XML 102 R51.htm IDEA: XBRL DOCUMENT v2.4.0.6
Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName JANUS INVESTMENT FUND
Prospectus Date rr_ProspectusDate Oct. 26, 2012
Janus World Allocation Fund | Class A, C, S, I, T Shares
  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Fund summary

Janus World Allocation Fund
Objective [Heading] rr_ObjectiveHeading INVESTMENT OBJECTIVE
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Janus World Allocation Fund seeks long-term growth of capital with a secondary emphasis on income.
Expense [Heading] rr_ExpenseHeading FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock This 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.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption SHAREHOLDER FEES
(fees paid directly from your investment)
Operating Expenses Caption [Text] rr_OperatingExpensesCaption ANNUAL FUND OPERATING EXPENSES
(expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination November 1, 2013
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover:
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” 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’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 36% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 36.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts For 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 “Purchases” section on page 31 of the Fund’s Prospectus and in the “Purchases” section on page 64 of the Fund’s Statement of Additional Information.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading EXAMPLE:
Expense Example by Year [Heading] rr_ExpenseExampleByYearHeading The 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’s operating expenses (including the operating expenses of the underlying funds) without waivers remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The 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.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption If Shares are redeemed:
Expense Example, No Redemption, By Year, Caption [Text] rr_ExpenseExampleNoRedemptionByYearCaption If Shares are not redeemed:
Strategy [Heading] rr_StrategyHeading PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The Fund pursues its investment objective by investing in a diversified portfolio of other Janus mutual funds (“underlying funds”) and securities that provide exposure to issuers located throughout the world. Through its investment in the underlying funds, the Fund invests in issuers from several different countries, including the United States, and may, under unusual circumstances, be invested in a single country. The Fund may also have significant exposure to emerging markets. Because it invests in other funds, the Fund is considered a “fund of funds.” The Fund utilizes Janus Capital’s proprietary process to allocate assets across the following three asset categories (as defined by Janus Capital):
  •   Core – The Core category seeks to provide market-like exposure by investing in funds that in turn primarily invest in a broad range of traditional asset classes such as large-, mid-, and small-cap stocks, U.S. and non-U.S. stocks, growth and value stocks, and investment-grade bonds. While not a primary strategy, the underlying funds may also invest in emerging market stocks and high-yield bonds. A primary goal of the underlying funds in the Core category is to provide shareholders with access to a broad range of investable assets in proportion to each asset class’ representation in today’s global, integrated market as determined by Janus Capital.
  •   Alpha – The Alpha category seeks to generate higher-than-market returns on a risk-adjusted basis by investing in funds that in turn invest in a broad range of traditional asset classes such as large-, mid-, and small-cap stocks, U.S. and non-U.S. stocks, growth and value stocks, emerging market stocks, investment-grade bonds, and high-yield bonds. Unlike funds in the Core category, the Alpha category is less focused on the asset class composition of the global market. Instead, the Alpha category is comprised of funds, unconstrained by asset class or investment style, that Janus Capital believes may generate higher-than-market returns over a market cycle.
  •   Alternative – The Alternative category is comprised of non-traditional investments with historically low correlation to the assets in the Core and Alpha categories, such as certain exchange-traded funds (“ETFs”), exchange-traded notes (“ETNs”), investments with hedge fund strategy exposure, commodities-related securities, real estate-related securities, and structured products.
The Fund attempts to maximize returns by investing the Fund’s assets in underlying funds investing in stocks (U.S. and non-U.S.), bonds, cash equivalents, alternative asset classes (such as real estate-related securities and commodity-related securities), and alternative investment strategies (such as leveraged and sector-based strategies). The target allocation of the Fund’s assets among underlying funds is based on an optimization process that utilizes quantitative analysis of a number of factors, such as historical risk, performance, fund classifications, and the relationship among underlying funds, as well as the portfolio manager’s judgment. Janus Capital analyzes Fund allocations on a regular basis in order to integrate current market data and reallocates on a quarterly basis.

The Fund’s portfolio manager determines the overall composition of the Fund, oversees the investment process, and is responsible for the day-to-day management of the Fund. The portfolio manager consults with a committee comprised of Janus Capital investment professionals (“Asset Allocation Committee”) to regularly review the process and the allocation of the Fund’s assets among the underlying funds to determine modifications to the underlying funds’ asset categories and/or weightings, or to substitute other underlying funds to emphasize and mitigate risk exposures that may arise as a result of the implementation of the allocations. The portfolio manager and Asset Allocation Committee normally review asset allocations on a quarterly basis. The portfolio manager oversees the implementation of trades on behalf of the Fund.

The Fund’s investments will be rebalanced to the identified optimal weightings on a quarterly basis, although more frequent changes can occur. The Fund’s asset class or category, category allocations, underlying funds, or underlying fund weightings may change without prior shareholder notice.

The Fund will normally allocate approximately 90% of its assets to Janus-managed mutual funds and approximately 10% to unaffiliated pooled investment vehicles (e.g., ETFs) and derivatives. For information on the potential underlying Janus funds currently available for investment by the Fund, including investment objectives and strategies, see “Investment Objectives and Strategies of the Underlying Funds” in Appendix A.

The Fund may invest in ETFs and ETNs to complement its investment in the underlying funds if there are asset classes not covered by the underlying funds or to better manage cash positions.

The Fund may invest its assets in derivatives, which are instruments that have a value derived from or directly linked to an underlying asset, such as equity securities, bonds, commodities, currencies, interest rates, or market indices, as substitutes for securities in which the Fund invests. The Fund may invest in derivative instruments (by taking long and/or short positions) including, but not limited to, swap agreements to earn income and enhance uncorrelated returns, to increase or decrease exposure to a particular market, to manage or adjust the risk profile of the Fund, or as alternatives to direct investments. For more information on the Fund’s use of derivatives, refer to the Fund’s shareholder reports and Form N-Q reports, which are filed with the Securities and Exchange Commission.

When market conditions dictate a more defensive strategy, the Fund or an underlying fund may temporarily hold cash or invest its assets in temporary investments. In that case, the Fund may take positions that are inconsistent with its investment objective. As a result, the Fund may not achieve its investment objective.
Risk [Heading] rr_RiskHeading PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock The biggest risk is that the Fund’s returns will vary, and you could lose money. The Fund is designed for long-term investors seeking growth of capital and, to a lesser extent, income. Investments in a portfolio with common stock and alternative investment exposure tend to be more volatile than many other investment choices.

Main Risks Associated with the Fund
Allocation Risk. The Fund’s ability to achieve its investment objective depends largely upon the portfolio manager’s allocation of assets among the underlying funds and other securities, using the optimization process and the judgment of the portfolio manager. You could lose money on your investment in the Fund as a result of these allocations. The Fund will typically invest in a number of different underlying funds; however, to the extent that the Fund invests a significant portion of its assets in a single underlying fund, it will be more sensitive to the risks associated with that fund and any investments in which that fund concentrates.

Derivatives Risk. The Fund and certain underlying funds may invest in derivatives. Derivatives can be highly volatile and involve risks in addition to the risks of the underlying referenced securities. Gains or losses from a derivative can be substantially greater than the derivative’s original cost, and can therefore involve leverage. Derivatives can be less liquid than other types of investments and entail the risk that the counterparty will default on its payment obligations.

Commodity-Linked Derivative Investment Risk. The Fund may invest in derivatives that have exposure to the commodities markets. This exposure may subject the Fund to greater volatility than investments in traditional securities. The value of a commodity-linked derivative investment typically is based upon the price movements of a physical commodity (such as heating oil, livestock, or agricultural products), a commodity futures contract or commodity index, or some other readily measurable economic variable. The value of commodity-linked derivative instruments may therefore be affected by changes in overall market movements, volatility of the underlying benchmark, changes in interest rates, or other factors affecting a particular industry or commodity such as drought, floods, weather, livestock disease, embargoes, tariffs, and international economic, political, and regulatory developments.

Exchange-Traded Funds Risk. The Fund may purchase shares of ETFs to gain exposure to a particular portion of the market. ETFs are pooled investment vehicles, which may be managed or unmanaged, that generally seek to track the performance of a specific index. ETFs are traded on an exchange at market prices that may vary from the net asset value of their underlying investments. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF’s expenses. ETFs have certain inherent risks generally associated with investments in a portfolio of securities in which the ETF is invested, including the risk that the general level of stock prices may decline, thereby adversely affecting the value of each unit of the ETF. ETFs also involve the risk that an active trading market for an ETF’s shares may not develop or be maintained.

Affiliated Fund Risk. Janus Capital has the authority to select and substitute underlying affiliated mutual funds. The fees paid to Janus Capital by some Janus mutual funds are generally higher than the fees paid to Janus Capital by the Fund or by other funds and share classes available for investment by the Fund. These conditions may create a conflict of interest when selecting underlying affiliated mutual funds and share classes for investment. Janus Capital, however, is a fiduciary to the Fund and its shareholders and is legally obligated to act in their best interest when selecting underlying affiliated mutual funds.

Main Risks Associated with the Underlying Funds and Securities
The biggest risk is that the underlying funds’ returns will vary, and you could lose money.

Market Risk. Underlying funds investing in equity securities are subject to the risks associated with investments in common stocks, which tend to be more volatile than many other investment choices. The value of an underlying fund’s portfolio may decrease if the value of an individual company or security, or multiple companies or securities, in the portfolio decreases or if a portfolio manager’s belief about a company’s intrinsic worth is incorrect. Further, regardless of how well individual companies or securities perform, the value of an underlying fund’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.

Fixed-Income Securities Risk. Through the Fund’s investments in underlying funds holding fixed-income securities, the Fund is subject to the risks associated with investments in a variety of fixed-income securities, which may be less volatile than underlying funds that invest most of their assets in common stocks; returns and yields will vary, and you could lose money. Typically, the values of fixed-income securities change inversely with prevailing interest rates. Therefore, a fundamental risk of fixed-income securities is interest rate risk, which is the risk that their value will generally decline as prevailing interest rates rise, which may cause an underlying fund’s net asset value to likewise decrease. How specific fixed-income securities may react to changes in interest rates will depend on the specific characteristics of each security. Fixed-income securities are also subject to credit risk, prepayment risk, valuation risk, and liquidity risk. Credit risk is the risk that the credit strength of an issuer of a fixed-income security will weaken and/or that the issuer will be unable to make timely principal and interest payments and that the security may go into default. Prepayment risk is the risk that during periods of falling interest rates, certain fixed-income securities with higher interest rates, such as mortgage- and asset-backed securities, may be prepaid by their issuers thereby reducing the amount of interest payments. Valuation risk is the risk that one or more of the fixed-income securities in which an underlying fund invests are priced incorrectly due to factors such as incomplete data, market instability, or human error. Liquidity risk is the risk that fixed-income securities may be difficult or impossible to sell at the time that an underlying fund’s portfolio manager would like or at the price that the portfolio manager believes the security is currently worth.

Foreign Exposure Risk. The Fund and certain underlying funds may have significant exposure to foreign markets as a result of their investments in foreign securities, including investments in emerging markets, which can be more volatile than the U.S. markets. As a result, the Fund’s and an underlying fund’s 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 or an underlying fund has invested a significant amount of its assets may have a greater effect on the Fund’s or an underlying Fund’s performance than it would in a more geographically diversified portfolio. The Fund’s or an underlying fund’s investments in emerging market countries may involve risks greater than, or in addition to, the risks of investing in more developed countries.

Emerging Markets Risk. The risks of foreign investing mentioned above are heightened when investing in emerging markets. Emerging markets securities involve a number of additional risks, which may result from less government supervision and regulation of business and industry practices (including the potential lack of strict finance and accounting controls and standards), stock exchanges, brokers, and listed companies, making these investments potentially more volatile in price and less liquid than investments in developed securities markets, resulting in greater risk to investors. In addition, the Fund’s or an underlying fund’s investments may be denominated in foreign currencies and therefore, changes in the value of a country’s currency compared to the U.S. dollar may affect the value of the Fund’s or an underlying fund’s investments. To the extent that the Fund or an underlying fund invests a significant portion of its assets in the securities of issuers in or companies of a single country or region, it is more likely to be impacted by events or conditions affecting that country or region, which could have a negative impact on the Fund’s performance. Some of the risks of investing directly in foreign and emerging market securities may be reduced when the Fund or an underlying fund invests indirectly in foreign securities through various other investment vehicles including derivatives, which also involve other risks.

Mortgage-Backed Securities Risk. Mortgage-backed securities tend to be more sensitive to changes in interest rates than other types of securities. Investments in mortgage-backed securities are subject to both extension risk, where borrowers extend the duration of their mortgages in times of rising interest rates, and prepayment risk, where borrowers pay off their mortgages sooner than expected in times of declining interest rates. These risks may reduce the Fund’s returns. In addition, investments in mortgage-backed securities, including those comprised of subprime mortgages, may be subject to a higher degree of credit risk, valuation risk, and liquidity risk than various other types of fixed-income securities.

Sovereign Debt Risk. An underlying fund may invest in U.S. and foreign government debt securities (“sovereign debt”). Investments in U.S. sovereign debt are considered low risk. However investments in non-U.S. sovereign debt can involve a high degree of risk, including the risk that the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or to pay the interest on its sovereign debt in a timely manner.

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.
Risk Lose Money [Text] rr_RiskLoseMoney The biggest risk is that the Fund’s returns will vary, and you could lose money.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution 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.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading PERFORMANCE INFORMATION
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The following information provides some indication of the risks of investing in the Fund by showing how the Fund’s performance has varied over time. Class I Shares, Class A Shares, Class C Shares, and Class S Shares of the Fund commenced operations on July 6, 2009, after the reorganization of each corresponding class of shares of Janus Adviser Modular Portfolio Construction® Fund (“JAD predecessor fund”) into each respective share class of the Fund. Class T Shares of the Fund commenced operations on July 6, 2009.
  • The performance shown for Class I Shares, Class A Shares, Class C Shares, and Class S Shares for periods prior to July 6, 2009, reflects the historical performance of the JAD predecessor fund’s Class I Shares, Class A Shares, Class C Shares and Class S Shares prior to the reorganization, calculated using the fees and expenses of each respective share class of the JAD predecessor fund, net of any applicable fee and expense limitations or waivers.
  • The performance shown for Class T Shares for periods prior to July 6, 2009, reflects the historical performance of the JAD predecessor fund’s Class I Shares prior to the reorganization, calculated using the fees and expenses of Class T Shares, without the effect of any fee and expense limitations or waivers.
If Class T Shares of the Fund had been available during periods prior to July 6, 2009, the performance shown may have been different. The performance shown for periods following the Fund’s commencement of Class I Shares, Class A Shares, Class C Shares, Class S Shares, and Class T Shares reflects the fees and expenses of each respective share class, net of any applicable fee and expense limitations or waivers.

The bar chart depicts the change in performance from year to year during the periods indicated. Performance information for each underlying fund is available in its prospectus and/or the most recent annual or semiannual report. 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’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. For certain periods, the Fund’s performance reflects the effect of expense waivers. Without the effect of these expense waivers, the performance shown would have been lower.

The Fund’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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The following information provides some indication of the risks of investing in the Fund by showing how the Fund’s performance has varied over time.

The bar chart depicts the change in performance from year to year during the periods indicated.
Performance Additional Market Index [Text] rr_PerformanceAdditionalMarketIndex The table compares the Fund’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.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-877-335-2687
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress janus.com/advisor/mutual-funds
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Annual Total Returns for Class I Shares (calendar year-end)
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
Best Quarter:  Second Quarter 2009  14.90%          Worst Quarter:  Third Quarter 2011  −13.38%
Year to Date Return, Label rr_YearToDateReturnLabel The Fund’s year-to-date return as of the calendar quarter ended September 30, 2012 was 8.19%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns (periods ended 12/31/11)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate 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.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred 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.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown 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.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher If 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.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock The World Allocation Index is an internally-calculated, hypothetical combination of unmanaged indices that combines total returns from the MSCI All Country World Indexsm (65%) and the Barclays Global Aggregate Bond Index (35%).

After-tax returns are calculated using distributions for the Fund’s Class I Shares for periods following July 6, 2009; and for the JAD predecessor fund’s Class I Shares for periods prior to July 6, 2009. 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.

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.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock Updated performance information is available at janus.com/advisor/mutual-funds or by calling 1-877-335-2687.
Janus World Allocation Fund | Class A, C, S, I, T Shares | Class A
  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees Column [Text] rr_ShareholderFeesColumnName
Class A
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds) rr_MaximumDeferredSalesChargeOverOther none
Operating Expenses Column [Text] rr_OperatingExpensesColumnName
Class A
Management Fees rr_ManagementFeesOverAssets 0.07%
Distribution/Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 1.73%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.74%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.79% [1]
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets 1.33% [1]
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 1.46% [1]
Expense Example, By Year, Column [Text] rr_ExpenseExampleByYearColumnName
Class A Shares
1 Year rr_ExpenseExampleYear01 841
3 Years rr_ExpenseExampleYear03 1,390
5 Years rr_ExpenseExampleYear05 1,964
10 Years rr_ExpenseExampleYear10 3,514
Expense Example, No Redemption, By Year, Column [Text] rr_ExpenseExampleNoRedemptionByYearColumnName
Class A Shares
1 Year rr_ExpenseExampleNoRedemptionYear01 841
3 Years rr_ExpenseExampleNoRedemptionYear03 1,390
5 Years rr_ExpenseExampleNoRedemptionYear05 1,964
10 Years rr_ExpenseExampleNoRedemptionYear10 3,514
Janus World Allocation Fund | Class A, C, S, I, T Shares | Class C
  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees Column [Text] rr_ShareholderFeesColumnName
Class C
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds) rr_MaximumDeferredSalesChargeOverOther 1.00%
Operating Expenses Column [Text] rr_OperatingExpensesColumnName
Class C
Management Fees rr_ManagementFeesOverAssets 0.07%
Distribution/Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses rr_OtherExpensesOverAssets 1.84%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.74%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 3.65% [1]
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets 1.44% [1]
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 2.21% [1]
Expense Example, By Year, Column [Text] rr_ExpenseExampleByYearColumnName
Class C Shares
1 Year rr_ExpenseExampleYear01 467
3 Years rr_ExpenseExampleYear03 1,117
5 Years rr_ExpenseExampleYear05 1,888
10 Years rr_ExpenseExampleYear10 3,906
Expense Example, No Redemption, By Year, Column [Text] rr_ExpenseExampleNoRedemptionByYearColumnName
Class C Shares
1 Year rr_ExpenseExampleNoRedemptionYear01 367
3 Years rr_ExpenseExampleNoRedemptionYear03 1,117
5 Years rr_ExpenseExampleNoRedemptionYear05 1,888
10 Years rr_ExpenseExampleNoRedemptionYear10 3,906
Janus World Allocation Fund | Class A, C, S, I, T Shares | Class S
  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees Column [Text] rr_ShareholderFeesColumnName
Class S
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds) rr_MaximumDeferredSalesChargeOverOther none
Operating Expenses Column [Text] rr_OperatingExpensesColumnName
Class S
Management Fees rr_ManagementFeesOverAssets 0.07%
Distribution/Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses rr_OtherExpensesOverAssets 1.96%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.74%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 3.02% [1]
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets 1.31% [1]
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 1.71% [1]
Expense Example, By Year, Column [Text] rr_ExpenseExampleByYearColumnName
Class S Shares
1 Year rr_ExpenseExampleYear01 305
3 Years rr_ExpenseExampleYear03 933
5 Years rr_ExpenseExampleYear05 1,587
10 Years rr_ExpenseExampleYear10 3,337
Expense Example, No Redemption, By Year, Column [Text] rr_ExpenseExampleNoRedemptionByYearColumnName
Class S Shares
1 Year rr_ExpenseExampleNoRedemptionYear01 305
3 Years rr_ExpenseExampleNoRedemptionYear03 933
5 Years rr_ExpenseExampleNoRedemptionYear05 1,587
10 Years rr_ExpenseExampleNoRedemptionYear10 3,337
Janus World Allocation Fund | Class A, C, S, I, T Shares | Class I
  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees Column [Text] rr_ShareholderFeesColumnName
Class I
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds) rr_MaximumDeferredSalesChargeOverOther none
Operating Expenses Column [Text] rr_OperatingExpensesColumnName
Class I
Management Fees rr_ManagementFeesOverAssets 0.07%
Distribution/Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 1.76%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.74%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.57% [1]
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets 1.36% [1]
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 1.21% [1]
Expense Example, By Year, Column [Text] rr_ExpenseExampleByYearColumnName
Class I Shares
1 Year rr_ExpenseExampleYear01 260
3 Years rr_ExpenseExampleYear03 799
5 Years rr_ExpenseExampleYear05 1,365
10 Years rr_ExpenseExampleYear10 2,905
Expense Example, No Redemption, By Year, Column [Text] rr_ExpenseExampleNoRedemptionByYearColumnName
Class I Shares
1 Year rr_ExpenseExampleNoRedemptionYear01 260
3 Years rr_ExpenseExampleNoRedemptionYear03 799
5 Years rr_ExpenseExampleNoRedemptionYear05 1,365
10 Years rr_ExpenseExampleNoRedemptionYear10 2,905
2009 rr_AnnualReturn2009 28.87%
2010 rr_AnnualReturn2010 11.54%
2011 rr_AnnualReturn2011 (8.00%)
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2012
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 8.19%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Best Quarter:
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 14.90%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Worst Quarter:
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2011
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (13.38%)
Janus World Allocation Fund | Class A, C, S, I, T Shares | Class T
  
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees Column [Text] rr_ShareholderFeesColumnName
Class T
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds) rr_MaximumDeferredSalesChargeOverOther none
Operating Expenses Column [Text] rr_OperatingExpensesColumnName
Class T
Management Fees rr_ManagementFeesOverAssets 0.07%
Distribution/Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 1.89%
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.74%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.70% [1]
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets 1.24% [1]
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 1.46% [1]
Expense Example, By Year, Column [Text] rr_ExpenseExampleByYearColumnName
Class T Shares
1 Year rr_ExpenseExampleYear01 273
3 Years rr_ExpenseExampleYear03 838
5 Years rr_ExpenseExampleYear05 1,430
10 Years rr_ExpenseExampleYear10 3,032
Expense Example, No Redemption, By Year, Column [Text] rr_ExpenseExampleNoRedemptionByYearColumnName
Class T Shares
1 Year rr_ExpenseExampleNoRedemptionYear01 273
3 Years rr_ExpenseExampleNoRedemptionYear03 838
5 Years rr_ExpenseExampleNoRedemptionYear05 1,430
10 Years rr_ExpenseExampleNoRedemptionYear10 3,032
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return Before Taxes | Class A
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class A Shares
Label rr_AverageAnnualReturnLabel
Return Before Taxes
 [2]
1 Year rr_AverageAnnualReturnYear01 (13.24%)
Since Inception rr_AverageAnnualReturnSinceInception (1.79%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return Before Taxes | Class C
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class C Shares
Label rr_AverageAnnualReturnLabel
Return Before Taxes
 [3]
1 Year rr_AverageAnnualReturnYear01 (9.46%)
Since Inception rr_AverageAnnualReturnSinceInception (0.62%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return Before Taxes | Class S
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class S Shares
Label rr_AverageAnnualReturnLabel
Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (8.07%)
Since Inception rr_AverageAnnualReturnSinceInception (0.19%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return Before Taxes | Class I
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class I Shares
Label rr_AverageAnnualReturnLabel
Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (8.00%)
Since Inception rr_AverageAnnualReturnSinceInception 0.06%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return Before Taxes | Class T
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class T Shares
Label rr_AverageAnnualReturnLabel
Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (7.87%)
Since Inception rr_AverageAnnualReturnSinceInception 0.03%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return After Taxes on Distributions | Class I
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class I Shares
Label rr_AverageAnnualReturnLabel
Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (9.03%)
Since Inception rr_AverageAnnualReturnSinceInception (0.71%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Return After Taxes on Distributions and Sale of Fund Shares | Class I
  
Risk/Return: rr_RiskReturnAbstract  
Column rr_AverageAnnualReturnColumnName
Class I Shares
Label rr_AverageAnnualReturnLabel
Return After Taxes on Distributions and Sale of Fund Shares
 [4]
1 Year rr_AverageAnnualReturnYear01 (4.11%)
Since Inception rr_AverageAnnualReturnSinceInception (0.15%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | Morgan Stanley Capital International All Country World Index (net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)
  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel Morgan Stanley Capital International All Country World Indexsm (net of foreign withholding taxes)
1 Year rr_AverageAnnualReturnYear01 (7.35%)
Since Inception rr_AverageAnnualReturnSinceInception (0.71%)
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
Janus World Allocation Fund | Class A, C, S, I, T Shares | World Allocation Index (reflects no deduction for expenses, fees, or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
Label rr_AverageAnnualReturnLabel World Allocation Index
1 Year rr_AverageAnnualReturnYear01 (2.72%)
Since Inception rr_AverageAnnualReturnSinceInception 2.25%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 03, 2008
[1] Janus Capital has contractually agreed to waive the Fund's total annual fund operating expenses (excluding any expenses of an underlying fund (acquired fund fees and expenses), 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 (except for networking and omnibus fees for Class A Shares, Class C Shares, and Class I Shares); brokerage commissions; interest; dividends; taxes; and extraordinary expenses) to 0.45% until at least November 1, 2013. The contractual waiver may be terminated or modified prior to this date only at the discretion of the Board of Trustees.
[2] Calculated assuming maximum permitted sales loads.
[3] The one year return is calculated to include the contingent deferred sales charge.
[4] If 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.