2.2.0.25truefalse010000 - Document - Risk/Return Summary {Unlabeled}falsefalsetrue1falsefalseUSDtruefalse{dei_DocumentInformationDocumentAxis} : Janus Venture Fund 5/7/2010 - 5/6/2011 USD ($) $TwelveMonthsEnded_06May2011_S000010488_Memberhttp://www.sec.gov/CIK0000277751duration2010-05-07T00:00:002011-05-06T00:00:00falsefalsejif277751_S000010488Memberdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false0rr_RiskReturnHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00FUND SUMMARY Janus Venture FundfalsefalsefalsefalsefalseOtherxbrli: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 falsefalseRisk/Return [Heading]4false0rr_ObjectiveHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00INVESTMENT OBJECTIVEfalsefalsefalsefalsefalseOtherxbrli:stringItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a falsefalseObjective [Heading]5false0rr_ObjectivePrimaryTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Janus Venture Fund seeks capital appreciation.falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a falsefalseObjective, Primary [Text Block]6false0rr_ExpenseHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00FEES AND EXPENSES OF THE FUNDfalsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Summary Fee Table Includes the following information, in plain English under rule 421(d) under the Securities Act, after Item 2 Fees and expenses of the Fund This table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Shareholder Fees (fees paid directly from your investment) Example This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be You would pay the following expenses if you did not redeem your shares The Example does not reflect sales charges (loads) on reinvested dividends [and other distributions]. If these sales charges (loads) were included, your costs would be higher. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was __% of the average value of its whole portfolio. Instructions. A.3.instructions.6 New Funds. For purposes of this Item, a "New Fund" is a Fund that does not include in Form N-1A financial statements reporting operating results or that includes financial statements for the Fund's initial fiscal year reporting operating results for a period of 6 months or less. The following Instructions apply to New Funds.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph d -Subsection instructions falsefalseExpense [Heading]7false0rr_ExpenseNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00This table describes the fees and expenses that you may pay if you buy and hold Shares of the Fund. Each share class has different expenses, but represents an investment in the same Fund.falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown.The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph b -Subsection instructions falsefalseExpense Narrative [Text Block]8false0rr_ExpenseBreakpointDiscountsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00For Class A Shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or in other Janus mutual funds. More information about these and other discounts, as well as eligibility requirements for each share class, is available from your financial professional and in the &#8220;Purchases&#8221; section on page 26 of the Fund&#8217;s Prospectus and in the &#8220;Purchases&#8221; section on page 56 of the Fund&#8217;s Statement of Additional Information.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringInclude the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown.The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph b -Subsection instructions falsefalseExpense Breakpoint Discounts [Text]9false0rr_ShareholderFeesCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00SHAREHOLDER FEES (fees paid directly from your investment)falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringShareholder Fees (fees paid directly from your investment).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subsection table falsefalseShareholder Fees Caption [Text]10false0rr_ShareholderFeesTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ShareholderFees column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalse<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ShareholderFees column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsehttp://janus.com/role/ShareholderFeesfalsefalse020010 - Schedule - Shareholder Feestruefalsefalse1falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass A Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100475Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass A SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$2falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass C Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100476Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass C SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$3falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass S Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100478Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass S SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$4falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass I SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$1falseRowprimaryElement*4false0rr_ShareholderFeesColumnNamerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;Afalsefalsefalsetruefalse2falsefalsefalse00Class&#160;Cfalsefalsefalsetruefalse3falsefalsefalse00Class Sfalsefalsefalsetruefalse4falsefalsefalse00Class IfalsefalsefalsetruefalseOtherus-types:textBlockItemTypestringShareholder Fees (fees paid directly from your investment).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subsection table falsefalseShareholder Fees Column [Text]0rr_ShareholderFeesColumnNametruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;AClass&#160;Afalsefalsefalsetruefalse2falsefalsefalse00Class&#160;CClass&#160;Cfalsefalsefalsetruefalse3falsefalsefalse00Class SClass Sfalsefalsefalsetruefalse4falsefalsefalse00Class IClass IfalsefalsefalsetruefalseOthernanafalsefalseShareholder Fees Column [Text]2falseRowprimaryElement*5false0rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPricerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.05750.0575falsefalsefalsetruefalse2truetruetrue0.00000.0000falsefalsefalsetruefalse3truetruetrue0.00000.0000falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureMaximum Deferred Sales Charge (Load) (as a percentage of ____) A.3.instructions.2.a.i "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). A.3.instructions.2.a.ii If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 1 -Subsection table falsefalseMaximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price)0rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPricetruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.05750.0575falsefalsefalsetruefalse2truetruetrue0.00000.0000falsefalsefalsetruefalse3truetruetrue0.00000.0000falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOthernanafalsefalseMaximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price)3falseRowprimaryElement*6false0rr_MaximumDeferredSalesChargeOverOtherrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00000.0000falsefalsefalsetruefalse2truetruetrue0.01000.0100falsefalsefalsetruefalse3truetruetrue0.00000.0000falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureMaximum Deferred Sales Charge (Load) (as a percentage of ____) "Maximum Deferred Sales Charge (Load)" includes the maximum total deferred sales charge (load) payable upon redemption, in installments, or both, expressed as a percentage of the amount or amounts stated in response to Item 7(a), except that, for a sales charge (load) based on net asset value at the time of purchase, show the sales charge (load) as a percentage of the offering price at the time of purchase. A Fund may include in a footnote to the table, if applicable, a tabular presentation showing the amount of deferred sales charges (loads) over time or a narrative explanation of the sales charges (loads) (e.g., __% in the first year after purchase, declining to __% in the __ year and eliminated thereafter). If more than one type of sales charge (load) is imposed (e.g., a deferred sales charge (load) and a front-end sales charge (load)), the first caption in the table should read "Maximum Sales Charge (Load)" and show the maximum cumulative percentage. Show the percentage amounts and the terms of each sales charge (load) comprising that figure on separate lines below.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 2 -Subparagraph a -Clause i -Subsection instructions falsefalseMaximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds)0rr_MaximumDeferredSalesChargeOverOthertruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00000.0000falsefalsefalsetruefalse2truetruetrue0.01000.0100falsefalsefalsetruefalse3truetruetrue0.00000.0000falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOthernanafalsefalseMaximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds)43Shareholder Fees Janus Venture FundUnKnownUnKnownUnKnownUnKnownfalsetrueColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to ShareholderFeesData.No authoritative reference available.falsefalseShareholder Fees [Table]11false0rr_OperatingExpensesCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringAnnual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investment)Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 7 -Subsection table falsefalseOperating Expenses Caption [Text]12false0rr_AnnualFundOperatingExpensesTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AnnualFundOperatingExpenses column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalse<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AnnualFundOperatingExpenses column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsehttp://janus.com/role/AnnualFundOperatingExpensesfalsefalse020020 - Schedule - Annual Fund Operating Expensestruefalsefalse1falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass A Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100475Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass A SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$2falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass C Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100476Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass C SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$3falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass S Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100478Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass S SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$4falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass I SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$1falseRowprimaryElement*4false0rr_OperatingExpensesColumnNamerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;Afalsefalsefalsetruefalse2falsefalsefalse00Class&#160;Cfalsefalsefalsetruefalse3falsefalsefalse00Class&#160;Sfalsefalsefalsetruefalse4falsefalsefalse00Class&#160;IfalsefalsefalsetruefalseOtherus-types:textBlockItemTypestringAnnual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investment)Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 7 -Subsection table falsefalseOperating Expenses Column [Text]0rr_OperatingExpensesColumnNametruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;AClass&#160;Afalsefalsefalsetruefalse2falsefalsefalse00Class&#160;CClass&#160;Cfalsefalsefalsetruefalse3falsefalsefalse00Class&#160;SClass&#160;Sfalsefalsefalsetruefalse4falsefalsefalse00Class&#160;IClass&#160;IfalsefalsefalsetruefalseOthernanafalsefalseOperating Expenses Column [Text]2falseRowprimaryElement*5false0rr_ManagementFeesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00640.0064falsefalsefalsetruefalse2truetruetrue0.00640.0064falsefalsefalsetruefalse3truetruetrue0.00640.0064falsefalsefalsetruefalse4truetruetrue0.00640.0064falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureManagement Fees include investment advisory fees (including any fees based on the Fund's performance), any other management fees payable to the investment adviser or its affiliates, and administrative fees payable to the investment adviser or its affiliates that are not included as "Other Expenses."Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph a -Subsection instructions falsefalseManagement Fees0rr_ManagementFeesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00640.0064falsefalsefalsetruefalse2truetruetrue0.00640.0064falsefalsefalsetruefalse3truetruetrue0.00640.0064falsefalsefalsetruefalse4truetruetrue0.00640.0064falsefalsefalsetruefalseOthernanafalsefalseManagement Fees3falseRowprimaryElement*6false0rr_DistributionAndService12b1FeesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00250.0025falsefalsefalsetruefalse2truetruetrue0.010.01falsefalsefalsetruefalse3truetruetrue0.00250.0025falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureDistribution [and/or Service] (12b-1) Fees" include all distribution or other expenses incurred during the most recent fiscal year under a plan adopted pursuant to rule 12b-1 [17 CFR 270.12b-1]. Under an appropriate caption or a subcaption of "Other Expenses," disclose the amount of any distribution or similar expenses deducted from the Fund's assets other than pursuant to a rule 12b-1 plan.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 9 -Subsection table falsefalseDistribution/Service (12b-1) Fees0rr_DistributionAndService12b1FeesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00250.0025falsefalsefalsetruefalse2truetruetrue0.010.01falsefalsefalsetruefalse3truetruetrue0.00250.0025falsefalsefalsetruefalse4truetruetrue0.00000.0000falsefalsefalsetruefalseOthernanafalsefalseDistribution/Service (12b-1) Fees4falseRowprimaryElement*7false0rr_OtherExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00230.0023[2]falsefalsefalsetruefalse2truetruetrue0.00250.0025[2]falsefalsefalsetruefalse3truetruetrue0.00370.0037[2]falsefalsefalsetruefalse4truetruetrue0.00140.0014[2]falsefalsefalsetruefalseOtherrr:NonNegativePure4Typepure"Other Expenses" include all expenses not otherwise disclosed in the table that are deducted from the Fund's assets or charged to all shareholder accounts. The amount of expenses deducted from the Fund's assets are the amounts shown as expenses in the Fund's statement of operations (including increases resulting from complying with paragraph 2(g) of rule 6-07 of Regulation S-X [17 CFR 210.6-07]). "Other Expenses" do not include extraordinary expenses as determined under generally accepted accounting principles (see Accounting Principles Board Opinion No. 30). If extraordinary expenses were incurred that materially affected the Fund's "Other Expenses," disclose in a footnote to the table what "Other Expenses" would have been had the extraordinary expenses been included.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph c -Clause i -Subsection instructions falsefalseOther Expenses0rr_OtherExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse[1]1truetruetrue0.00230.0023falsefalsefalsetruefalse2truetruetrue0.00250.0025falsefalsefalsetruefalse3truetruetrue0.00370.0037falsefalsefalsetruefalse4truetruetrue0.00140.0014falsefalsefalsetruefalseOthernanafalsefalseOther Expenses5falseRowprimaryElement*8false0rr_Component1OtherExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00010.0001falsefalsefalsetruefalse2truetruetrue0.00010.0001falsefalsefalsetruefalse3truetruetrue0.00010.0001falsefalsefalsetruefalse4truetruetrue0.00010.0001falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureThe Fund may subdivide this caption into no more than three subcaptions that identify the largest expense or expenses comprising "Other Expenses," but must include a total of all "Other Expenses." Alternatively, the Fund may include the components of "Other Expenses" in a parenthetical to the caption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph c -Clause iii -Subsection instructions falsefalseShort Sale Dividend Expenses0rr_Component1OtherExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00010.0001falsefalsefalsetruefalse2truetruetrue0.00010.0001falsefalsefalsetruefalse3truetruetrue0.00010.0001falsefalsefalsetruefalse4truetruetrue0.00010.0001falsefalsefalsetruefalseOthernanafalsefalseShort Sale Dividend Expenses6falseRowprimaryElement*9false0rr_Component2OtherExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.00220.0022falsefalsefalsetruefalse2truetruetrue0.00240.0024falsefalsefalsetruefalse3truetruetrue0.00360.0036falsefalsefalsetruefalse4truetruetrue0.00130.0013falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureThe Fund may subdivide this caption into no more than three subcaptions that identify the largest expense or expenses comprising "Other Expenses," but must include a total of all "Other Expenses." Alternatively, the Fund may include the components of "Other Expenses" in a parenthetical to the caption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 10 -Subsection table falsefalseRemaining Other Expenses0rr_Component2OtherExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.00220.0022falsefalsefalsetruefalse2truetruetrue0.00240.0024falsefalsefalsetruefalse3truetruetrue0.00360.0036falsefalsefalsetruefalse4truetruetrue0.00130.0013falsefalsefalsetruefalseOthernanafalsefalseRemaining Other Expenses7falseRowprimaryElement*10false0rr_ExpensesOverAssetsrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.01120.0112[1]falsefalsefalsetruefalse2truetruetrue0.01890.0189[1]falsefalsefalsetruefalse3truetruetrue0.01260.0126[1]falsefalsefalsetruefalse4truetruetrue0.00780.0078[1]falsefalsefalsetruefalseOtherrr:NonNegativePure4TypepureTotal Annual Fund Operating Expenses. If the Fund is a Feeder Fund, reflect the aggregate expenses of the Feeder Fund and the Master Fund in a single fee table using the captions provided. In a footnote to the fee table, state that the table and Example reflect the expenses of both the Feeder and Master Funds. If the prospectus offers more than one Class of a Multiple Class Fund or more than one Feeder Fund that invests in the same Master Fund, provide a separate response for each Class or Feeder Fund. Base the percentages of "Annual Fund Operating Expenses" on amounts incurred during the Fund's most recent fiscal year, but include in expenses amounts that would have been incurred absent expense reimbursement or fee waiver arrangements. If the Fund has changed its fiscal year and, as a result, the most recent fiscal year is less than three months, use the fiscal year prior to the most recent fiscal year as the basis for determining "Annual Fund Operating Expenses."Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subparagraph d -Subsection instructions falsefalseTotal Annual Fund Operating Expenses0rr_ExpensesOverAssetstruefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse[2]1truetruetrue0.01120.0112falsefalsefalsetruefalse2truetruetrue0.01890.0189falsefalsefalsetruefalse3truetruetrue0.01260.0126falsefalsefalsetruefalse4truetruetrue0.00780.0078falsefalsefalsetruefalseOthernanafalsefalseTotal Annual Fund Operating Expenses1Other Expenses are based on the estimated expenses that each class of Shares expects to incur during its initial fiscal period.2Janus Capital has contractually agreed to waive the Fund's total annual fund operating expenses (excluding the distribution and shareholder servicing fees - applicable to Class A Shares, Class C Shares, and Class S Shares; administrative services fees payable pursuant to the Transfer Agency Agreement - applicable to Class S Shares; brokerage commissions; interest; dividends; taxes; and extraordinary expenses including, but not limited to, acquired fund fees and expenses) to 1.05% until at least February 1, 2012. The contractual waiver may be terminated or modified prior to this date only at the discretion of the Board of Trustees.47Annual Fund Operating Expenses Janus Venture FundUnKnownUnKnownUnKnownUnKnownfalsetrueColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to OperatingExpensesData.No authoritative reference available.falsefalseAnnual Fund Operating Expenses [Table]13false0rr_ExpenseExampleHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00EXAMPLE:falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringHeading for Expense Example.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subsection instructions falsefalseExpense Example [Heading]14false0rr_ExpenseExampleNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The following Example is based on expenses without waivers. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThe Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 1 -Subsection example falsefalseExpense Example Narrative [Text Block]15false0rr_ExpenseExampleByYearHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Example assumes that you invest $10,000 in the Fund for the time periods indicated and reinvest all dividends and distributions. The Example also assumes that your investment has a 5% return each year and that the Fund&#8217;s operating expenses without waivers remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example by Year [Heading]16false0rr_ExpenseExampleByYearCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00If Shares are redeemed:falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example by, Year, Caption [Text]17false0rr_ExpenseExampleWithRedemptionTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ExpenseExample column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalse<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ExpenseExample column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>truehttp://janus.com/role/ExpenseExamplefalsefalse020030 - Schedule - Expense Example {Transposed}truefalsefalse1falseColumnprimaryElement*4false0rr_ExpenseExampleByYearColumnNamerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class A Sharesfalsefalsefalsetruefalse2falsefalsefalse00Class C Sharesfalsefalsefalsetruefalse3falsefalsefalse00Class&#160;S Sharesfalsefalsefalsetruefalse4falsefalsefalse00Class&#160;I SharesfalsefalsefalsetruefalseOtherus-types:textBlockItemTypestringThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalseExpense Example, By Year, Column [Text]falseUSDfalsefalse$2falseColumnprimaryElement*5false0rr_ExpenseExampleYear01rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue683683falsefalsefalsetruefalse2truefalsetrue292292falsefalsefalsetruefalse3truefalsetrue128128falsefalsefalsetruefalse4truefalsetrue8080falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subsection instructions falsefalse1 YearfalseUSDfalsefalse$3falseColumnprimaryElement*6false0rr_ExpenseExampleYear03rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue911911falsefalsefalsetruefalse2truefalsetrue594594falsefalsefalsetruefalse3truefalsetrue400400falsefalsefalsetruefalse4truefalsetrue249249falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalse3 YearsfalseUSDfalsefalse$4falseColumnprimaryElement*7false0rr_ExpenseExampleYear05rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue11561156falsefalsefalsetruefalse2truefalsetrue10211021falsefalsefalsetruefalse3truefalsetrue692692falsefalsefalsetruefalse4truefalsetrue433433falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalse5 YearsfalseUSDfalsefalse$5falseColumnprimaryElement*8false0rr_ExpenseExampleYear10rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue18601860falsefalsefalsetruefalse2truefalsetrue22122212falsefalsefalsetruefalse3truefalsetrue15231523falsefalsefalsetruefalse4truefalsetrue966966falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryThe Example assumes that you invest $10,000 in the Fund for the time periods indicated and then you redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return per year and that the Fund's operating expenses remained the same. Although your actual costs may be higher or lower.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 1 -Subparagraph 2 -Subsection example falsefalse10 YearsfalseUSDfalsefalse$1falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass A Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100475Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass A SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class A SharesClass A Sharesfalsefalsefalsetruefalse2truefalsetrue683683falsefalsefalsetruefalse3truefalsetrue911911falsefalsefalsetruefalse4truefalsetrue11561156falsefalsefalsetruefalse5truefalsetrue18601860falsefalsefalsetruefalseOthernanafalsefalseClass A Shares2falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass C Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100476Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass C SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class C SharesClass C Sharesfalsefalsefalsetruefalse2truefalsetrue292292falsefalsefalsetruefalse3truefalsetrue594594falsefalsefalsetruefalse4truefalsetrue10211021falsefalsefalsetruefalse5truefalsetrue22122212falsefalsefalsetruefalseOthernanafalsefalseClass C Shares3falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass S Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100478Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass S SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;S SharesClass&#160;S Sharesfalsefalsefalsetruefalse2truefalsetrue128128falsefalsefalsetruefalse3truefalsetrue400400falsefalsefalsetruefalse4truefalsetrue692692falsefalsefalsetruefalse5truefalsetrue15231523falsefalsefalsetruefalseOthernanafalsefalseClass S Shares4falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass I SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;I SharesClass&#160;I Sharesfalsefalsefalsetruefalse2truefalsetrue8080falsefalsefalsetruefalse3truefalsetrue249249falsefalsefalsetruefalse4truefalsetrue433433falsefalsefalsetruefalse5truefalsetrue966966falsefalsefalsetruefalseOthernanafalsefalseClass I Shares54Expense Example Janus Venture Fund (USD $)UnKnownUnKnownUnKnownUnKnownfalsetrueColumnprimaryElement*RowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to ExpenseExample.No authoritative reference available.falsefalseExpense Example, With Redemption [Table]18false0rr_ExpenseExampleNoRedemptionByYearCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00If Shares are not redeemed:falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 2 -Subparagraph 1 -Subsection example falsefalseExpense Example, No Redemption, By Year, Caption [Text]19false0rr_ExpenseExampleNoRedemptionTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ExpenseExampleNoRedemption column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalse<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/ExpenseExampleNoRedemption column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>truehttp://janus.com/role/ExpenseExampleNoRedemptionfalsefalse020040 - Schedule - Expense Example, No Redemption {Transposed}truefalsefalse1falseColumnprimaryElement*4false0rr_ExpenseExampleNoRedemptionByYearColumnNamerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class A Sharesfalsefalsefalsetruefalse2falsefalsefalse00Class C Sharesfalsefalsefalsetruefalse3falsefalsefalse00Class&#160;S Sharesfalsefalsefalsetruefalse4falsefalsefalse00Class&#160;I SharesfalsefalsefalsetruefalseOtherus-types:textBlockItemTypestringYou would pay the following expenses if you did not redeem your shares.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 2 -Subparagraph 1 -Subsection example falsefalseExpense Example, No Redemption, By Year, Column [Text]falseUSDfalsefalse$2falseColumnprimaryElement*5false0rr_ExpenseExampleNoRedemptionYear01rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue683683falsefalsefalsetruefalse2truefalsetrue192192falsefalsefalsetruefalse3truefalsetrue128128falsefalsefalsetruefalse4truefalsetrue8080falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 2 -Subparagraph 1 -Subsection example falsefalse1 YearfalseUSDfalsefalse$3falseColumnprimaryElement*6false0rr_ExpenseExampleNoRedemptionYear03rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue911911falsefalsefalsetruefalse2truefalsetrue594594falsefalsefalsetruefalse3truefalsetrue400400falsefalsefalsetruefalse4truefalsetrue249249falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 2 -Subparagraph 1 -Subsection example falsefalse3 YearsfalseUSDfalsefalse$4falseColumnprimaryElement*7false0rr_ExpenseExampleNoRedemptionYear05rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue11561156falsefalsefalsetruefalse2truefalsetrue10211021falsefalsefalsetruefalse3truefalsetrue692692falsefalsefalsetruefalse4truefalsetrue433433falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subparagraph f -Subsection instructions falsefalse5 YearsfalseUSDfalsefalse$5falseColumnprimaryElement*8false0rr_ExpenseExampleNoRedemptionYear10rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsetrue18601860falsefalsefalsetruefalse2truefalsetrue22122212falsefalsefalsetruefalse3truefalsetrue15231523falsefalsefalsetruefalse4truefalsetrue966966falsefalsefalsetruefalseMonetaryrr:NonNegativeMonetaryTypemonetaryYou would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 4 -Subparagraph f -Subsection instructions falsefalse10 YearsfalseUSDfalsefalse$1falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass A Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100475Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass A SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class A SharesClass A Sharesfalsefalsefalsetruefalse2truefalsetrue683683falsefalsefalsetruefalse3truefalsetrue911911falsefalsefalsetruefalse4truefalsetrue11561156falsefalsefalsetruefalse5truefalsetrue18601860falsefalsefalsetruefalseOthernanafalsefalseClass A Shares2falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass C Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100476Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass C SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class C SharesClass C Sharesfalsefalsefalsetruefalse2truefalsetrue192192falsefalsefalsetruefalse3truefalsetrue594594falsefalsefalsetruefalse4truefalsetrue10211021falsefalsefalsetruefalse5truefalsetrue22122212falsefalsefalsetruefalseOthernanafalsefalseClass C Shares3falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass S Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100478Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass S SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;S SharesClass&#160;S Sharesfalsefalsefalsetruefalse2truefalsetrue128128falsefalsefalsetruefalse3truefalsetrue400400falsefalsefalsetruefalse4truefalsetrue692692falsefalsefalsetruefalse5truefalsetrue15231523falsefalsefalsetruefalseOthernanafalsefalseClass S Shares4falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass I SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso421700truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Class&#160;I SharesClass&#160;I Sharesfalsefalsefalsetruefalse2truefalsetrue8080falsefalsefalsetruefalse3truefalsetrue249249falsefalsefalsetruefalse4truefalsetrue433433falsefalsefalsetruefalse5truefalsetrue966966falsefalsefalsetruefalseOthernanafalsefalseClass I Shares54Expense Example, No Redemption Janus Venture Fund (USD $)UnKnownUnKnownUnKnownUnKnownfalsetrueColumnprimaryElement*RowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to ExpenseExampleNoRedemption.No authoritative reference available.falsefalseExpense Example, No Redemption [Table]20false0rr_PortfolioTurnoverHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Portfolio Turnover:falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 5 -Subsection instructions falsefalsePortfolio Turnover [Heading]21false0rr_PortfolioTurnoverTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221; its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal period, the Fund&#8217;s portfolio turnover rate was 64% of the average value of its portfolio.falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDisclose the portfolio turnover rate provided in response to Item 14(a) for the most recent fiscal year (or for such shorter period as the Fund has been in operation). Disclose the period for which the information is provided if less than a full fiscal year. A Fund that is a Money Market Fund may omit the portfolio turnover information required by this Item.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 3 -Paragraph 3 -Subsection example falsefalsePortfolio Turnover [Text Block]22false0rr_StrategyHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00PRINCIPAL INVESTMENT STRATEGIESfalsefalsefalsefalsefalseOtherxbrli: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 falsefalseStrategy [Heading]23false0rr_StrategyNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p>The Fund pursues its investment objective by investing at least 50% of its equity assets in small-sized companies. The Fund may also invest in larger companies with strong growth potential or relatively well-known and large companies with potential for capital appreciation. Small-sized companies are defined by the portfolio managers as those companies whose market capitalization falls within the range of companies in the Russell 2000^&#174; Growth Index. Market capitalization is a commonly used measure of the size and value of a company. The market capitalizations within the index will vary, but as of September 30, 2010, they ranged from approximately $2 million to $3.2 billion. Companies whose capitalization or revenues fall outside these ranges after the Fund&#8217;s initial purchase continue to be considered small-sized.</p><p>The portfolio managers apply a &#8220;bottom up&#8221; approach in choosing investments. In other words, the portfolio managers look at companies one at a time to determine if a company is an attractive investment opportunity and if it is consistent with the Fund&#8217;s investment policies.</p><p>The Fund may invest in foreign equity and debt securities, which may include investments in emerging markets.</p><p>The Fund may lend portfolio securities on a short-term or long-term basis, in an amount equal to up to 1/3 of its total assets as determined at the time of the loan origination.</p>falsefalsefalsefalsefalseOtherus-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 falsefalseStrategy Narrative [Text Block]24false0rr_RiskHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00PRINCIPAL INVESTMENT RISKSfalsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNarrative Risk Disclosure.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 1 -Subsection b falsefalseRisk [Heading]25false0rr_RiskNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p>The biggest risk is that the Fund&#8217;s returns will vary, and you could lose money. The Fund is designed for long-term investors seeking an equity portfolio, including common stocks. Common stocks tend to be more volatile than many other investment choices.</p><p><b><i>Market Risk.</i></b> The value of the Fund&#8217;s portfolio may decrease if the value of an individual company or multiple companies in the portfolio decreases or if the portfolio managers&#8217; belief about a company&#8217;s intrinsic worth is incorrect. Further, regardless of how well individual companies perform, the value of the Fund&#8217;s portfolio could also decrease if there are deteriorating economic or market conditions. It is important to understand that the value of your investment may fall, sometimes sharply, in response to changes in the market, and you could lose money.</p><p><b><i>Small-Sized Companies Risk.</i></b> The Fund&#8217;s investments in securities issued by small-sized companies, which tend to be smaller, start-up companies offering emerging products or services, may involve greater risks than are customarily associated with larger, more established companies. Securities issued by small-sized companies tend to be more volatile and somewhat more speculative than securities issued by larger or more established companies and may underperform as compared to the securities of larger companies.</p><p><b><i>Foreign Exposure Risk.</i></b> The Fund may have significant exposure to foreign markets, including emerging markets, which can be more volatile than the U.S. markets. As a result, its returns and net asset value may be affected to a large degree by fluctuations in currency exchange rates or political or economic conditions in a particular country. A market swing in one or more countries or regions where the Fund has invested a significant amount of its assets may have a greater effect on the Fund&#8217;s performance than it would in a more geographically diversified portfolio. The Fund&#8217;s investments in emerging market countries may involve risks greater than, or in addition to, the risks of investing in more developed countries.</p><p><b><i>Growth Securities Risk.</i></b> Securities of companies perceived to be &#8220;growth&#8221; companies may be more volatile than other stocks and may involve special risks. The price of a &#8220;growth&#8221; security may be impacted if the company does not realize its anticipated potential or if there is a shift in the market to favor other types of securities.</p><p><b><i>Securities Lending Risk.</i></b> The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions. There is the risk that when portfolio securities are lent, the securities may not be returned on a timely basis, and the Fund may experience delays and costs in recovering the security or gaining access to the collateral provided to the Fund to collateralize the loan. If the Fund is unable to recover a security on loan, the Fund may use the collateral to purchase replacement securities in the market. There is a risk that the value of the collateral could decrease below the cost of the replacement security by the time the replacement investment is made, resulting in a loss to the Fund.</p><p><i>An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</i></p>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringNarrative Risk Disclosure. A Fund may, in responding to this Item, describe the types of investors for whom the Fund is intended or the types of investment goals that may be consistent with an investment in the Fund.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 1 -Subparagraph i -Clause instruction -Subsection b falsefalseRisk Narrative [Text Block]26false0rr_BarChartAndPerformanceTableHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00PERFORMANCE INFORMATIONfalsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Bar Chart and Table.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subsection b falsefalseBar Chart and Performance Table [Heading]27false0rr_PerformanceNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p>The following information provides some indication of the risks of investing in the Fund by showing how the Fund&#8217;s performance has varied over time. Class T Shares (formerly named Class J Shares, the initial share class) of the Fund commenced operations with the Fund&#8217;s inception. Class A Shares, Class C Shares, Class S Shares, and Class I Shares of the Fund commenced operations on May 6, 2011.</p> <p>&#8226; The performance shown for Class A Shares, Class C Shares, and Class S Shares for periods prior to December 31, 2010, reflects the performance of the Fund&#8217;s former Class J Shares, calculated using the fees and expenses of each respective share class, without the effect of any fee and expense limitations or waivers.</p> <p>&#8226; The performance shown for Class I Shares for periods prior to December 31, 2010, reflects the performance of the Fund&#8217;s former Class J Shares, calculated using the fees and expenses of Class J Shares, without the effect of any fee and expense limitations or waivers.</p> <p>If Class A Shares, Class C Shares, Class S Shares, and Class I Shares of the Fund had been available during periods prior to December 31, 2010, the performance shown for each respective share class may have been different.</p> <p>The bar chart depicts the change in performance from year to year during the periods indicated. The bar chart figures do not include any applicable sales charges that an investor may pay when they buy or sell Class A Shares or Class C Shares of the Fund. If sales charges were included, the returns would be lower. The table compares the Fund&#8217;s average annual returns for the periods indicated to broad-based securities market indices. The indices are not actively managed and are not available for direct investment. All figures assume reinvestment of dividends and distributions.</p> <p><i>The Fund&#8217;s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. Updated performance information is available at janus.com/advisor/mutual-funds or by calling 1-877-335-2687.</i></p>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringRisk/Return Bar Chart and Table.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subsection b falsefalsePerformance Narrative [Text Block]28false0rr_BarChartHeadingrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Annual Total Returns for Class I Shares (calendar year-end)falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringRisk/Return Bar Chart and Table.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subsection b falsefalseBar Chart [Heading]29false0rr_BarChartTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AnnualTotalReturnsBarChart column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalseBarChart1.jpg<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AnnualTotalReturnsBarChart column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsehttp://janus.com/role/AnnualTotalReturnsBarChartfalsefalse020050 - Schedule - Annual Total Returns (Bar Chart)truefalsefalse1falseColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundClass I SharesUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170falseUSDfalsefalse$1falseRowprimaryElement*4false0rr_AnnualReturn2001rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse-0.1193-0.1193falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20010rr_AnnualReturn2001truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.1193-0.1193falsefalsefalsetruefalseOthernanafalsefalse20012falseRowprimaryElement*5false0rr_AnnualReturn2002rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse-0.2724-0.2724falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20020rr_AnnualReturn2002truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.2724-0.2724falsefalsefalsetruefalseOthernanafalsefalse20023falseRowprimaryElement*6false0rr_AnnualReturn2003rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.55750.5575falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a -Subsection b falsefalse20030rr_AnnualReturn2003truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.55750.5575falsefalsefalsetruefalseOthernanafalsefalse20034falseRowprimaryElement*7false0rr_AnnualReturn2004rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.17560.1756falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a -Subsection b falsefalse20040rr_AnnualReturn2004truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.17560.1756falsefalsefalsetruefalseOthernanafalsefalse20045falseRowprimaryElement*8false0rr_AnnualReturn2005rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.01550.0155falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20050rr_AnnualReturn2005truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.01550.0155falsefalsefalsetruefalseOthernanafalsefalse20056falseRowprimaryElement*9false0rr_AnnualReturn2006rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.23580.2358falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20060rr_AnnualReturn2006truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.23580.2358falsefalsefalsetruefalseOthernanafalsefalse20067falseRowprimaryElement*10false0rr_AnnualReturn2007rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.16360.1636falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a -Subsection b falsefalse20070rr_AnnualReturn2007truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.16360.1636falsefalsefalsetruefalseOthernanafalsefalse20078falseRowprimaryElement*11false0rr_AnnualReturn2008rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse-0.5143-0.5143falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20080rr_AnnualReturn2008truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse-0.5143-0.5143falsefalsefalsetruefalseOthernanafalsefalse20089falseRowprimaryElement*12false0rr_AnnualReturn2009rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.54500.5450falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 3 -Exhibit a -Subsection b falsefalse20090rr_AnnualReturn2009truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.54500.5450falsefalsefalsetruefalseOthernanafalsefalse200910falseRowprimaryElement*13false0rr_AnnualReturn2010rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruefalse0.26960.2696falsefalsefalsetruefalseOtherxbrli:pureItemTypepureIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalse20100rr_AnnualReturn2010truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruefalse0.26960.2696falsefalsefalsetruefalseOthernanafalsefalse2010110Annual Total Returns (Bar Chart) UnKnownUnKnownUnKnownUnKnownfalsetrueColumnperiodPeriod*Columndei_DocumentInformationDocumentAxisAxis*Columnrr_ProspectusShareClassAxisAxis*ColumnunitUnit*RowprimaryElement*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to BarChartData.No authoritative reference available.falsefalseBar Chart [Table]30false0rr_BarChartClosingTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p>Best Quarter:&#160;&#160;Second Quarter 2009&#160;&#160;28.30%&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Worst Quarter:&#160;&#160;Fourth Quarter 2008&#160;&#160;-28.61%</p>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalseBar Chart Closing [Text Block]31false0rr_YearToDateReturnLabelrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Fund&#8217;s year-to-date return as of the calendar quarter ended March&#160;31, 2011 was 8.84%.falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringIf the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph ii -Subsection b falsefalseYear to Date Return, Label32false0rr_AverageAnnualReturnCaptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Average Annual Total Returns (periods ended 12/31/10)falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 5 -Subsection b falsefalseCaption33false0rr_PerformanceTableTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AverageAnnualTotalReturns column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>falsefalse<div> &lt;div style="display:none;"&gt;~ http://janus.com/role/AverageAnnualTotalReturns column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_DocumentInformationDocumentAxis compact jif277751-20110506_Member * row dei_LegalEntityAxis compact jif277751-20110506_Member * ~&lt;/div&gt; </div>truehttp://janus.com/role/AverageAnnualTotalReturnsfalsefalse020060 - Schedule - Average Annual Total Returns {Transposed}truefalsefalse1falseColumnprimaryElement*4false0rr_AverageAnnualReturnColumnNamerrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;A Sharesfalsefalsefalsetruefalse2falsetruefalse00Class&#160;C Sharesfalsefalsefalsetruefalse3falsetruefalse00Class&#160;S Sharesfalsefalsefalsetruefalse4falsetruefalse00Class&#160;I Sharesfalsefalsefalsetruefalse5falsetruefalse00Class&#160;I Sharesfalsefalsefalsetruefalse6falsetruefalse00Class&#160;I Sharesfalsefalsefalsetruefalse7falsetruefalse00falsefalsefalsetruefalse8falsetruefalse00falsefalsefalsetruefalseOtherus-types:textBlockItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 1 -Subsection b falsefalseColumnfalseUSDfalsefalse$2falseColumnprimaryElement*5false0rr_AverageAnnualReturnLabelrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Return Before Taxes[1]falsefalsefalsetruefalse2falsetruefalse00Return Before Taxes[3]falsefalsefalsetruefalse3falsetruefalse00Return Before Taxesfalsefalsefalsetruefalse4falsetruefalse00Return Before Taxesfalsefalsefalsetruefalse5falsetruefalse00Return After Taxes on Distributionsfalsefalsefalsetruefalse6falsetruefalse00Return After Taxes on Distributions and Sale of Fund Shares[2]falsefalsefalsetruefalse7falsetruefalse00Russell 2000^&#174; Growth Indexfalsefalsefalsetruefalse8falsetruefalse00Russell 2000^&#174; IndexfalsefalsefalsetruefalseOtherxbrli:stringItemTypestringThis item represents Average Anuual Total Returns. If a Multiple Class Fund offers a Class in the prospectus that converts into another Class after a stated period, compute average annual total returns in the table by using the returns of the other Class for the period after conversion.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalseLabelfalseUSDfalsefalse$3falseColumnprimaryElement*6false0rr_IndexNoDeductionForFeesExpensesTaxesrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsetruefalse7falsefalsefalse00(reflects no deduction for expenses, fees, or taxes)falsefalsefalsetruefalse8falsefalsefalse00(reflects no deduction for expenses, fees, or taxes)falsefalsefalsetruefalseOtherxbrli:stringItemTypestringThe Performance Table includes a parenthetical, indicating that the Index "(reflects no deduction for fees, expenses or taxes)". This tag is used when this is reflected in a footnote.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 5 -Subsection b falsefalseIndex No Deduction for Fees, Expenses, Taxes [Text]falseUSDfalsefalse$4falseColumnprimaryElement*7false0rr_AverageAnnualReturnYear01rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.26740.2674falsefalsefalsetruefalse2truetruetrue0.26180.2618falsefalsefalsetruefalse3truetruetrue0.26600.2660falsefalsefalsetruefalse4truetruetrue0.26960.2696falsefalsefalsetruefalse5truetruetrue0.26960.2696falsefalsefalsetruefalse6truetruetrue0.17520.1752falsefalsefalsetruefalse7truetruetrue0.29090.2909falsefalsefalsetruefalse8truetruetrue0.26850.2685falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalse1 YearfalseUSDfalsefalse$5falseColumnprimaryElement*8false0rr_AverageAnnualReturnYear05rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.06340.0634falsefalsefalsetruefalse2truetruetrue0.05900.0590falsefalsefalsetruefalse3truetruetrue0.06240.0624falsefalsefalsetruefalse4truetruetrue0.06500.0650falsefalsefalsetruefalse5truetruetrue0.05380.0538falsefalsefalsetruefalse6truetruetrue0.05490.0549falsefalsefalsetruefalse7truetruetrue0.05300.0530falsefalsefalsetruefalse8truetruetrue0.04470.0447falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalse5 YearsfalseUSDfalsefalse$6falseColumnprimaryElement*9false0rr_AverageAnnualReturnYear10rrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truetruetrue0.04830.0483falsefalsefalsetruefalse2truetruetrue0.04310.0431falsefalsefalsetruefalse3truetruetrue0.04710.0471falsefalsefalsetruefalse4truetruetrue0.05020.0502falsefalsefalsetruefalse5truetruetrue0.04390.0439falsefalsefalsetruefalse6truetruetrue0.04310.0431falsefalsefalsetruefalse7truetruetrue0.03780.0378falsefalsefalsetruefalse8truetruetrue0.06330.0633falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalse10 YearsfalseUSDfalsefalse$7falseColumnprimaryElement*10false0rr_AverageAnnualReturnSinceInceptionrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truetruetrue0.11750.1175falsefalsefalsetruefalse2truetruetrue0.11100.1110falsefalsefalsetruefalse3truetruetrue0.11640.1164falsefalsefalsetruefalse4truetruetrue0.11920.1192falsefalsefalsetruefalse5truetruetrue0.09730.0973falsefalsefalsetruefalse6truetruetrue0.09640.0964falsefalsefalsetruefalse7truetruetrue0.07370.0737falsefalsefalsetruefalse8truetruetrue0.09500.0950falsefalsefalsetruefalseOtherxbrli:pureItemTypepureReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iii -Clause 1 -Exhibit 2 -Subsection b falsefalseSince InceptionfalseUSDfalsefalse$8falseColumnprimaryElement*11false0rr_AverageAnnualReturnInceptionDaterrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse001985-04-30falsefalsetruetruefalse2falsetruefalse001985-04-30falsefalsetruetruefalse3falsetruefalse001985-04-30falsefalsetruetruefalse4falsetruefalse001985-04-30falsefalsetruetruefalse5falsetruefalse001985-04-30falsefalsetruetruefalse6falsetruefalse001985-04-30falsefalsetruetruefalse7falsetruefalse001985-04-30falsefalsetruetruefalse8falsetruefalse001985-04-30falsefalsetruetruefalseOtherxbrli:dateItemTypedateReturn Before Taxes.Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph instructions -Clause 4 -Subsection b falsefalseInception DatefalseUSDfalsefalse$1falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn Before Taxesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_ReturnBeforeTaxMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn Before TaxesClass I SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;I SharesClass&#160;I Sharesfalsefalsefalsetruefalse2falsetruefalse00Return Before TaxesReturn Before Taxesfalsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.26960.2696falsefalsefalsetruefalse5truetruetrue0.06500.0650falsefalsefalsetruefalse6truetruetrue0.05020.0502falsefalsefalsetruefalse7truetruetrue0.11920.1192falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn Before Taxes Class I Shares2falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn Before Taxesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_ReturnBeforeTaxMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass A Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100475Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn Before TaxesClass A SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;A SharesClass&#160;A Sharesfalsefalsefalsetruefalse2falsetruefalse00Return Before TaxesReturn Before Taxes[1]falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.26740.2674falsefalsefalsetruefalse5truetruetrue0.06340.0634falsefalsefalsetruefalse6truetruetrue0.04830.0483falsefalsefalsetruefalse7truetruetrue0.11750.1175falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn Before Taxes Class A Shares3falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn Before Taxesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_ReturnBeforeTaxMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass C Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100476Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn Before TaxesClass C SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;C SharesClass&#160;C Sharesfalsefalsefalsetruefalse2falsetruefalse00Return Before TaxesReturn Before Taxes[2]falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.26180.2618falsefalsefalsetruefalse5truetruetrue0.05900.0590falsefalsefalsetruefalse6truetruetrue0.04310.0431falsefalsefalsetruefalse7truetruetrue0.11100.1110falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn Before Taxes Class C Shares4falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn Before Taxesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_ReturnBeforeTaxMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass S Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100478Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn Before TaxesClass S SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;S SharesClass&#160;S Sharesfalsefalsefalsetruefalse2falsetruefalse00Return Before TaxesReturn Before Taxesfalsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.26600.2660falsefalsefalsetruefalse5truetruetrue0.06240.0624falsefalsefalsetruefalse6truetruetrue0.04710.0471falsefalsefalsetruefalse7truetruetrue0.11640.1164falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn Before Taxes Class S Shares5falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn After Taxes on Distributionsrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldirr_AfterTaxesOnDistributionsMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn After Taxes on DistributionsClass I SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;I SharesClass&#160;I Sharesfalsefalsefalsetruefalse2falsetruefalse00Return After Taxes on DistributionsReturn After Taxes on Distributionsfalsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.26960.2696falsefalsefalsetruefalse5truetruetrue0.05380.0538falsefalsefalsetruefalse6truetruetrue0.04390.0439falsefalsefalsetruefalse7truetruetrue0.09730.0973falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn After Taxes on Distributions Class I Shares6falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseReturn After Taxes on Distributions and Sale of Fund Sharesrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldirr_AfterTaxesOnDistributionsAndSalesMemberrr_PerformanceMeasureAxisexplicitMemberfalsefalseClass I Sharesrr_ProspectusShareClassAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_C000100477Memberrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundReturn After Taxes on Distributions and Sale of Fund SharesClass I SharesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsetruefalse00Class&#160;I SharesClass&#160;I Sharesfalsefalsefalsetruefalse2falsetruefalse00Return After Taxes on Distributions and Sale of Fund SharesReturn After Taxes on Distributions and Sale of Fund Shares[3]falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsefalsefalse4truetruetrue0.17520.1752falsefalsefalsetruefalse5truetruetrue0.05490.0549falsefalsefalsetruefalse6truetruetrue0.04310.0431falsefalsefalsetruefalse7truetruetrue0.09640.0964falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseReturn After Taxes on Distributions and Sale of Fund Shares Class I Shares7falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseRussell 2000 Growth Indexrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_RussellTwoThousandGrowthIndexMemberrr_PerformanceMeasureAxisexplicitMembertruefalseShare Classesrr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundRussell 2000 Growth IndexShare ClassesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsetruefalse00Russell 2000^&#174; Growth IndexRussell 2000&#174; Growth Indexfalsefalsefalsetruefalse3falsefalsefalse00(reflects no deduction for expenses, fees, or taxes)(reflects no deduction for expenses, fees, or taxes)falsefalsefalsetruefalse4truetruetrue0.29090.2909falsefalsefalsetruefalse5truetruetrue0.05300.0530falsefalsefalsetruefalse6truetruetrue0.03780.0378falsefalsefalsetruefalse7truetruetrue0.07370.0737falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseRussell 2000 Growth Index8falseRowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*duration2010-05-07T00:00:002011-05-06T00:00:00falsefalseJanus Venture Funddei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_S000010488Memberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseRussell 2000 Indexrr_PerformanceMeasureAxisxbrldihttp://xbrl.org/2006/xbrldijif277751_RussellTwoThousandIndexMemberrr_PerformanceMeasureAxisexplicitMembertruefalseShare Classesrr_ProspectusShareClassAxisrr_ShareClassDomainrr_ProspectusShareClassAxisexplicitMemberJanus Venture FundRussell 2000 IndexShare ClassesStandard00truefalsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsetruefalse00Russell 2000^&#174; IndexRussell 2000&#174; Indexfalsefalsefalsetruefalse3falsefalsefalse00(reflects no deduction for expenses, fees, or taxes)(reflects no deduction for expenses, fees, or taxes)falsefalsefalsetruefalse4truetruetrue0.26850.2685falsefalsefalsetruefalse5truetruetrue0.04470.0447falsefalsefalsetruefalse6truetruetrue0.06330.0633falsefalsefalsetruefalse7truetruetrue0.09500.0950falsefalsefalsetruefalse8falsetruefalse001985-04-301985-04-30falsefalsetruetruefalseOthernanafalsefalseRussell 2000 Index1Calculated assuming maximum permitted sales loads.2The one year return is calculated to include the contingent deferred sales charge.3If the Fund incurs a loss, which generates a tax benefit, the Return After Taxes on Distributions and Sale of Fund Shares may exceed the Fund's other return figures.88Average Annual Total Returns Janus Venture FundUnKnownUnKnownUnKnownUnKnownfalsetrueColumnprimaryElement*RowperiodPeriod*Rowdei_DocumentInformationDocumentAxisAxis*Rowrr_PerformanceMeasureAxisAxis*Rowrr_ProspectusShareClassAxisAxis*RowunitUnit*falsefalsefalseOtherus-types:textBlockItemTypestringContains a command for the SEC Viewer for the role corresponding to PerformanceTableData.No authoritative reference available.falsefalsePerformance [Table]34false0rr_PerformanceTableNarrativeTextBlockrrfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p>After-tax returns are calculated using distributions for the Fund&#8217;s Class T Shares (formerly named Class J Shares, the initial share class). After-tax returns are calculated using the historically highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your individual tax situation and may differ from those shown in the preceding table. The after-tax return information shown above does not apply to Fund shares held through a tax-deferred account, such as a 401(k) plan or an IRA.</p><p>After-tax returns are only shown for Class I Shares of the Fund. After-tax returns for the other classes of Shares will vary from those shown for Class I Shares due to varying sales charges (as applicable), fees, and expenses among the classes.</p>falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringIf the Fund has annual returns for at least one calendar year, provide a table showing the Fund's (A) average annual total return; (B) average annual total return (after taxes on distributions); and (C) average annual total return (after taxes on distributions and redemption). A Money Market Fund should show only the returns described in clause (A) of the preceding sentence. All returns should be shown for 1-, 5-, and 10- calendar year periods ending on the date of the most recently completed calendar year (or for the life of the Fund, if shorter), but only for periods subsequent to the effective date of the Fund's registration statement. The table also shouldshow the returns of an appropriate broadbased securities market index as defined in Instruction 5 to Item 22(b)(7) for the same periods. A Fund that has been in existence for more than 10 years also may include returns for the life of the Fund. A Money Market Fund may provide the Fund's 7-day yield ending on the date of the most recent calendar year or disclose a toll-free (or collect) telephone number that investors can use to obtain the Fund's current 7-day yield. For a Fund (other than a Money Market Fund or a Fund described in General Instruction C.3.(d)(iii)), provide the information in the following table with the specified captions AVERAGE ANNUAL TOTAL RETURNS (For the periods ended December 31, _____). For a Fund that provides annual total returns for only one calendar year or for a Fund that does not include the bar chart because it does not have annual returns for a full calendar year, modify, as appropriate, the narrative explanation required by paragraph (c)(2)(i) (e.g., by stating that the information gives some indication of the risks of an investment in the Fund by comparing the Fund's performance with a broad measure of market performance).Reference 1: 1 -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 4 -Paragraph 2 -Subparagraph iv -Subsection b falsefalsePerformance Table Narrative132Risk/Return Summary (Janus Venture Fund)UnKnownUnKnownUnKnownUnKnownfalsetrue