, Guarantees and Indemnifications (Details) false false R104.htm 4121 - Disclosure - Contingencies, Guarantees and Indemnifications (Details 2) Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnificationsDetails2 Contingencies, Guarantees and Indemnifications (Details 2) false false R105.htm 4130 - Disclosure - Stockholders' Equity (Details) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails Stockholders' Equity (Details) false false R106.htm 4131 - Disclosure - Stockholders' Equity (Details 2) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails2 Stockholders' Equity (Details 2) false false R107.htm 4132 - Disclosure - Stockholders' Equity (Details 3) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails3 Stockholders' Equity (Details 3) false false R108.htm 4141 - Disclosure - Fair Value Measurements (Details) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails Fair Value Measurements (Details) false false R109.htm 4142 - Disclosure - Fair Value Measurements (Details 2) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails2 Fair Value Measurements (Details 2) false false R110.htm 4143 - Disclosure - Fair Value Measurements (Details 3) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails3 Fair Value Measurements (Details 3) false false R111.htm 4144 - Disclosure - Fair Value Measurements (Details 4) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails4 Fair Value Measurements (Details 4) false false R112.htm 4145 - Disclosure - Fair Value Measurements (Details 5) Sheet http://principal.com/role/DisclosureFairValueOfMeasurementsDetails5 Fair Value Measurements (Details 5) false false R113.htm 4146 - Disclosure - Fair Value Measurements (Details 6) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails6 Fair Value Measurements (Details 6) false false R114.htm 4150 - Disclosure - Statutory Insurance Financial Information (Details) Sheet http://principal.com/role/DisclosureStatutoryInsuranceFinancialInformationDetails Statutory Insurance Financial Information (Details) false false R115.htm 4161 - Disclosure - Segment Information (Details) Sheet http://principal.com/role/DisclosureSegmentInformationDetails Segment Information (Details) false false R116.htm 4162 - Disclosure - Segment Information (Details 2) Sheet http://principal.com/role/DisclosureSegmentInformationDetails2 Segment Information (Details 2) false false R117.htm 4163 - Disclosure - Segment Information (Details 3) Sheet http://principal.com/role/DisclosureSegmentInformationDetails3 Segment Information (Details 3) false false R118.htm 4164 - Disclosure - Segment Information (Details 4) Sheet http://principal.com/role/DisclosureSegmentInformationDetails4 Segment Information (Details 4) false false R119.htm 4165 - Disclosure - Segment Information (Details 5) Sheet http://principal.com/role/DisclosureSegmentInformationDetails5 Segment Information (Details 5) false false R120.htm 4170 - Disclosure - Stock-Based Compensation Plans (Details) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails Stock-Based Compensation Plans (Details) false false R121.htm 4171 - Disclosure - Stock-Based Compensation Plans (Details 2) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails2 Stock-Based Compensation Plans (Details 2) false false R122.htm 4172 - Disclosure - Stock-Based Compensation Plans (Details 3) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails3 Stock-Based Compensation Plans (Details 3) false false R123.htm 4173 - Disclosure - Stock-Based Compensation Plans (Details 4) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails4 Stock-Based Compensation Plans (Details 4) false false R124.htm 4180 - Disclosure - Earnings Per Common Share (Details) Sheet http://principal.com/role/DisclosureEarningsPerCommonShareDetails Earnings Per Common Share (Details) false false R125.htm 4190 - Disclosure - Quarterly Results of Operations (Unaudited) (Details) Sheet http://principal.com/role/DisclosureQuarterlyResultsOfOperationsDetails Quarterly Results of Operations (Unaudited) (Details) false false R126.htm 4191 - Disclosure - Quarterly Results of Operations (Unaudited) (Details 2) Sheet http://principal.com/role/DisclosureQuarterlyResultsOfOperationsDetails2 Quarterly Results of Operations (Unaudited) (Details 2) false false R127.htm 4201 - Disclosure - Condensed Consolidating Financial Information (Details) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails Condensed Consolidating Financial Information (Details) false false R128.htm 4202 - Disclosure - Condensed Consolidating Financial Information (Details 2) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails2 Condensed Consolidating Financial Information (Details 2) false false R129.htm 4203 - Disclosure - Condensed Consolidating Financial Information (Details 3) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails3 Condensed Consolidating Financial Information (Details 3) false false R130.htm 4204 - Disclosure - Condensed Consolidating Financial Information (Details 4) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails4 Condensed Consolidating Financial Information (Details 4) false false R131.htm 4205 - Disclosure - Condensed Consolidating Financial Information (Details 5) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails5 Condensed Consolidating Financial Information (Details 5) false false R132.htm 4206 - Disclosure - Condensed Consolidating Financial Information (Details 6) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails6 Condensed Consolidating Financial Information (Details 6) false false R133.htm 4210 - Disclosure - Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) Sheet http://principal.com/role/DisclosureScheduleISummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesDetails Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) false false R134.htm 4220 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details) Sheet http://principal.com/role/DisclosureScheduleIICondensedFinancialInformationOfRegistrantParentOnlyDetails Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details) false false R135.htm 4221 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 2) Sheet http://principal.com/role/DisclosureScheduleIICondensedFinancialInformationOfRegistrantParentOnlyDetails2 Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 2) false false R136.htm 4222 - Disclosure - Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 3) Sheet http://principal.com/role/DisclosureScheduleIICondensedFinancialInformationOfRegistrantParentOnlyDetails3 Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 3) false false R137.htm 4230 - Disclosure - Schedule III - Supplementary Insurance Information (Details) Sheet http://principal.com/role/DisclosureScheduleIIISupplementaryInsuranceInformationDetails Schedule III - Supplementary Insurance Information (Details) false false R138.htm 4240 - Disclosure - Schedule IV - Reinsurance (Details) Sheet http://principal.com/role/DisclosureScheduleIVReinsuranceDetails Schedule IV - Reinsurance (Details) false false All Reports Book All Reports Element us-gaap_OperatingLossCarryforwards had a mix of decimals attribute values: -6 -5. 'Monetary' elements on report '4011 - Disclosure - Nature of Operations and Significant Accounting Policies (Details 2)' had a mix of different decimal attribute values. 'Monetary' elements on report '4031 - Disclosure - Variable Interest Entities (Details 2)' had a mix of different decimal attribute values. 'Monetary' elements on report '4043 - Disclosure - Investments (Details 4)' had a mix of different decimal attribute values. 'Monetary' elements on report '4081 - Disclosure - Insurance Liabilities (Details 2)' had a mix of different decimal attribute values. Process Flow-Through: 0010 - Statement - Consolidated Statements of Financial Position Process Flow-Through: Removing column 'Dec. 31, 2009' Process Flow-Through: Removing column 'Dec. 31, 2008' Process Flow-Through: 0015 - Statement - Consolidated Statements of Financial Position (Parenthetical) Process Flow-Through: Removing column 'Dec. 31, 2009' Process Flow-Through: Removing column 'Dec. 31, 2008' Process Flow-Through: 0020 - Statement - Consolidated Statements of Operations Process Flow-Through: 0040 - Statement - Consolidated Statements of Cash Flows pfg-20111231.xml pfg-20111231.xsd pfg-20111231_cal.xml pfg-20111231_def.xml pfg-20111231_lab.xml pfg-20111231_pre.xml true true