2.4.0.84042 - Disclosure - Investments (Details 3)truefalseIn Millions, unless otherwise specifiedfalse1false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2012Q2http://www.sec.gov/CIK0001126328duration2012-04-01T00:00:002012-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0001126328duration2013-01-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$D2012Q2YTDhttp://www.sec.gov/CIK0001126328duration2012-01-01T00:00:002012-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3pfg_AvailableForSaleDebtSecuritiesNetRealizedCapitalGainsAbstractpfg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Fixed maturities, available-for-sale:2false 4pfg_AvailableForSaleDebtSecuritiesGrossRealizedGainpfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse63000006.3USD$falsetruefalse2truefalsefalse44000004.4USD$falsetruefalse3truefalsefalse2180000021.8USD$falsetruefalse4truefalsefalse1970000019.7USD$falsetruefalsexbrli:monetaryItemTypemonetaryThis item represents the gross realized gains realized on the sale of debt securities categorized neither as held-to-maturity nor trading securities.No definition available.false2Gross gains3false 4pfg_AvailableForSaleDebtSecuritiesGrossRealizedLosspfg_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-29700000-29.7falsefalsefalse2truefalsefalse-50800000-50.8falsefalsefalse3truefalsefalse-80400000-80.4falsefalsefalse4truefalsefalse-86900000-86.9falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the gross realized losses realized on the sale of debt securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments of the subject investments in debt securities.No definition available.false2Gross losses4false 4us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableforsaleSecuritiesus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-2100000-2.1falsefalsefalse2truefalsefalse1710000017.1falsefalsefalse3truefalsefalse1810000018.1falsefalsefalse4truefalsefalse2200000022.0falsefalsefalsexbrli:monetaryItemTypemonetaryBefore tax amount of other than temporary impairment (OTTI) on a debt security, categorized as available-for-sale, recognized in other comprehensive income (loss).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 16C -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15D -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income5false 4pfg_AvailableForSaleDebtSecuritiesHedgingNetpfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-60800000-60.8falsefalsefalse2truefalsefalse2340000023.4falsefalsefalse3truefalsefalse-89800000-89.8falsefalsefalse4truefalsefalse67000006.7falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the net gains/losses on available-for-sale debt securities that are the hedged item in a designated fair value hedge.No definition available.false2Hedging, net6false 3pfg_TradingDebtSecuritiesRealizedGainLosspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-6300000-6.3falsefalsefalse2truefalsefalse-2000000-2.0falsefalsefalse3truefalsefalse-6200000-6.2falsefalsefalse4truefalsefalse10000001.0falsefalsefalsexbrli:monetaryItemTypemonetaryTrading securities represent securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time). This item represents the net gains/losses realized from the sale, exchange, redemption or retirement of debt securities held as trading and the unrealized holding gains/losses for these securities.No definition available.false2Fixed maturities, trading7true 3pfg_AvailableForSaleEquitySecuritiesNetRealizedCapitalGainsAbstractpfg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Equity securities, available-for-sale:8false 4pfg_AvailableForSaleEquitySecuritiesGrossRealizedGainpfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1000000.1falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse1000000.1falsefalsefalse4truefalsefalse1000000.1falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the gross realized gains realized on the sale of equity securities categorized neither as held-to-maturity nor trading securities.No definition available.false2Gross gains9false 4pfg_AvailableForSaleEquitySecuritiesGrossRealizedLosspfg_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-100000-0.1falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse-100000-0.1falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the gross realized losses realized on the sale of equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments of the subject investments in equity securities.No definition available.false2Gross losses10false 3pfg_TradingEquitySecuritiesRealizedGainLosspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse52000005.2falsefalsefalse2truefalsefalse-3500000-3.5falsefalsefalse3truefalsefalse1150000011.5falsefalsefalse4truefalsefalse3070000030.7falsefalsefalsexbrli:monetaryItemTypemonetaryTrading securities represent securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time). This item represents the net gains/losses realized from the sale, exchange, redemption or retirement of equity securities held as trading and the unrealized holding gains/losses for these securities.No definition available.false2Equity securities, trading11false 3pfg_MortgageLoanRealizedGainLosspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-10800000-10.8falsefalsefalse2truefalsefalse-10200000-10.2falsefalsefalse3truefalsefalse-17000000-17.0falsefalsefalse4truefalsefalse-21300000-21.3falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the net realized gains/losses on the sale of mortgage loans. Additionally, this item includes gains/losses related to changes in the mortgage loan reserve/valuation allowance to cover probable credit losses on the loan portfolio.No definition available.false2Mortgage loans12false 3us-gaap_GainLossOnDerivativeInstrumentsNetPretaxus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1180000011.8falsefalsefalse2truefalsefalse28000002.8falsefalsefalse3truefalsefalse3000000030.0falsefalsefalse4truefalsefalse3040000030.4falsefalsefalsexbrli:monetaryItemTypemonetaryAggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 false2Derivatives13false 3pfg_OtherRealizedGainLosspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse63000006.3falsefalsefalse2truefalsefalse1900000019.0falsefalsefalse3truefalsefalse-19000000-19.0falsefalsefalse4truefalsefalse-8900000-8.9falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the net gains/losses realized from the sale and unrealized holding gains/losses for invested assets (e.g., real estate, seed money) not classified as fixed maturities, equity securities, mortgage loans or derivatives. Additionally, this item includes foreign currency exchange gains/losses.No definition available.false2Other14false 3us-gaap_GainLossOnInvestmentsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse-80100000-80.1falsefalsefalse2truefalsefalse2000000.2falsefalsefalse3truefalsefalse-131000000-131.0falsefalsefalse4truefalsefalse-6500000-6.5falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. 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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. true2Net realized capital gains (losses)15true 2pfg_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsAbstractpfg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Proceeds from sales of investments16false 3us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse540200000540.2USD$falsetruefalse2truefalsefalse285900000285.9USD$falsetruefalse3truefalsefalse11003000001100.3USD$falsetruefalse4truefalsefalse716100000716.1USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 21 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Proceeds from sales of investments in fixed maturities, available-for-salefalseInvestments (Details 3) (USD $)HundredThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://principal.com/role/DisclosureInvestmentsDetails3416