Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	JANUS INVESTMENT FUND
Prospectus Date	rr_ProspectusDate	Oct. 27, 2023
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Times New Roman;font-size:15.20pt;font-weight:bold;margin-left:3pt;">Janus Henderson Global Allocation Fund – Conservative</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0pt;text-transform:uppercase;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Janus Henderson Global Allocation Fund – Conservative seeks total return through a primary emphasis on income with a secondary emphasis on growth of capital.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0pt;text-transform:uppercase;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy, hold, and sell Shares of the Fund. Each share class has different expenses, but represents an investment in the same Fund. 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 Henderson 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 60 of the Fund’s Prospectus and in the “Purchases” section on page 61 of the Fund’s Statement of Additional Information. In addition, please see Appendix B – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares of the Fund that are not reflected in the table or in the example below.
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	<span style="font-family:Times New Roman;font-size:7.60pt;">The Adviser has contractually agreed to waive its investment advisory fee and/or reimburse operating expenses to the extent that the Fund’s total annual fund operating expenses (excluding any expenses of an underlying fund (acquired fund fees and expenses), the fees payable pursuant to a Rule 12b-1 plan, shareholder servicing fees, such as transfer agency fees (including out-of-pocket costs), administrative services fees and any networking/omnibus fees payable by any share class; brokerage commissions; interest; dividends; taxes; and extraordinary expenses) exceed 0.14% for at least a one-year period commencing on October 27, 2023. This contractual waiver may be terminated or modified only at the discretion of the Board of Trustees.</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="font-family:Times New Roman;font-size:9.50pt;font-weight:bold;">Portfolio Turnover:</span>
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 41% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	41.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	<span style="font-family:Times New Roman;font-size:9.50pt;">For Class A Shares, you may qualify for sales charge </span><span style="font-family:Times New Roman;font-size:9.50pt;">discounts if you and your family invest, or agree to invest in the future, at least </span><span style="font-family:Times New Roman;font-size:9.50pt;">$50,000</span><span style="font-family:Times New Roman;font-size:9.50pt;"> in the Fund or in other Janus Henderson 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 60 of the Fund’s Prospectus and in the “Purchases” section on page 61 of the Fund’s Statement of Additional Information. In addition, please see Appendix B – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares of the Fund that are not reflected in the table or in the example below.</span>
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 50,000
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	<span style="font-family:Times New Roman;font-size:7.60pt;">“Acquired Fund” refers to any underlying fund (including, but not limited to, exchange-traded funds) in which the Fund invests or has invested during the period. Acquired fund fees and expenses are indirect expenses the Fund incurs as a result of investing in shares of an underlying fund. The Fund’s “Total Annual Fund Operating Expenses” may not correlate to the “Ratio of gross expenses to average net assets” presented in the Financial Highlights tables because that ratio includes only the direct operating expenses incurred by the Fund, not the indirect costs of investing in Acquired Funds.</span>
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-weight:bold;">EXAMPLE:</span>
Expense Example by Year [Heading]	rr_ExpenseExampleByYearHeading	<span style="font-family:Times New Roman;font-size:9.50pt;">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) are equal to the Total Annual Fund Operating Expenses After Fee Waiver for the first year and the Total Annual Fund Operating Expenses thereafter. Class C Shares automatically </span><span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">convert to Class A Shares after eight years. The Example for Class C Shares for the ten-year period reflects the conversion to Class A Shares. Although your actual costs may be higher or lower, based on these assumptions your costs would be:</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	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	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0pt;text-transform:uppercase;">Principal investment strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing in other Janus Henderson mutual funds and exchange-traded funds (“ETFs”) (“underlying funds”) that represent a variety of asset classes and investment styles and provide exposure to issuers that are economically tied to countries throughout the world. Through its investments in underlying funds, the Fund invests in issuers from several different countries. As a result, the Fund normally will have approximately 40% to 65% of its net assets allocated to non-U.S. investments. A security is deemed to be economically tied to a country or countries outside of the United States if one or more of the following tests are met: (i) the company is organized in, or its primary business office or principal trading market of its equity is located in, a country outside of the United States; (ii) a majority of the company’s revenues are derived from outside of the United States; or (iii) a majority of the company’s assets are located outside of the United States. The Fund may also have significant exposure to emerging markets.The Fund invests in a diversified portfolio of underlying funds, resulting in an allocation of the Fund’s investments that normally provides exposure to fixed-income securities, money market instruments, equity investments, and, if available, alternative investments. The underlying equity funds may invest across a wide range of market capitalizations and segments, including emerging markets, and employ various investment strategies and styles such as growth and value. The underlying fixed-income funds encompass a wide range of fixed-income sectors, including corporate bonds, government securities, mortgage- and asset-backed securities, bank loans, and commercial paper. The target allocation and the allocation of the Fund’s assets among underlying funds are based on quantitative and qualitative analysis. Because it invests in other funds, the Fund is considered a “fund of funds.”The Fund’s asset allocation is intended to diversify investments throughout the world among equity investments, fixed-income securities, cash equivalents, and, to the extent available, alternative investments. Portfolio management determines the overall composition of the Fund, oversees the investment process, and is responsible for the day-to-day management of the Fund. Portfolio management continually monitors asset class allocations and rebalances the Fund’s investments in the underlying funds as needed. Portfolio management also regularly reviews the allocation of Fund assets in the underlying funds and may modify the underlying funds’ weightings or substitute other underlying funds to emphasize and mitigate risk exposures that may arise as a result of the implementation of the allocations.The Fund will normally allocate 50%-65% of its investments to underlying funds that provide varying exposure to fixed-income and money market instruments with varying maturities and duration, credit exposure and regional exposure. The Fund will normally allocate 30%-50% of its investments to underlying funds that provide varying exposure to common stocks of U.S.-based companies and international companies of varying market capitalizations (including those with exposure to emerging markets), and to the extent alternative investment strategies are available, 0%-20% of its investments to underlying funds that seek returns uncorrelated with the returns of stocks and bonds by providing exposure to alternative investments and alternative investment strategies.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 policies. As a result, the Fund may not achieve its investment objective.Refer to Appendix A of the Prospectus for a brief description of the investment strategies of each of the currently available underlying funds.
Risk [Heading]	rr_RiskHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0pt;text-transform:uppercase;">Principal investment risks</span>
Risk [Text Block]	rr_RiskTextBlock	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 income and, to a lesser extent, growth of capital. Investments in a portfolio with common stock and alternative investment exposure tend to be more volatile than many other investment choices. The principal risks associated with investing in the Fund and the underlying funds are set forth below.Main Fund-Level Risks
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0pt;text-transform:uppercase;">Performance information</span>
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 T Shares (formerly named Class J Shares, the initial share class) of the Fund commenced operations with the Fund’s inception. Class A Shares, Class C Shares, Class S Shares, and Class I Shares of the Fund commenced operations on July 6, 2009.•The performance shown for Class T Shares is calculated using the fees and expenses of Class T Shares in effect during the periods shown, net of any applicable fee and expense limitations or waivers.•The performance shown for Class A Shares, Class C Shares, Class S Shares, and Class I Shares for periods prior to July 6, 2009, reflects the performance of the Fund’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.If Class A Shares, Class C Shares, Class S Shares, and Class I Shares of the Fund had been available during periods prior to July 6, 2009, the performance shown for each respective share class may have been different. The performance shown for the periods following the Fund’s commencement of Class A Shares, Class C Shares, Class S Shares, and Class I 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 a broad-based securities market index, as well as to one or more supplemental indices that have investment characteristics similar to those of the Fund. 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 atjanushenderson.com/performance or by calling 1-877-335-2687.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">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.</span><span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">The table compares the Fund’s average annual returns for the periods indicated to a broad-based securities market index, as well as to one or more supplemental indices that have investment characteristics similar to those of the Fund. All figures assume reinvestment of dividends and distributions.</span>
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">The table compares the Fund’s average annual returns for the periods indicated to a broad-based securities market index, as well as to one or more supplemental indices that have investment characteristics similar to those of the Fund. All figures assume reinvestment of dividends and distributions.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-style:italic;">1-877-335-2687</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-style:italic;">janushenderson.com/performance</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-style:italic;">The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for Class T 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:2nd Quarter 20209.71%Worst Quarter:2nd Quarter 2022– 11.41%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Times New Roman;font-size:9.50pt;margin-left:3pt;">The Fund’s year-to-date return as of the calendar quarter ended </span><span style="font-family:Times New Roman;font-size:9.50pt;">September 30, 2023 was 0.58%.</span>
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (periods ended 12/31/22)
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	<span style="color:#000000;font-family:Times New Roman;font-size:7.60pt;">The one year return is calculated to include the contingent deferred sales charge.</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">After-tax returns are calculated using the historically highest individual federal marginal income tax rates and do </span><span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">not reflect the impact of state and local taxes. </span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">Actual after-tax returns depend on your individual tax situation and may differ </span><span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">from those shown in the preceding table. The after-tax return information shown above does not apply to Fund shares held through a tax-advantaged account, such as a 401(k) plan or an IRA.</span>
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;">After-tax returns are only shown for Class T Shares of the Fund. After-tax returns for the other classes of Shares will vary from those shown for Class T Shares due to varying sales charges (as applicable), fees, and expenses among the classes.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Times New Roman;font-size:7.60pt;">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.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s primary benchmark index is the Bloomberg Global Aggregate Bond Index. The Fund also compares its performance to the Global Conservative Allocation Index. The indices are described below.•The Bloomberg Global Aggregate Bond Index is a broad-based measure of the global investment grade fixed-rate debt markets.•The Global Conservative Allocation Index is an internally-calculated, hypothetical combination of unmanaged indices that combines total returns from the Bloomberg Global Aggregate Bond Index (60%) and the MSCI All Country World Indexsm(40%).After-tax returns are calculated using distributions for the Fund’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-advantaged account, such as a 401(k) plan or an IRA.After-tax returns are only shown for Class T Shares of the Fund. After-tax returns for the other classes of Shares will vary from those shown for Class T 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 atjanushenderson.com/performance or by calling 1-877-335-2687.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	The biggest risk is that the Fund’s returns will vary, and you could lose money.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	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.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Affiliated Underlying Fund Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Affiliated Underlying Fund Risk. The Adviser has the authority to select and substitute the underlying funds in which the Fund primarily invests. The fees paid to the Adviser by some underlying funds are generally higher than the fees paid by the Fund or other underlying funds, which may create a conflict of interest when selecting underlying funds and share classes for investment. The Adviser, however, is a fiduciary to the Fund and is legally obligated to act in its best interest when selecting underlying funds, without taking fees into consideration.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Underlying ETF Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Underlying ETF Risk. Underlying funds that are ETFs (“underlying ETFs”) are traded on a national securities exchange at market prices that may vary from the net asset value of their underlying investments. Accordingly, there may be times when an underlying ETF trades at a premium or discount to its net asset value. Underlying ETFs also involve the risk that an active trading market for an underlying ETF’s shares may not develop or be maintained. Similarly, because the value of underlying ETF shares depends on the demand in the market, the Fund may not be able to purchase or sell an underlying ETF at the most optimal time, which could adversely affect the Fund’s performance. Trading of an underlying ETF’s shares may be halted by the activation of individual or market-wide “circuit breakers” (which halt trading for a specific period of time when the price of a particular security or overall market prices decline by a specified percentage). Trading of an underlying ETF’s shares may also be halted if (i) the shares are delisted from an exchange without first being listed on another exchange or (ii) exchange officials determine that such action is appropriate in the interest of a fair and orderly market or for the protection of investors.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Allocation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Allocation Risk. The Fund’s ability to achieve its investment objective depends largely upon portfolio management’s allocation of assets among the underlying funds and other securities, using the optimization process (a process that utilizes quantitative analysis of a number of factors, such as historical risk, performance, fund classifications, and the relationship among underlying funds) and the judgment of portfolio management. 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 focuses.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Indirect Risks Through Investing in the Underlying Funds [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Indirect Risks Through Investing in the Underlying FundsThe ability of the Fund to realize its investment objective will depend, in large part, on the extent to which the underlying funds realize their respective investment objectives. Similarly, the Fund’s investment performance is directly related to the investment performance of the underlying funds it holds. The Fund is subject to the risk factors associated with the investments of the underlying funds, and will be affected by such risks in direct proportion to the allocation of its assets among the underlying funds. Therefore, to the extent that the Fund invests significantly in a particular underlying fund, the Fund’s performance would be significantly impacted by the performance of such underlying fund. What follows are the main risks associated with the underlying funds, which, in turn, may be considered to be principal risks of the Fund. These risks are subject to change based on the allocation of the Fund’s assets among the underlying funds.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Market Risk. The value of an underlying fund’s portfolio may decrease due to short-term market movements and over more prolonged market downturns. As a result, an underlying fund’s net asset value may fluctuate and it may be more difficult to value or sell an underlying fund’s holdings.Market risk may affect a single issuer, industry, economic sector, or the market as a whole. Market risk may be magnified if certain social, political, economic, and other conditions and events (such as terrorism, conflicts, including related sanctions, social unrest, natural disasters, epidemics and pandemics, including COVID-19) adversely interrupt the global economy and financial markets. 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.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Growth Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Growth Securities Risk. Securities of companies perceived to be “growth” companies may be more volatile than other stocks and may involve special risks. If portfolio management’s perception of a company’s growth potential is not realized, the securities purchased may not perform as expected, reducing the underlying fund’s returns. In addition, because different types of stocks tend to shift in and out of favor depending on market and economic conditions, “growth” stocks may perform differently from other types of securities and the market as a whole.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Emerging Markets Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Emerging Markets Risk. Emerging market securities involve a number of 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. Information about emerging market companies, including financial information, may be less available or reliable and the Adviser’s ability to conduct due diligence with respect to such companies may be limited. Accordingly, these investments may be potentially more volatile in price and less liquid than investments in developed securities markets, resulting in greater risk to investors. There is a risk in developing countries that a current or future economic or political crisis could lead to price controls, forced mergers of companies, expropriation or confiscatory taxation, imposition or enforcement of foreign ownership limits, seizure, nationalization, sanctions or imposition of restrictions by various governmental entities on investment and trading, or creation of government monopolies, any of which may have a detrimental effect on an underlying fund’s investments. In addition, the taxation systems at the federal, regional, and local levels in developing or emerging market countries may be less transparent, inconsistently enforced, and subject to change. Emerging markets may be subject to a higher degree of corruption and fraud than developed markets and financial institutions and transaction counterparties may have less financial sophistication, creditworthiness, and/or resources than participants in developed markets. In addition, 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 an underlying fund’s investments. To the extent that an underlying fund invests a significant portion of its assets in the securities of emerging markets 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.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Fixed-Income Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Fixed-Income Securities Risk. Fixed-income securities are generally subject to the following risks:•Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. Changing interest rates have unpredictable effects on the markets and may expose fixed-income and related markets to heightened volatility.•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 debt obligations may be paid off quicker than originally anticipated, which may cause an underlying fund to reinvest its assets in securities with lower yields, resulting in a decline in an underlying fund’s income or return potential.•Extension risk is the risk that, during periods of rising interest rates, certain debt obligations may be paid off substantially slower than originally anticipated, and as a result, the value of those obligations may fall.•Valuation risk is the risk that one or more of the fixed-income securities in which an underlying fund invests are priced differently than the value realized upon such security’s sale. In times of market instability, valuation may be more difficult. Valuation may also be affected by changes in the issuer’s financial strength, the market’s perception of such strength, or in the credit rating of the issuer or the security.•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 management would like or at the price the underlying fund’s portfolio management believes the security is currently worth. Consequently, an underlying fund may have to accept a lower price to sell a security, sell other securities to raise cash, or give up an investment opportunity, any of which could have a negative effect on an underlying fund’sperformance. In unusual market conditions, even normally liquid securities may be affected by a degree of liquidity risk (i.e., if the number and capacity of traditional market participants is reduced).
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Sovereign Debt Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Sovereign Debt Risk. Investments in U.S. and non-U.S. government debt securities (“sovereign debt”), especially the debt of certain emerging market countries, 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. A sovereign debtor’s willingness or ability to satisfy its debt obligation may be affected by various factors including, but not limited to, its cash flow situation, the extent of its foreign currency reserves, the availability of foreign exchange when a payment is due, and the relative size of its debt position in relation to its economy as a whole. In the event of default, there may be limited or no legal remedies for collecting sovereign debt and there may be no bankruptcy proceedings through which the underlying fund may collect all or part of the sovereign debt that a governmental entity has not repaid. In addition, to the extent an underlying fund invests in non-U.S. sovereign debt, it may be subject to currency risk.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Foreign Exposure Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Foreign Exposure Risk. Foreign markets, including emerging markets, can be more volatile than the U.S. market. As a result, an underlying fund’s returns and net asset value may be affected by fluctuations in currency exchange rates or political or economic conditions in a particular country. In some foreign markets, there may not be protection against failure by other parties to complete transactions. It may not be possible for an underlying fund to repatriate capital, dividends, interest, and other income from a particular country or governmental entity. In addition, a market swing in one or more countries or regions where an underlying fund has invested a significant amount of its assets may have a greater effect on an underlying fund’s performance than it would in a more geographically diversified portfolio. An underlying fund’s investments in emerging market countries, if any, may involve risks greater than, or in addition to, the risks of investing in more developed countries.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Mortgage- and Asset-Backed Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Mortgage- and Asset-Backed Securities Risk. Mortgage- and asset-backed securities represent interests in “pools” of commercial or residential mortgages or other assets, including consumer loans or receivables. The value of mortgage- and asset-backed securities will be influenced by factors affecting the real estate market and the assets underlying these securities. Investments in mortgage-and asset-backed securities may be subject to credit risk, valuation risk, liquidity risk, extension risk, and prepayment risk. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Portfolio Management Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Portfolio Management Risk. The underlying funds are actively managed investment portfolios and are therefore subject to the risk that the investment strategies and/or research process employed for the underlying funds may fail to produce the intended results. As a result, the Fund may underperform its benchmark index or other mutual funds with similar investment objectives.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Volatility Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Volatility Risk. There is no guarantee that Janus Henderson Adaptive Risk Managed U.S. Equity Fund’s, an underlying fund, strategy to minimize volatility will be successful. Securities in the underlying fund’s portfolio may be subject to price volatility, and the prices may not be any less volatile than the market as a whole, and could be more volatile. In addition, the underlying fund’s strategy to minimize volatility could limit the underlying fund’s gains in rising markets.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Value Investing Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Value Investing Risk. Because different types of stocks tend to shift in and out of favor depending on market and economic conditions, “value” stocks may perform differently than other types of stocks and from the market as a whole, and can continue to be undervalued by the market for long periods of time. It is also possible that a value stock will never appreciate to the extent expected.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Investment Process Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Investment Process Risk. Portfolio management of Janus Henderson Adaptive Global Allocation Fund, an underlying fund, uses certain proprietary models, including a proprietary options implied information model, to implement Janus Henderson Adaptive Global Allocation Fund’s investment strategy. These models may not be successful in identifying how the underlying fund’s allocations and underlying security exposures should be adjusted in order to reduce the risk of loss while participating in the upside growth of capital markets. As a result, there is a risk that the underlying fund may underperform its benchmark if these models do not correctly identify indicators of risk and reward between asset classes, sectors, and regions.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | REIT Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	REIT Risk. Real estate investment trusts (“REITs”) are subject to certain risks inherent in the direct ownership of real estate, including without limitation, a possible lack of mortgage funds and associated interest rate risks, overbuilding, property vacancies, increases in property taxes and operating expenses, changes in zoning laws, losses due to environmental damages and changes in neighborhood values and appeal to purchasers. In addition, a REIT could fail to qualify for tax-free pass-through of its income under the Internal Revenue Code of 1986, as amended, or fail to maintain its exemption from registration under the Investment Company Act of 1940, as amended, which could produce adverse economic consequences for the REIT and its investors, including an underlying fund. Dividends received by an underlying fund from a REIT generally will not constitute qualified dividend income.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Alternative Investments Allocation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Alternative Investments Allocation Risk. There is a risk that the returns provided by alternative investments may be subject to high volatility and that an underlying fund’s portfolio management’s beliefs about the expected returns, risk and correlation properties of one or more of an underlying fund’s investments may be incorrect. There is also a risk that an underlying fund’s investments will correlate with the performance of stocks and bonds to a greater degree than anticipated. All of these factors may negatively affect your investment in the Fund and you could lose money. Investment in the underlying funds also involves derivatives, counterparty, leverage, real estate-related, and commodity-linked investment risks.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Derivatives Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Derivatives Risk. Derivatives can be volatile and involve risks in addition to the risks of the underlying referenced securities or asset. Gains or losses from a derivative investment can be substantially greater than the derivative’s original cost, and can therefore involve leverage. Leverage may cause an underlying fund to be more volatile than if it had not used leverage.Derivatives entail the risk that the counterparty will default on its payment obligations.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Commodity-Linked Investments Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Commodity-Linked Investments Risk. Certain underlying funds may invest in derivatives that have exposure to the commodities markets. Such exposure may subject an underlying fund to greater volatility than investments in traditional securities. The value of a given commodity-linked investment typically is based upon the price movements of a physical commodity (such as heating oil, livestock, agricultural products, or precious metals), a commodity futures contract or commodity index, or some other readily measurable economic variable. The value of commodity-linked instruments may therefore be affected by changes in overall market movements, volatility of a commodity index, 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.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Counterparty Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Counterparty Risk. Certain derivative and “over-the-counter” instruments, such as swaps and forwards, are subject to the risk that the other party to a contract will not fulfill its contractual obligations.
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Class A
Risk Return Abstract	rr_RiskReturnAbstract
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
Management Fees	rr_ManagementFeesOverAssets	0.05%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.21%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.15%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	0.03%	[2]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	1.12%	[2]
1 Year	rr_ExpenseExampleYear01	$ 683
3 Years	rr_ExpenseExampleYear03	917
5 Years	rr_ExpenseExampleYear05	1,169
10 Years	rr_ExpenseExampleYear10	1,890
1 Year	rr_ExpenseExampleNoRedemptionYear01	683
3 Years	rr_ExpenseExampleNoRedemptionYear03	917
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,169
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,890
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Class C
Risk Return Abstract	rr_RiskReturnAbstract
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%
Management Fees	rr_ManagementFeesOverAssets	0.05%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.22%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.91%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	0.03%	[2]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	1.88%	[2]
1 Year	rr_ExpenseExampleYear01	$ 291
3 Years	rr_ExpenseExampleYear03	597
5 Years	rr_ExpenseExampleYear05	1,029
10 Years	rr_ExpenseExampleYear10	2,033
1 Year	rr_ExpenseExampleNoRedemptionYear01	191
3 Years	rr_ExpenseExampleNoRedemptionYear03	597
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,029
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,033
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Class S
Risk Return Abstract	rr_RiskReturnAbstract
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
Management Fees	rr_ManagementFeesOverAssets	0.05%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.39%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.33%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	0.03%	[2]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	1.30%	[2]
1 Year	rr_ExpenseExampleYear01	$ 132
3 Years	rr_ExpenseExampleYear03	418
5 Years	rr_ExpenseExampleYear05	726
10 Years	rr_ExpenseExampleYear10	1,599
1 Year	rr_ExpenseExampleNoRedemptionYear01	132
3 Years	rr_ExpenseExampleNoRedemptionYear03	418
5 Years	rr_ExpenseExampleNoRedemptionYear05	726
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,599
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Class I
Risk Return Abstract	rr_RiskReturnAbstract
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
Management Fees	rr_ManagementFeesOverAssets	0.05%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.92%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	0.02%	[2]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.90%	[2]
1 Year	rr_ExpenseExampleYear01	$ 92
3 Years	rr_ExpenseExampleYear03	291
5 Years	rr_ExpenseExampleYear05	507
10 Years	rr_ExpenseExampleYear10	1,129
1 Year	rr_ExpenseExampleNoRedemptionYear01	92
3 Years	rr_ExpenseExampleNoRedemptionYear03	291
5 Years	rr_ExpenseExampleNoRedemptionYear05	507
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,129
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Class T
Risk Return Abstract	rr_RiskReturnAbstract
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
Management Fees	rr_ManagementFeesOverAssets	0.05%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.37%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.06%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	0.03%	[2]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	1.03%	[2]
1 Year	rr_ExpenseExampleYear01	$ 105
3 Years	rr_ExpenseExampleYear03	334
5 Years	rr_ExpenseExampleYear05	582
10 Years	rr_ExpenseExampleYear10	1,291
1 Year	rr_ExpenseExampleNoRedemptionYear01	105
3 Years	rr_ExpenseExampleNoRedemptionYear03	334
5 Years	rr_ExpenseExampleNoRedemptionYear05	582
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,291
2013	rr_AnnualReturn2013	10.73%
2014	rr_AnnualReturn2014	4.12%
2015	rr_AnnualReturn2015	(2.25%)
2016	rr_AnnualReturn2016	2.33%
2017	rr_AnnualReturn2017	12.80%
2018	rr_AnnualReturn2018	(5.17%)
2019	rr_AnnualReturn2019	12.02%
2020	rr_AnnualReturn2020	14.06%
2021	rr_AnnualReturn2021	3.88%
2022	rr_AnnualReturn2022	(16.97%)
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2023
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.58%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	9.71%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2022
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(11.41%)
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return Before Taxes | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(21.88%)	[3]
5 Years	rr_AverageAnnualReturnYear05	(0.42%)	[3]
10 Years	rr_AverageAnnualReturnYear10	2.37%	[3]
Since Inception	rr_AverageAnnualReturnSinceInception	4.06%	[3]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005	[3]
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return Before Taxes | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(18.50%)	[4]
5 Years	rr_AverageAnnualReturnYear05	0.07%	[4]
10 Years	rr_AverageAnnualReturnYear10	2.33%	[4]
Since Inception	rr_AverageAnnualReturnSinceInception	3.72%	[4]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005	[4]
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return Before Taxes | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(17.33%)
5 Years	rr_AverageAnnualReturnYear05	0.58%
10 Years	rr_AverageAnnualReturnYear10	2.80%
Since Inception	rr_AverageAnnualReturnSinceInception	4.22%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return Before Taxes | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.90%)
5 Years	rr_AverageAnnualReturnYear05	1.02%
10 Years	rr_AverageAnnualReturnYear10	3.24%
Since Inception	rr_AverageAnnualReturnSinceInception	4.68%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return Before Taxes | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.97%)
5 Years	rr_AverageAnnualReturnYear05	0.89%
10 Years	rr_AverageAnnualReturnYear10	3.12%
Since Inception	rr_AverageAnnualReturnSinceInception	4.58%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return After Taxes on Distributions | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(17.39%)
5 Years	rr_AverageAnnualReturnYear05	(0.46%)
10 Years	rr_AverageAnnualReturnYear10	1.69%
Since Inception	rr_AverageAnnualReturnSinceInception	3.32%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Return After Taxes on Distributions and Sale of Fund Shares | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(9.72%)	[5]
5 Years	rr_AverageAnnualReturnYear05	0.57%	[5]
10 Years	rr_AverageAnnualReturnYear10	2.21%	[5]
Since Inception	rr_AverageAnnualReturnSinceInception	3.39%	[5]
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 30, 2005	[5]
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Bloomberg Global Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.25%)
5 Years	rr_AverageAnnualReturnYear05	(1.66%)
10 Years	rr_AverageAnnualReturnYear10	(0.44%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.23%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Bloomberg Global Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.25%)
5 Years	rr_AverageAnnualReturnYear05	(1.66%)
10 Years	rr_AverageAnnualReturnYear10	(0.44%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.23%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Bloomberg Global Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.25%)
5 Years	rr_AverageAnnualReturnYear05	(1.66%)
10 Years	rr_AverageAnnualReturnYear10	(0.44%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.23%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Bloomberg Global Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.25%)
5 Years	rr_AverageAnnualReturnYear05	(1.66%)
10 Years	rr_AverageAnnualReturnYear10	(0.44%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.23%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Bloomberg Global Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.25%)
5 Years	rr_AverageAnnualReturnYear05	(1.66%)
10 Years	rr_AverageAnnualReturnYear10	(0.44%)
Since Inception	rr_AverageAnnualReturnSinceInception	2.23%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Global Conservative Allocation Index (reflects no deduction for expenses, fees, or taxes, except any applicable foreign withholding taxes) | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.91%)
5 Years	rr_AverageAnnualReturnYear05	1.33%
10 Years	rr_AverageAnnualReturnYear10	3.05%
Since Inception	rr_AverageAnnualReturnSinceInception	4.05%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Global Conservative Allocation Index (reflects no deduction for expenses, fees, or taxes, except any applicable foreign withholding taxes) | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.91%)
5 Years	rr_AverageAnnualReturnYear05	1.33%
10 Years	rr_AverageAnnualReturnYear10	3.05%
Since Inception	rr_AverageAnnualReturnSinceInception	4.05%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Global Conservative Allocation Index (reflects no deduction for expenses, fees, or taxes, except any applicable foreign withholding taxes) | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.91%)
5 Years	rr_AverageAnnualReturnYear05	1.33%
10 Years	rr_AverageAnnualReturnYear10	3.05%
Since Inception	rr_AverageAnnualReturnSinceInception	4.05%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Global Conservative Allocation Index (reflects no deduction for expenses, fees, or taxes, except any applicable foreign withholding taxes) | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.91%)
5 Years	rr_AverageAnnualReturnYear05	1.33%
10 Years	rr_AverageAnnualReturnYear10	3.05%
Since Inception	rr_AverageAnnualReturnSinceInception	4.05%
Class A C S I T Shares | Janus Henderson Global Allocation Fund - Conservative | Global Conservative Allocation Index (reflects no deduction for expenses, fees, or taxes, except any applicable foreign withholding taxes) | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(16.91%)
5 Years	rr_AverageAnnualReturnYear05	1.33%
10 Years	rr_AverageAnnualReturnYear10	3.05%
Since Inception	rr_AverageAnnualReturnSinceInception	4.05%

[1] “Acquired Fund” refers to any underlying fund (including, but not limited to, exchange-traded funds) in which the Fund invests or has invested during the period. Acquired fund fees and expenses are indirect expenses the Fund incurs as a result of investing in shares of an underlying fund. The Fund’s “Total Annual Fund Operating Expenses” may not correlate to the “Ratio of gross expenses to average net assets” presented in the Financial Highlights tables because that ratio includes only the direct operating expenses incurred by the Fund, not the indirect costs of investing in Acquired Funds.

[2] The Adviser has contractually agreed to waive its investment advisory fee and/or reimburse operating expenses to the extent that the Fund’s total annual fund operating expenses (excluding any expenses of an underlying fund (acquired fund fees and expenses), the fees payable pursuant to a Rule 12b-1 plan, shareholder servicing fees, such as transfer agency fees (including out-of-pocket costs), administrative services fees and any networking/omnibus fees payable by any share class; brokerage commissions; interest; dividends; taxes; and extraordinary expenses) exceed 0.14% for at least a one-year period commencing on October 27, 2023. This contractual waiver may be terminated or modified only at the discretion of the Board of Trustees.

[3] Calculated assuming maximum permitted sales loads.

[4] The one year return is calculated to include the contingent deferred sales charge.

[5] 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.