1.0.0.3 false Consolidated Statements of Operations (USD $) In Millions, except Per Share data false 1 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 3 Revenues 1 us-gaap_RevenuesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false No definition available. false 4 Premiums and other considerations 2 us-gaap_PremiumsEarnedNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 3750600000 3750.6 false false 2 true true 4209200000 4209.2 false false 3 true true 4634100000 4634.1 false false No definition available. No authoritative reference available. false 5 Fees and other revenues 2 us-gaap_FeesAndCommissions us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2096000000 2096.0 false false 2 false true 2426500000 2426.5 false false 3 false true 2634700000 2634.7 false false No definition available. No authoritative reference available. false 6 Net investment income 2 us-gaap_NetInvestmentIncome us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3400800000 3400.8 false false 2 false true 3994300000 3994.3 false false 3 false true 3966500000 3966.5 false false No definition available. No authoritative reference available. false 7 Net realized capital gains (losses), excluding impairment losses on available-for-sale securities 2 pfg_NetGainLossExcludingAvailableForSaleImpairments pfg false credit duration monetary This item represents the net realized and unrealized gains (losses), excluding impairment losses on available-for-sale... false false false false false false false false false 1 false true 54900000 54.9 false false 2 false true -214800000 -214.8 false false 3 false true -14700000 -14.7 false false 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. No authoritative reference available. false 8 Total other-than-temporary impairment losses on available-for-sale securities 2 pfg_OtherThanTemporaryImpairmentLossesInvestmentsAvailableForSaleSecurities pfg false debit duration monetary The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less... false false false false false false false false false 1 false true -714100000 -714.1 false false 2 false true -479300000 -479.3 false false 3 false true -314100000 -314.1 false false The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less 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. No authoritative reference available. false 9 Portion of impairment losses on fixed maturities, available-for-sale recognized in other comprehensive income 2 pfg_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterest pfg false debit duration monetary The amount of other than temporary impairment loss on a debt security, categorized as either Available-for-sale or... false false false false false false false false false 1 false true 260900000 260.9 false false 2 false false 0 0 false false 3 false false 0 0 false false The amount of other than temporary impairment loss on a debt security, categorized as either Available-for-sale or Held-to-maturity, 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 deducted 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. No authoritative reference available. false 10 Net impairment losses on available-for-sale securities 2 pfg_NetImpairmentLossesOnAvailableForSaleSecurities pfg false debit duration monetary This item represents the amount of loss recognized for other than temporary impairments of investments in debt and equity... false false false false false false false false false 1 false true -453200000 -453.2 false false 2 false true -479300000 -479.3 false false 3 false true -314100000 -314.1 false false This item represents the amount of loss recognized for other than temporary impairments of investments in debt and equity securities, net of noncredit impairment losses on certain debt securities that are recognized in other comprehensive income. No authoritative reference available. true 11 Net realized capital losses 2 us-gaap_GainLossOnInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -398300000 -398.3 false false 2 false true -694100000 -694.1 false false 3 false true -328800000 -328.8 false false No definition available. No authoritative reference available. true 12 Total revenues 2 us-gaap_Revenues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 8849100000 8849.1 false false 2 false true 9935900000 9935.9 false false 3 false true 10906500000 10906.5 false false No definition available. No authoritative reference available. true 13 Expenses 1 us-gaap_BenefitsLossesAndExpensesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false No definition available. false 14 Benefits, claims and settlement expenses 2 us-gaap_PolicyholderBenefitsAndClaimsIncurredNet us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 5334500000 5334.5 false false 2 false true 6219900000 6219.9 false false 3 false true 6435300000 6435.3 false false No definition available. No authoritative reference available. false 15 Dividends to policyholders 2 us-gaap_PolicyholderDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 242200000 242.2 false false 2 false true 267300000 267.3 false false 3 false true 293800000 293.8 false false No definition available. No authoritative reference available. false 16 Operating expenses 2 pfg_OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization pfg false debit duration monetary Expenses other than those for payments of benefits, claims and policyholder dividends that are incurred related to the... false false false false false false false false false 1 false true 2526600000 2526.6 false false 2 false true 2987400000 2987.4 false false 3 false true 3105000000 3105.0 false false 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 policy acquisitions costs ("DPAC"), amortization of DPAC, depreciation and amortization expense, interest expense on corporate debt, compensation costs and other general and administrative expenses. No authoritative reference available. false 17 Total expenses 2 us-gaap_BenefitsLossesAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 8103300000 8103.3 false false 2 false true 9474600000 9474.6 false false 3 false true 9834100000 9834.1 false false No definition available. No authoritative reference available. true 18 Income from continuing operations before income taxes 1 pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes pfg false credit duration monetary The sum of income (expense), including income (expense) attributable to the noncontrolling interest, before income taxes for... false false false false false false false false false 1 false true 745800000 745.8 false false 2 false true 461300000 461.3 false false 3 false true 1072400000 1072.4 false false The sum of income (expense), including income (expense) attributable to the noncontrolling interest, before income taxes for continuing operations. No authoritative reference available. true 19 Income taxes (benefits) 1 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 100100000 100.1 false false 2 false true -4500000 -4.5 false false 3 false true 208100000 208.1 false false No definition available. No authoritative reference available. false 20 Income from continuing operations, net of related income taxes 1 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 645700000 645.7 false false 2 false true 465800000 465.8 false false 3 false true 864300000 864.3 false false No definition available. No authoritative reference available. true 21 Income from discontinued operations, net of related income taxes 1 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false true 20200000 20.2 false false No definition available. No authoritative reference available. false 22 Net income 1 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 645700000 645.7 false false 2 false true 465800000 465.8 false false 3 false true 884500000 884.5 false false No definition available. No authoritative reference available. true 23 Net income attributable to noncontrolling interest 1 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 23000000 23.0 false false 2 false true 7700000 7.7 false false 3 false true 24200000 24.2 false false No definition available. No authoritative reference available. false 24 Net income attributable to Principal Financial Group, Inc. 1 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 622700000 622.7 false false 2 false true 458100000 458.1 false false 3 false true 860300000 860.3 false false No definition available. No authoritative reference available. true 25 Preferred stock dividends 1 us-gaap_PreferredStockDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 33000000 33.0 false false 2 false true 33000000 33.0 false false 3 false true 33000000 33.0 false false No definition available. No authoritative reference available. false 26 Net income available to common stockholders 1 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 589700000 589.7 false false 2 true true 425100000 425.1 false false 3 true true 827300000 827.3 false false No definition available. No authoritative reference available. true 28 Basic earnings per common share: 2 us-gaap_EarningsPerShareBasicAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false No definition available. false 29 Income from continuing operations, net of related income taxes (in dollars per share) 3 us-gaap_IncomeLossFromContinuingOperationsPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 1.98 1.98 false false 2 true true 1.64 1.64 false false 3 true true 3.04 3.04 false false No definition available. No authoritative reference available. false 30 Income from discontinued operations, net of related income taxes (in dollars per share) 3 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 false false 0 0 false false 2 false false 0 0 false false 3 true true 0.08 0.08 false false No definition available. No authoritative reference available. false 31 Net income (in dollars per share) 3 us-gaap_EarningsPerShareBasic us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 1.98 1.98 false false 2 true true 1.64 1.64 false false 3 true true 3.12 3.12 false false No definition available. No authoritative reference available. true 32 Diluted earnings per common share: 2 us-gaap_EarningsPerShareDilutedAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false No definition available. false 33 Income from continuing operations, net of related income taxes (in dollars per share) 3 us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 1.97 1.97 false false 2 true true 1.63 1.63 false false 3 true true 3.01 3.01 false false No definition available. No authoritative reference available. false 34 Income from discontinued operations, net of related income taxes (in dollars per share) 3 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 false false 0 0 false false 2 false false 0 0 false false 3 true true 0.08 0.08 false false No definition available. No authoritative reference available. false 35 Net income (in dollars per share) 3 us-gaap_EarningsPerShareDiluted us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 1.97 1.97 false false 2 true true 1.63 1.63 false false 3 true true 3.09 3.09 false false No definition available. No authoritative reference available. true false 3 32 false HundredThousands UnKnown Hundreds false true