2.4.1.9 Html 796 553 1 false 176 0 false 5 false false R1.htm 00090 - Document - Document and Entity Information Sheet http://principal.com/role/DocumentDocumentAndEntityInformation Document and Entity Information true false R2.htm 00100 - Statement - Consolidated Statements of Financial Position Sheet http://principal.com/role/StatementConsolidatedStatementsOfFinancialPosition Consolidated Statements of Financial Position false false R3.htm 00105 - Statement - Consolidated Statements of Financial Position (Parenthetical) Sheet http://principal.com/role/StatementConsolidatedStatementsOfFinancialPositionParenthetical Consolidated Statements of Financial Position (Parenthetical) false false R4.htm 00200 - Statement - Consolidated Statements of Operations Sheet http://principal.com/role/StatementConsolidatedStatementsOfOperations Consolidated Statements of Operations false false R5.htm 00300 - Statement - Consolidated Statements of Comprehensive Income Sheet http://principal.com/role/StatementConsolidatedStatementsOfComprehensiveIncome Consolidated Statements of Comprehensive Income false false R6.htm 00400 - Statement - Consolidated Statements of Stockholders' Equity Sheet http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquity Consolidated Statements of Stockholders' Equity false false R7.htm 00405 - Statement - Consolidated Statements of Stockholders' Equity (Parenthetical) Sheet http://principal.com/role/StatementConsolidatedStatementsOfStockholdersEquityParenthetical Consolidated Statements of Stockholders' Equity (Parenthetical) false false R8.htm 00500 - Statement - Consolidated Statements of Cash Flows Sheet http://principal.com/role/StatementConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows false false R9.htm 10101 - Disclosure - Nature of Operations and Significant Accounting Policies Sheet http://principal.com/role/DisclosureNatureOfOperationsAndSignificantAccountingPolicies Nature of Operations and Significant Accounting Policies false false R10.htm 10201 - Disclosure - Variable Interest Entities Sheet http://principal.com/role/DisclosureVariableInterestEntities Variable Interest Entities false false R11.htm 10301 - Disclosure - Investments Sheet http://principal.com/role/DisclosureInvestments Investments false false R12.htm 10401 - Disclosure - Derivative Financial Instruments Sheet http://principal.com/role/DisclosureDerivativeFinancialInstruments Derivative Financial Instruments false false R13.htm 10501 - Disclosure - Income Taxes Sheet http://principal.com/role/DisclosureIncomeTaxes Income Taxes false false R14.htm 10601 - Disclosure - Employee and Agent Benefits Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefits Employee and Agent Benefits false false R15.htm 10701 - Disclosure - Contingencies, Guarantees and Indemnifications Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnifications Contingencies, Guarantees and Indemnifications false false R16.htm 10801 - Disclosure - Stockholders' Equity Sheet http://principal.com/role/DisclosureStockholdersEquity Stockholders' Equity false false R17.htm 10901 - Disclosure - Fair Value Measurements Sheet http://principal.com/role/DisclosureFairValueMeasurements Fair Value Measurements false false R18.htm 11001 - Disclosure - Segment Information Sheet http://principal.com/role/DisclosureSegmentInformation Segment Information false false R19.htm 11101 - Disclosure - Stock-Based Compensation Plans Sheet http://principal.com/role/DisclosureStockBasedCompensationPlans Stock-Based Compensation Plans false false R20.htm 11201 - Disclosure - Earnings Per Common Share Sheet http://principal.com/role/DisclosureEarningsPerCommonShare Earnings Per Common Share false false R21.htm 11301 - Disclosure - Condensed Consolidating Financial Information Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformation Condensed Consolidating Financial Information false false R22.htm 20102 - 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 R23.htm 30203 - Disclosure - Variable Interest Entities (Tables) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesTables Variable Interest Entities (Tables) false false R24.htm 30303 - Disclosure - Investments (Tables) Sheet http://principal.com/role/DisclosureInvestmentsTables Investments (Tables) false false R25.htm 30403 - Disclosure - Derivative Financial Instruments (Tables) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsTables Derivative Financial Instruments (Tables) false false R26.htm 30503 - Disclosure - Income Taxes (Tables) Sheet http://principal.com/role/DisclosureIncomeTaxesTables Income Taxes (Tables) false false R27.htm 30603 - Disclosure - Employee and Agent Benefits (Tables) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsTables Employee and Agent Benefits (Tables) false false R28.htm 30803 - Disclosure - Stockholders' Equity (Tables) Sheet http://principal.com/role/DisclosureStockholdersEquityTables Stockholders' Equity (Tables) false false R29.htm 30903 - Disclosure - Fair Value Measurements (Tables) Sheet http://principal.com/role/DisclosureFairValueMeasurementsTables Fair Value Measurements (Tables) false false R30.htm 31003 - Disclosure - Segment Information (Tables) Sheet http://principal.com/role/DisclosureSegmentInformationTables Segment Information (Tables) false false R31.htm 31103 - Disclosure - Stock-Based Compensation Plans (Tables) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansTables Stock-Based Compensation Plans (Tables) false false R32.htm 31203 - Disclosure - Earnings Per Common Share (Tables) Sheet http://principal.com/role/DisclosureEarningsPerCommonShareTables Earnings Per Common Share (Tables) false false R33.htm 31303 - Disclosure - Condensed Consolidating Financial Information (Tables) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationTables Condensed Consolidating Financial Information (Tables) false false R34.htm 40101 - 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 R35.htm 40201 - Disclosure - Variable Interest Entities (Details) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesDetails Variable Interest Entities (Details) false false R36.htm 40202 - Disclosure - Variable Interest Entities (Details 2) Sheet http://principal.com/role/DisclosureVariableInterestEntitiesDetails2 Variable Interest Entities (Details 2) false false R37.htm 40301 - Disclosure - Investments (Details) Sheet http://principal.com/role/DisclosureInvestmentsDetails Investments (Details) false false R38.htm 40302 - Disclosure - Investments (Details 2) Sheet http://principal.com/role/DisclosureInvestmentsDetails2 Investments (Details 2) false false R39.htm 40303 - Disclosure - Investments (Details 3) Sheet http://principal.com/role/DisclosureInvestmentsDetails3 Investments (Details 3) false false R40.htm 40304 - Disclosure - Investments (Details 4) Sheet http://principal.com/role/DisclosureInvestmentsDetails4 Investments (Details 4) false false R41.htm 40305 - Disclosure - Investments (Details 5) Sheet http://principal.com/role/DisclosureInvestmentsDetails5 Investments (Details 5) false false R42.htm 40306 - Disclosure - Investments (Details 6) Sheet http://principal.com/role/DisclosureInvestmentsDetails6 Investments (Details 6) false false R43.htm 40307 - Disclosure - Investments (Details 7) Sheet http://principal.com/role/DisclosureInvestmentsDetails7 Investments (Details 7) false false R44.htm 40308 - Disclosure - Investments (Details 8) Sheet http://principal.com/role/DisclosureInvestmentsDetails8 Investments (Details 8) false false R45.htm 40309 - Disclosure - Investments (Details 9) Sheet http://principal.com/role/DisclosureInvestmentsDetails9 Investments (Details 9) false false R46.htm 40310 - Disclosure - Investments (Details 10) Sheet http://principal.com/role/DisclosureInvestmentsDetails10 Investments (Details 10) false false R47.htm 40311 - Disclosure - Investments (Details 11) Sheet http://principal.com/role/DisclosureInvestmentsDetails11 Investments (Details 11) false false R48.htm 40312 - Disclosure - Investments (Details 12) Sheet http://principal.com/role/DisclosureInvestmentsDetails12 Investments (Details 12) false false R49.htm 40313 - Disclosure - Investments (Details 13) Sheet http://principal.com/role/DisclosureInvestmentsDetails13 Investments (Details 13) false false R50.htm 40314 - Disclosure - Investments (Details 14) Sheet http://principal.com/role/DisclosureInvestmentsDetails14 Investments (Details 14) false false R51.htm 40315 - Disclosure - Investments (Details 15) Sheet http://principal.com/role/DisclosureInvestmentsDetails15 Investments (Details 15) false false R52.htm 40316 - Disclosure - Investments (Details 16) Sheet http://principal.com/role/DisclosureInvestmentsDetails16 Investments (Details 16) false false R53.htm 40401 - Disclosure - Derivative Financial Instruments (Details) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails Derivative Financial Instruments (Details) false false R54.htm 40402 - Disclosure - Derivative Financial Instruments (Details 2) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails2 Derivative Financial Instruments (Details 2) false false R55.htm 40403 - Disclosure - Derivative Financial Instruments (Details 3) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails3 Derivative Financial Instruments (Details 3) false false R56.htm 40404 - Disclosure - Derivative Financial Instruments (Details 4) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails4 Derivative Financial Instruments (Details 4) false false R57.htm 40405 - Disclosure - Derivative Financial Instruments (Details 5) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails5 Derivative Financial Instruments (Details 5) false false R58.htm 40406 - Disclosure - Derivative Financial Instruments (Details 6) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails6 Derivative Financial Instruments (Details 6) false false R59.htm 40407 - Disclosure - Derivative Financial Instruments (Details 7) Sheet http://principal.com/role/DisclosureDerivativeFinancialInstrumentsDetails7 Derivative Financial Instruments (Details 7) false false R60.htm 40501 - Disclosure - Income Taxes (Details) Sheet http://principal.com/role/DisclosureIncomeTaxesDetails Income Taxes (Details) false false R61.htm 40601 - Disclosure - Employee and Agent Benefits (Details) Sheet http://principal.com/role/DisclosureEmployeeAndAgentBenefitsDetails Employee and Agent Benefits (Details) false false R62.htm 40701 - Disclosure - Contingencies, Guarantees and Indemnifications (Details) Sheet http://principal.com/role/DisclosureContingenciesGuaranteesAndIndemnificationsDetails Contingencies, Guarantees and Indemnifications (Details) false false R63.htm 40801 - Disclosure - Stockholders' Equity (Details) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails Stockholders' Equity (Details) false false R64.htm 40802 - Disclosure - Stockholders' Equity (Details 2) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails2 Stockholders' Equity (Details 2) false false R65.htm 40803 - Disclosure - Stockholders' Equity (Details 3) Sheet http://principal.com/role/DisclosureStockholdersEquityDetails3 Stockholders' Equity (Details 3) false false R66.htm 40901 - Disclosure - Fair Value Measurements (Details) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails Fair Value Measurements (Details) false false R67.htm 40902 - Disclosure - Fair Value Measurements (Details 2) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails2 Fair Value Measurements (Details 2) false false R68.htm 40903 - Disclosure - Fair Value Measurements (Details 3) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails3 Fair Value Measurements (Details 3) false false R69.htm 40904 - Disclosure - Fair Value Measurements (Details 4) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails4 Fair Value Measurements (Details 4) false false R70.htm 40905 - Disclosure - Fair Value Measurements (Details 5) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails5 Fair Value Measurements (Details 5) false false R71.htm 40906 - Disclosure - Fair Value Measurements (Details 6) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails6 Fair Value Measurements (Details 6) false false R72.htm 40907 - Disclosure - Fair Value Measurements (Details 7) Sheet http://principal.com/role/DisclosureFairValueMeasurementsDetails7 Fair Value Measurements (Details 7) false false R73.htm 41001 - Disclosure - Segment Information (Details) Sheet http://principal.com/role/DisclosureSegmentInformationDetails Segment Information (Details) false false R74.htm 41002 - Disclosure - Segment Information (Details 2) Sheet http://principal.com/role/DisclosureSegmentInformationDetails2 Segment Information (Details 2) false false R75.htm 41003 - Disclosure - Segment Information (Details 3) Sheet http://principal.com/role/DisclosureSegmentInformationDetails3 Segment Information (Details 3) false false R76.htm 41004 - Disclosure - Segment Information (Details 4) Sheet http://principal.com/role/DisclosureSegmentInformationDetails4 Segment Information (Details 4) false false R77.htm 41101 - Disclosure - Stock-Based Compensation Plans (Details) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails Stock-Based Compensation Plans (Details) false false R78.htm 41102 - Disclosure - Stock-Based Compensation Plans (Details 2) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails2 Stock-Based Compensation Plans (Details 2) false false R79.htm 41103 - Disclosure - Stock-Based Compensation Plans (Details 3) Sheet http://principal.com/role/DisclosureStockBasedCompensationPlansDetails3 Stock-Based Compensation Plans (Details 3) false false R80.htm 41201 - Disclosure - Earnings Per Common Share (Details) Sheet http://principal.com/role/DisclosureEarningsPerCommonShareDetails Earnings Per Common Share (Details) false false R81.htm 41301 - Disclosure - Condensed Consolidating Financial Information (Details) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails Condensed Consolidating Financial Information (Details) false false R82.htm 41302 - Disclosure - Condensed Consolidating Financial Information (Details 2) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails2 Condensed Consolidating Financial Information (Details 2) false false R83.htm 41303 - Disclosure - Condensed Consolidating Financial Information (Details 3) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails3 Condensed Consolidating Financial Information (Details 3) false false R84.htm 41304 - Disclosure - Condensed Consolidating Financial Information (Details 4) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails4 Condensed Consolidating Financial Information (Details 4) false false R85.htm 41305 - Disclosure - Condensed Consolidating Financial Information (Details 5) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails5 Condensed Consolidating Financial Information (Details 5) false false R86.htm 41306 - Disclosure - Condensed Consolidating Financial Information (Details 6) Sheet http://principal.com/role/DisclosureCondensedConsolidatingFinancialInformationDetails6 Condensed Consolidating Financial Information (Details 6) false false All Reports Book All Reports Element pfg_FairValueInputsCreditSpreadRate had a mix of decimals attribute values: 3 4. 'Monetary' elements on report '40202 - Disclosure - Variable Interest Entities (Details 2)' had a mix of different decimal attribute values. 'Shares' elements on report '41101 - Disclosure - Stock-Based Compensation Plans (Details)' had a mix of different decimal attribute values. Process Flow-Through: 00100 - Statement - Consolidated Statements of Financial Position Process Flow-Through: Removing column 'Mar. 31, 2014' Process Flow-Through: Removing column 'Dec. 31, 2013' Process Flow-Through: 00105 - Statement - Consolidated Statements of Financial Position (Parenthetical) Process Flow-Through: 00200 - Statement - Consolidated Statements of Operations Process Flow-Through: 00300 - Statement - Consolidated Statements of Comprehensive Income Process Flow-Through: 00405 - Statement - Consolidated Statements of Stockholders' Equity (Parenthetical) Process Flow-Through: 00500 - Statement - Consolidated Statements of Cash Flows pfg-20150331.xml pfg-20150331.xsd pfg-20150331_cal.xml pfg-20150331_def.xml pfg-20150331_lab.xml pfg-20150331_pre.xml true true