2.4.0.84111 - Disclosure - Segment Information (Details 2)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$1true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information2false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse23117000002311.7USD$falsetruefalse2truefalsefalse21363000002136.3USD$falsetruefalse3truefalsefalse45500000004550.0USD$falsetruefalse4truefalsefalse42437000004243.7USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues3false 4pfg_SegmentReportingInformationNetRealizedCapitalGainsLossespfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-101500000-101.5USD$falsefalsefalse2truefalsefalse-21700000-21.7USD$falsefalsefalse3truefalsefalse-176700000-176.7USD$falsefalsefalse4truefalsefalse-52100000-52.1USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNet realized capital gains (losses) net of recognition of deferred front-end fee revenues for sales charges on retirement products and services and certain market value adjustments to fee revenues. It excludes periodic settlements and accruals on derivatives not designated as hedging instruments.No definition available.false2Net realized capital gains (losses), net of related revenue adjustments4false 4pfg_ExitedGroupMedicalInsuranceBusinessRevenuespfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse4000000.4USD$falsefalsefalse2truefalsefalse40000004.0USD$falsefalsefalse3truefalsefalse40000004.0USD$falsefalsefalse4truefalsefalse2290000022.9USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAggregate revenue recognized during the period for an exited group medical insurance business that does not qualify for discontinued accounting treatment.No definition available.false2Exited group medical insurance business5false 4us-gaap_Revenuesus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse22106000002210.6USD$falsefalsefalse2truefalsefalse21186000002118.6USD$falsefalsefalse3truefalsefalse43773000004377.3USD$falsefalsefalse4truefalsefalse42145000004214.5USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 true2Total revenues6false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse271400000271.4USD$falsefalsefalse2truefalsefalse210900000210.9USD$falsefalsefalse3truefalsefalse504700000504.7USD$falsefalsefalse4truefalsefalse426200000426.2USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)7false 4pfg_SegmentReportingInformationNetRealizedCapitalGainsLossesNetOfTaxAndAdjustmentspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-47600000-47.6USD$falsefalsefalse2truefalsefalse-39300000-39.3USD$falsefalsefalse3truefalsefalse-104000000-104.0USD$falsefalsefalse4truefalsefalse-49200000-49.2USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNet realized capital gains (losses) net of income taxes, related changes in the amortization pattern of deferred acquisition costs and sales inducements, recognition of deferred front-end fee revenues for sales charges on retirement products and services, net realized capital gains and losses distributed, noncontrolling interest capital gains and losses and certain market value adjustments to fee revenues. Net realized capital gains (losses), as adjusted, exclude periodic settlements and accruals on derivative instruments not designated as hedging instruments and exclude certain market value adjustments of embedded derivatives.No definition available.false2Net realized capital gains (losses), as adjusted8false 4pfg_SegmentReportingInformationOtherAdjustmentsAfterTaxpfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-1500000-1.5USD$falsefalsefalse2truefalsefalse-4000000-4.0USD$falsefalsefalse3truefalsefalse-100000-0.1USD$falsefalsefalse4truefalsefalse-5500000-5.5USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe after-tax impact of specific transactions that are not recurring in nature and that management does not believe are indicative of overall operating trends.No definition available.false2Other after-tax adjustments9false 4us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse222300000222.3USD$falsefalsefalse2truefalsefalse167600000167.6USD$falsefalsefalse3truefalsefalse400600000400.6USD$falsefalsefalse4truefalsefalse371500000371.5USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNet income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 9 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. true2Net income (loss) available to common stockholders10false 4pfg_GroupMedicalInsuranceBusinessNotDiscontinuedOperationpfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-1500000-1.5USD$falsefalsefalse2truefalsefalse-4000000-4.0USD$falsefalsefalse3truefalsefalse-100000-0.1USD$falsefalsefalse4truefalsefalse-5500000-5.5USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe after-tax gain (loss) resulting from an exited group medical insurance business that is not a discontinued operation. It is included in income from continuing operations in the income statement.No definition available.false2After-tax gains (losses) associated with exited group medical insurance business that does not qualify for discontinued operations11false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5false USDtruefalse$D2013Q2_AggregateSegmentMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseAggregate Segmentsus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_AggregateSegmentMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Aggregate Segments12true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information13false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse23117000002311.7USD$falsefalsefalse2truefalsefalse21363000002136.3USD$falsefalsefalse3truefalsefalse45500000004550.0USD$falsefalsefalse4truefalsefalse42437000004243.7USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues14false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse271400000271.4USD$falsefalsefalse2truefalsefalse210900000210.9USD$falsefalsefalse3truefalsefalse504700000504.7USD$falsefalsefalse4truefalsefalse426200000426.2USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)15false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse9false USDtruefalse$D2013Q2_SegmentRetirementAndInvestorServicesMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseRetirement and Investor Servicesus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_SegmentRetirementAndInvestorServicesMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Retirement and Investor Services16true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information17false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse11488000001148.8USD$falsefalsefalse2truefalsefalse10812000001081.2USD$falsefalsefalse3truefalsefalse22511000002251.1USD$falsefalsefalse4truefalsefalse21363000002136.3USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues18false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse172300000172.3USD$falsefalsefalse2truefalsefalse141700000141.7USD$falsefalsefalse3truefalsefalse342300000342.3USD$falsefalsefalse4truefalsefalse285300000285.3USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)19false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse13false USDtruefalse$D2013Q2_SegmentPrincipalGlobalInvestorsMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalsePrincipal Global Investorsus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_SegmentPrincipalGlobalInvestorsMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Principal Global Investors20true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information21false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse168200000168.2USD$falsefalsefalse2truefalsefalse141100000141.1USD$falsefalsefalse3truefalsefalse321900000321.9USD$falsefalsefalse4truefalsefalse279200000279.2USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues22false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse2900000029.0USD$falsefalsefalse2truefalsefalse1820000018.2USD$falsefalsefalse3truefalsefalse4930000049.3USD$falsefalsefalse4truefalsefalse3440000034.4USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)23false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse17false USDtruefalse$D2013Q2_SegmentPrincipalInternationalMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalsePrincipal Internationalus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_SegmentPrincipalInternationalMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Principal International24true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information25false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse275100000275.1USD$falsefalsefalse2truefalsefalse210600000210.6USD$falsefalsefalse3truefalsefalse522600000522.6USD$falsefalsefalse4truefalsefalse473100000473.1USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues26false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse5830000058.3USD$falsefalsefalse2truefalsefalse3150000031.5USD$falsefalsefalse3truefalsefalse102900000102.9USD$falsefalsefalse4truefalsefalse7560000075.6USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)27false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse21false USDtruefalse$D2013Q2_SegmentUSInsuranceSolutionsMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseU.S. Insurance Solutionsus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_SegmentUSInsuranceSolutionsMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0U.S. Insurance Solutions28true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information29false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse773000000773.0USD$falsefalsefalse2truefalsefalse751500000751.5USD$falsefalsefalse3truefalsefalse15510000001551.0USD$falsefalsefalse4truefalsefalse14485000001448.5USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues30false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse4720000047.2USD$falsefalsefalse2truefalsefalse5020000050.2USD$falsefalsefalse3truefalsefalse8290000082.9USD$falsefalsefalse4truefalsefalse100400000100.4USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOperating earnings is a measure of profit or loss for the operating segments that is used to evaluate performance on a basis comparable to that used by securities analysts. It is derived by adjusting net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)31false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse25false USDtruefalse$D2013Q2_SegmentCorporateMemberhttp://www.sec.gov/CIK0001126328duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseCorporateus-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldipfg_SegmentCorporateMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Corporate32true 3us-gaap_SegmentReportingInformationLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information33false 4us-gaap_SegmentReportingInformationRevenueus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-53400000-53.4USD$falsefalsefalse2truefalsefalse-48100000-48.1USD$falsefalsefalse3truefalsefalse-96600000-96.6USD$falsefalsefalse4truefalsefalse-93400000-93.4USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 27 -Subparagraph a, b, c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Operating revenues34false 4pfg_OperatingEarningspfg_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-35400000-35.4USD$falsetruefalse2truefalsefalse-30700000-30.7USD$falsetruefalse3truefalsefalse-72700000-72.7USD$falsetruefalse4truefalsefalse-69500000-69.5USD$falsetruefalsexbrli:monetaryItemTypemonetaryOperating 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 net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments management believes are not indicative of overall operating trends.No definition available.false2Operating earnings (loss)falseSegment Information (Details 2) (USD $)HundredThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://principal.com/role/DisclosureSegmentInformationDetails2434