2.4.0.8010000 - Document - Risk/Return Summary {Unlabeled}falsefalsefalse1false falsefalseD2013Q1Sept20_dei_DocumentInformationDocumentAxis_ck0000898745_PFIProspectusClassABCPMemberhttp://www.sec.gov/CIK0000898745duration2013-09-20T00:00:002013-09-20T00:00:001false 2ck0000898745_SupplementTextBlockck0000898745_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-weight:bold;">Supplement dated September 20, 2013</font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-weight:bold;">to the Classes A, B, C, and P Shares Prospectus</font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-weight:bold;">for Principal Funds, Inc.</font></div><div style="line-height:120%;padding-bottom:4px;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-weight:bold;">dated March 1, 2013</font></div><div style="line-height:120%;padding-bottom:4px;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;">(as supplemented on March 14, 2013, March 28, 2013, April 2, 2013, May 9, 2013, and June 14, 2013)</font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;">This supplement updates information currently in the Prospectus. Retain this supplement with the Prospectus.</font></div><div style="line-height:120%;padding-bottom:4px;text-align:left;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;padding-bottom:16px;text-align:left;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-weight:bold;">FUND SUMMARIES</font></div></div>falsefalsefalseus-types:textBlockItemTypestringSupplement [Text Block]No definition available.false0Supplement [Text Block]2false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00Global Diversified Income Fund [Member]falsefalsefalse2false truefalseD2013Q1Sept20_dei_DocumentInformationDocumentAxis_ck0000898745_PFIProspectusClassABCPMember_dei_LegalEntityAxis_ck0000898745_S000024296Memberhttp://www.sec.gov/CIK0000898745duration2013-09-20T00:00:002013-09-20T00:00:00falsefalsePFI Prospectus - Class A, B, C, Pdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldick0000898745_PFIProspectusClassABCPMemberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseGlobal Diversified Income Fund [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000898745_S000024296Memberdei_LegalEntityAxisexplicitMembernanafalse0Global Diversified Income Fund [Member]3false 2rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Global Diversified Income Fundfalsefalsefalsexbrli:stringItemTypestringRisk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicatedReference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 false0Risk/Return [Heading]4false 2rr_StrategyHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00On or about November 6, 2013, under the Principal Investment Strategies heading, delete the paragraph that begins “A portion of the Fund's assets is invested in publicly-listed infrastructure companies” and substitute:falsefalsefalsexbrli:stringItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a false0Strategy [Heading]5false 2rr_StrategyNarrativeTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;">A portion of the Fund's assets is invested in publicly-listed infrastructure companies (domestic and foreign public utility, energy, and transportation companies). Publicly-listed infrastructure equity securities trade on an exchange and include companies involved to a significant extent in providing products, services or equipment for: transportation (including toll roads, airports, railways, and ports); the generation, transmission or distribution of electricity, gas or water (utilities); or telecommunications activities as well as in companies involved in the discovery, development, production, generation, transmission, refinement, measurement, trading, marketing or distribution of energy.</font></div></div>falsefalsefalseus-types:textBlockItemTypestringPrincipal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Subsection a false0Strategy Narrative [Text Block]falseRisk/Return Summary (PFI Prospectus - Class A, B, C, P)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://xbrl.sec.gov/rr/role/RiskReturn15