2.4.0.8040000 - Disclosure - Risk/Return Detail Data {Elements}truetruefalse1false falsefalseD2013Q2June14http://www.sec.gov/CIK0000898745duration2013-06-14T00:00:002013-06-14T00:00:001true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:2false 2dei_DocumentTypedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Otherfalsefalsefalseus-types:SECReportItemTypenaThe type of document being provided (such as 10-K, 10-Q, N-1A, etc). The document type should be limited to the same value as the supporting SEC submission type. The acceptable values are as follows: S-1, S-3, S-4, S-11, F-1, F-3, F-4, F-9, F-10, 6-K, 8-K, 10, 10-K, 10-Q, 20-F, 40-F, N-1A, 485BPOS, NCSR, N-Q, and Other.No definition available.false0Document Type3false 2dei_DocumentPeriodEndDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-06-14falsefalsetruexbrli:dateItemTypedateThe end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements this will be the filing date. The format of the date is CCYY-MM-DD.No definition available.false0Document Period End Date4false 2dei_EntityRegistrantNamedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00PRINCIPAL FUNDS INCfalsefalsefalsexbrli:normalizedStringItemTypenormalizedstringThe exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false0Registrant Name5false 2dei_EntityCentralIndexKeydei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse000000898745falsefalsefalseus-types:centralIndexKeyItemTypenaA unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false0Central Index Key6false 2dei_AmendmentFlagdei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsexbrli:booleanItemTypenaIf the value is true, then the document as an amendment to previously-filed/accepted document.No definition available.false0Amendment Flag7false 2dei_DocumentCreationDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-06-14falsefalsetruexbrli:dateItemTypedateThe date the document was made available and submitted, in CCYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.No definition available.false0Document Creation Date8false 2dei_DocumentEffectiveDatedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002013-06-14falsefalsetruexbrli:dateItemTypedateThe date when a document, upon receipt and acceptance, becomes officially effective, in CCYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.No definition available.false0Document Effective Date9false 2rr_ProspectusDaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002012-12-28falsefalsetruexbrli:dateItemTypedateThe date of the prospectus.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 1 -Paragraph 3 -Subsection a false0Prospectus Date10false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2false truefalseD2013Q2June14_dei_DocumentInformationDocumentAxis_ck0000898745_PFIProspectusClassACPMemberhttp://www.sec.gov/CIK0000898745duration2013-06-14T00:00:002013-06-14T00:00:00falsefalsePFI Prospectus Class ACPdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldick0000898745_PFIProspectusClassACPMemberdei_DocumentInformationDocumentAxisexplicitMembernanafalse0PFI Prospectus Class ACP11true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:12false 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]13false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse3false 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_LegalEntityAxisexplicitMembernanafalse0PFI Prospectus Class ACP | Global Multi-Strategy Fund [Member]14true 1rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:15false 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]16false 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]17false 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 Detail DataUnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://xbrl.sec.gov/rr/role/RiskReturnDetailData117