2.4.0.8010000 - Document - Risk/Return Summary {Unlabeled}falsefalsefalse1false falsefalseD2013Q2June14_dei_DocumentInformationDocumentAxis_ck0000898745_PFIProspectusClassACPMemberhttp://www.sec.gov/CIK0000898745duration2013-06-14T00:00:002013-06-14T00:00:001false 2ck0000898745_SupplementTextBlockck0000898745_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:center;font-size:11pt;"><font style="font-family:Arial;font-size:11pt;font-weight:bold;">Supplement dated June 14, 2013</font></div><div style="line-height:120%;text-align:center;font-size:11pt;"><font style="font-family:Arial;font-size:11pt;font-weight:bold;">to the Classes A, C, and P Shares Prospectus</font></div><div style="line-height:120%;text-align:center;font-size:11pt;"><font style="font-family:Arial;font-size:11pt;font-weight:bold;">for Principal Funds, Inc.</font></div><div style="line-height:120%;padding-bottom:16px;text-align:center;font-size:11pt;"><font style="font-family:Arial;font-size:11pt;font-weight:bold;">dated December 28, 2012</font></div><div style="line-height:120%;padding-bottom:16px;text-align:center;font-size:11pt;"><font style="font-family:Arial;font-size:11pt;">(as supplemented on February 8, 2013, March 15, 2013 and April 29, 2013)</font></div><div style="line-height:120%;text-align:left;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%;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 style="line-height:120%;font-size:10pt;"><hr></hr><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalseus-types:textBlockItemTypestringSupplement [Text Block]No definition available.false0Supplement [Text Block]2false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00Global Multi-Strategy Fund [Member]falsefalsefalse2false truefalseD2013Q2June14_dei_DocumentInformationDocumentAxis_ck0000898745_PFIProspectusClassACPMember_dei_LegalEntityAxis_ck0000898745_S000033960Memberhttp://www.sec.gov/CIK0000898745duration2013-06-14T00:00:002013-06-14T00:00:00falsefalsePFI Prospectus Class ACPdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldick0000898745_PFIProspectusClassACPMemberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseGlobal Multi-Strategy Fund [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000898745_S000033960Memberdei_LegalEntityAxisexplicitMembernanafalse0Global Multi-Strategy Fund [Member]3false 2rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Global Multi-Strategy 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_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Under the Principal Investment Strategies heading, delete the paragraph that begins with "Equity Long/Short" 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;font-weight:bold;">Equity Long/Short. </font><font style="font-family:Arial;font-size:10pt;">This strategy provides long and short exposure to a diversified portfolio of U.S and non-U.S. equities which involves simultaneously investing in equities (i.e., investing long) the sub-advisor expects to increase in value (securities the sub-advisor believes are undervalued) and either selling equities (i.e., short sales or short selling) the sub-advisor expects to decrease in value (securities the sub-advisor believes are overvalued) or hedging equity market exposure in another way (i.e., by using derivatives such as futures or options). Long/short equity expresses industry views by emphasizing certain industries and it also seeks to exploit pricing inefficiencies between related equity securities. An example of exploiting pricing inefficiencies between related equity securities is building a portfolio containing long positions in the strongest companies of several industries and taking short positions in companies showing signs of weakness in the corresponding industries. This strategy has available two methods of analysis: fundamental analysis, a method of security analysis that involves examining a company's financial statements and operations, especially sales, earnings, products, management and competition and quantitative analysis, a method of security analysis that involves use of mathematical models to examine a company's measurable characteristics such as revenue, earnings, margins and market share.</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></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 ACP)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://xbrl.sec.gov/rr/role/RiskReturn15