Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	JANUS INVESTMENT FUND
Prospectus Date	rr_ProspectusDate	Jan. 28, 2022
Class A C S I N R T Shares | Janus Henderson Balanced Fund
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 Balanced Fund</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0%;text-transform:uppercase;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Janus Henderson Balanced Fund seeks long-term capital growth, consistent with preservation of capital and balanced by current income.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0%;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 and hold 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 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 97 of the Fund’s Prospectus and in the “Purchases” section on page 82 of the Fund’s Statement of Additional Information. In addition, please see Appendix A – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares or Class N 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)
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 60% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	60.00%
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 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 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 97 of the Fund’s Prospectus and in the “Purchases” section on page 82 of the Fund’s Statement of Additional Information. In addition, please see Appendix A – Intermediary Sales Charge Waivers and Discounts. You may also incur brokerage commissions charged by your broker or financial intermediary when buying Class I Shares or Class N 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
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-weight:bold;margin-left:3pt;">EXAMPLE:</span>
Expense Example by Year [Heading]	rr_ExpenseExampleByYearHeading	<span style="color:#000000;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 remain the same. Class C Shares automatically 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:0.0%;text-transform:uppercase;">Principal investment strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund pursues its investment objective by normally investing 35-65% of its assets in equity securities and the remaining assets in fixed-income securities and cash equivalents. The Fund normally invests at least 25% of its assets in fixed-income senior securities. As of September 30, 2021, approximately 63.70% of the Fund’s assets were held in equity securities, including common stocks and preferred stocks, and 36.30% of the Fund’s assets were held in fixed-income securities and cash equivalents.The Fund’s equity investments include, but are not limited to, common stocks, preferred stocks, and other securities with equity characteristics. The Fund’s fixed-income investments include, but are not limited to, government notes and bonds, corporate bonds, commercial and residential mortgage-backed securities, and asset-backed securities. The Fund may also invest in money market instruments and commercial loans (such as bank loans). The Fund may invest in fixed and floating rate obligations with varying durations.The Fund will limit its investments in high-yield/high-risk bonds (also known as “junk” bonds) to 35% of the fixed-income portion of its net assets. The Fund may enter into “to be announced” or “TBA” commitments when purchasing mortgage-backed securities or other securities. The Fund may also invest in securities that cannot be offered for public resale unless registered under the applicable securities laws or that have a contractual restriction that prohibits or limits their resale (these are know as “restricted securities”). The Fund may also invest in foreign securities, which may include investments in emerging market securities.The Fund may also 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, fixed-income securities, commodities, currencies, interest rates, or market indices. In particular, the Fund may use forward currency contracts to offset risks associated with an investment, currency exposure, or market conditions and may use interest rate swaps and futures, including Treasury bond futures, to manage interest rate risk, yield curve positioning, and country exposure. The Fund may also use index credit default swaps for hedging purposes (to offset risks associated with an investment exposure, or market conditions), to increase or decrease the Fund’s exposure to a particular market, to manage or adjust the risk profile of the Fund relative to its benchmark index, and to earn income, enhance returns, or preserve capital. The Fund’s exposure to derivatives will vary, and may include derivatives that have characteristics similar to the securities in which the Fund may directly invest. The Fund may invest in short sales of derivatives instruments.The portfolio managers share day-to-day responsibility for the Fund’s investments. In choosing investments for the Fund, the portfolio manager who focuses on the equity portion of the Fund applies a “bottom up” approach. In other words, the portfolio manager looks at companies one at a time to determine if a company is an attractive investment opportunity and if it is consistent with the Fund’s investment policies. Factors that the equity portfolio manager may consider in his fundamental analysis include a company’s revenue growth potential, returns on capital, and balance sheet flexibility. The equity portfolio manager may generally consider selling a security when, among other things, it reaches or exceeds its targeted value, the investment thesis for owning the position has changed, or to rebalance industry or sector weightings.The portfolio managers who focus on the fixed-income portion of the Fund use research-driven, “top-down” and “bottom-up” factors to identify and manage exposure to risks across sectors, industries, and individual investments. The fixed-income portfolio managers evaluate expected risk-adjusted returns on a portfolio and position level by analyzing fundamentals, valuations, and market technical indicators.The Fund may lend portfolio securities on a short-term or long-term basis, in an amount equal to up to one-third of its total assets of its fixed-income investments as determined at the time of the loan origination.
Risk [Heading]	rr_RiskHeading	<span style="color:#FFFFFF;font-family:Times New Roman;font-size:10.45pt;font-weight:bold;margin-left:0.0%;text-transform:uppercase;">Principal investment risks</span>
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 a balanced portfolio, including common stocks and bonds. Common stocks tend to be more volatile than many other investment choices. The principal risks associated with investing in the Fund are set forth below.Market Risk. The value of the 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 the portfolio managers’ belief about a company’s intrinsic worth is incorrect. Further, regardless of how well individual companies or securities perform, the value of the 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. 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, social unrest, natural disasters, epidemics and pandemics, including COVID-19) adversely interrupt the global economy and financial markets.Growth Securities Risk. The Fund invests in companies that the portfolio managers believe have growth potential. Securities of companies perceived to be “growth” companies may be more volatile than other stocks and may involve special risks. If the portfolio managers’ perception of a company’s growth potential is not realized, the securities purchased may not perform as expected, reducing the 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 the market as a whole and other types of securities.Dividend-Oriented Stocks Risk. Companies that have paid regular dividends to shareholders may decrease or eliminate dividend payments in the future. A decrease in dividend payments by an issuer may result in a decrease in the value of the security held by the Fund or the Fund receiving less income.Fixed-Income Securities Risk. The Fund holds debt and other fixed-income securities. A fundamental risk of fixed-income securities is interest rate risk, which is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Fund may be subject to a greater risk of rising interest rates due to the current period of historically low rates. How specific fixed-income securities may react to changes in interest rates will depend on the specific characteristics of each security. For example, while securities with longer maturities and durations tend to offer higher yields, they also tend to be more sensitive to changes in prevailing interest rates and are therefore more volatile than shorter-term securities and are subject to greater market fluctuations as a result of changes in interest rates. Fixed-income securities are also subject to credit risk, prepayment risk, extension 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 debt obligations may be paid off quicker than originally anticipated, which may cause the Fund to reinvest its assets in securities with lower yields, resulting in a decline in the 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 the value of those securities may fall, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments.•Valuation risk is the risk that one or more of the fixed-income securities in which the Fund invests are priced differently than the value realized upon such security’s sale. In times of market instability, valuation may be more difficult.•Liquidity risk is the risk that fixed-income securities may be difficult or impossible to sell at the time that the portfolio managers would like or at the price the portfolio managers believe the security is currently worth.High-Yield/High-Risk Bond Risk. High-yield/high-risk bonds are considered speculative and may be more sensitive than other types of bonds to economic changes, political changes, or adverse developments specific to the company that issued the bond, which may adversely affect their value.Portfolio Management Risk. The Fund is an actively managed investment portfolio and is therefore subject to the risk that the investment strategies employed for the Fund may fail to produce the intended results. The Fund may underperform its benchmark index or other mutual funds with similar investment objectives.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. Mortgage- and asset-backed securities may be more sensitive to changes in interest rates than other types of debt securities. Investments in mortgage-and asset-backed securities may be subject to both extension risk and prepayment risk. These risks may reduce the Fund’sreturns. In addition, investments in certain mortgage- and asset-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.Loan Risk. The Fund may invest in a variety of loans. Bank loans are obligations of companies or other entities sometimes entered into in connection with recapitalizations, acquisitions, and refinancings. The Fund’s investments in bank loans are generally acquired as a participation interest in, or assignment of, loans originated by a lender or other financial institution. These investments may include institutionally-traded floating and fixed-rate debt securities. The bank loans underlying these securities often involve borrowers with low credit ratings whose financial conditions are troubled or uncertain, including companies that are highly leveraged. Loans are subject to credit risk, interest rate risk, and liquidity risk.Sovereign Debt Risk. The Fund may invest in U.S. and non-U.S. government debt securities (“sovereign debt”). Some investments in sovereign debt, such as U.S. sovereign debt, are considered low risk. However, investments in 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 Fund may collect all or part of the sovereign debt that a governmental entity has not repaid. In addition, to the extent the Fund invests in non-U.S. sovereign debt, it may be subject to currency risk.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 cantherefore involve leverage. Leverage may cause the Fund to be more volatile than if it had not used leverage. Derivatives can be less liquid than other types of investments and entail the risk that the counterparty will default on its payment obligations. The Fund may use derivatives for hedging purposes. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains or cause losses if the market moves in a manner different from that anticipated by the portfolio managers or if the cost of the derivative outweighs the benefit of the hedge.Liquidity Risk. The Fund may invest in securities or instruments that do not trade actively or in large volumes, and may make investments that are less liquid than other investments. Also, the Fund may make investments that may become less liquid in response to market developments or adverse investor perceptions. Investments that are illiquid or that trade in lower volumes may be more difficult to value. When there is no willing buyer and investments cannot be readily sold at the desired time or price, the Fund may have to accept a lower price or may not be able to sell the security or instrument at all. Investments in foreign securities, particularly those of issuers located in emerging market countries, tend to have greater exposure to liquidity risk than domestic securities. 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). An inability to sell one or more portfolio positions can adversely affect the Fund’s value or prevent the Fund from being able to take advantage of other investment opportunities.Floating Rate Obligations Risk. The Fund may invest in floating rate obligations with interest rates that reset regularly, maintaining a fixed spread over a stated reference rate. The interest rates on floating rate obligations typically reset quarterly, although rates on some obligations may adjust at other intervals. Unexpected changes in the interest rates on floating rate obligations could result in lower income to the Fund. In addition, the secondary market on which floating rate obligations are traded may be less liquid than the market for investment grade securities or other types of income-producing securities, which may have an adverse impact on their market price. There is also a potential that there is no active market to trade floating rate obligations, that there may be restrictions on their transfer, or that the issuer may default. As a result, the Fund may be unable to sell floating rate obligations at the desired time or may be able to sell only at a price less than fair market value.Foreign Exposure Risk. The Fund may have exposure to foreign markets as a result of its investments in foreign securities, including investments in emerging markets, which can be more volatile than the U.S. markets. As a result, its 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 the 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 the Fund has invested a significant amount of its assets may have a greater effect on the Fund’s performance than it would in a more geographically diversified portfolio. To the extent the Fund invests in foreign debt securities, such investments are sensitive to changes in interest rates. Additionally, investments in securities of foreign governments involve the risk that a foreign government may not be willing or able to pay interest or repay principal when due. Some of the risks of investing directly in foreign securities may be reduced when the Fund invests indirectly in such securities through various other investment vehicles including derivatives, but such investments also involve other risks. The 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.TBA Commitments Risk. The Fund may enter into “to be announced” or “TBA” commitments. Although the particular TBA securities must meet industry-accepted “good delivery” standards, there can be no assurance that a security purchased on a forward commitment basis will ultimately be issued or delivered by the counterparty. If the counterparty to a transaction fails to deliver the securities, the Fund could suffer a loss. Because TBA commitments do not require the delivery of a specific security, the characteristics of a security delivered to the Fund may be less favorable than expected. There is a risk that the security that the Fund buys will lose value between the purchase and settlement dates. TBA purchase and sales commitments may significantly increase the Fund’s portfolio turnover rate and are not included in the portfolio turnover rate calculation.Short Sales Risk. Short sales are speculative transactions and involve special risks, including a greater reliance on the ability to accurately anticipate the future value of a security. The Fund will suffer a loss if it sells a security short and the value of the security rises rather than falls. The Fund’s losses are potentially unlimited in a short sale transaction. The use of short sales may also cause the Fund to have higher expenses than those of other funds. In addition, due to the investment process of long and short positions, the Fund may be subject to additional transaction costs that may lower the Fund’s returns. The Fund’s use of short sales may also have a leveraging effect on the Fund’s portfolio and may increase losses and the volatility of returns.Restricted Securities Risk. Securities that have limitations on their resale are referred to as “restricted securities.” Investments in restricted securities, including securities issued under Regulation S and Rule 144A, could have the effect of decreasing the Fund’s liquidity profile or preventing the Fund from disposing of them promptly at advantageous prices. Restricted securities may be less liquid than other investments because such securities may not always be readily sold in broad public markets and may have no active trading market. As a result, they may be difficult to value because market quotations may not be readily available.LIBOR Replacement Risk. The Fund may invest in certain debt securities, derivatives, or other financial instruments that utilize the London Inter-Bank Offered Rate (“LIBOR”) as a reference rate for various rate calculations. The U.K. Financial Conduct Authority has announced that it intends to stop compelling or inducing banks to submit rates for many LIBOR settings after December 31, 2021, and for certain other commonly-used U.S. dollar LIBOR settings after June 30, 2023. The elimination of LIBOR or other reference rates and the transition process away from LIBOR could adversely impact (i) volatility and liquidity in markets that are tied to those reference rates, (ii) the market for, or value of, specific securities or payments linked to those reference rates, (iii) the availability or terms of borrowing or refinancing, or (iv) the effectiveness of hedging strategies. For these and other reasons, the elimination of LIBOR or other reference rates may adversely affect the Fund’s performance and/or net asset value. Alternatives to LIBOR are established or in development in most major currencies including the Secured Overnight Financing Rate (“SOFR”) that is intended to replace the U.S. dollar LIBOR.The effect of the discontinuation of LIBOR or other reference rates on the Fund will vary depending on, among other things (i) existing fallback or termination provisions in individual contracts and (ii) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new products and instruments. Accordingly, it is difficult to predict the full impact of the transition away from LIBOR or other reference rates on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted.Securities Lending Risk. The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions. There is the risk that when portfolio securities are lent, the securities may not be returned on a timely basis, and the Fund may experience delays and costs in recovering the security or gaining access to the collateral provided to the Fund to collateralize the loan. If the Fund is unable to recover a security on loan, the Fund may use the collateral to purchase replacement securities in the market. There is a risk that the value of the collateral could decrease below the cost of the replacement security by the time the replacement investment is made, resulting in a loss to the Fund.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	<span style="font-family:Times New Roman;font-size:9.50pt;">The biggest risk is that the Fund’s returns will vary, and you could lose money.</span>
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	<span style="color:#000000;font-family:Times New Roman;font-size:9.50pt;font-style:italic;">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.</span>
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:0.0%;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, Class I Shares, and Class R Shares of the Fund commenced operations on July 6, 2009. Class N Shares of the Fund commenced operations on May 31, 2012.•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 R 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.•The performance shown for 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 Class J Shares, net of any applicable fee and expense limitations or waivers.•The performance shown for Class N Shares for periods prior to May 31, 2012, reflects the performance of the Fund’s Class T Shares, calculated using the fees and expenses of Class T Shares, net of any applicable fee and expense limitations or waivers.If Class A Shares, Class C Shares, Class S Shares, Class I Shares, and Class R Shares of the Fund had been available during periods prior to July 6, 2009, or Class N Shares of the Fund had been available during periods prior to May 31, 2012, 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, Class I Shares, Class N Shares, and Class R 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. 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 at janushenderson.com/performance or by calling 1-877-335-2687.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="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. </span><span style="font-family:Times New Roman;font-size:9.50pt;">The bar chart figures do not </span><span style="font-family:Times New Roman;font-size:9.50pt;">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="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="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	<span style="font-family:Times New Roman;font-size:9.50pt;">The bar chart figures do not </span><span style="font-family:Times New Roman;font-size:9.50pt;">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>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter:2nd Quarter 202012.86%Worst Quarter:1st Quarter 2020– 11.56%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (periods ended 12/31/21)
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 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 Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s primary benchmark index is the S&P 500 Index. The Fund also compares its performance to the Bloomberg U.S. Aggregate Bond Index and the Balanced Index. The indices are described below.•The S&P 500 Index is a commonly recognized, market capitalization-weighted index of 500 widely held equity securities, designed to measure broad U.S. equity performance.•The Bloomberg U.S. Aggregate Bond Index is made up of U.S. dollar-denominated, fixed-rate taxable bonds, including securities that are of investment grade quality or better.•The Balanced Index is an internally-calculated, hypothetical combination of unmanaged indices that combines total returns from the S&P 500 Index (55%) and the Bloomberg U.S. Aggregate Bond Index (45%).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 at janushenderson.com/performance or by calling 1-877-335-2687.
Class A C S I N R T Shares | Janus Henderson Balanced Fund | 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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.09%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.89%
1 Year	rr_ExpenseExampleYear01	$ 661
3 Years	rr_ExpenseExampleYear03	843
5 Years	rr_ExpenseExampleYear05	1,040
10 Years	rr_ExpenseExampleYear10	1,608
1 Year	rr_ExpenseExampleNoRedemptionYear01	661
3 Years	rr_ExpenseExampleNoRedemptionYear03	843
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,040
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,608
Class A C S I N R T Shares | Janus Henderson Balanced Fund | 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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.63%
1 Year	rr_ExpenseExampleYear01	$ 266
3 Years	rr_ExpenseExampleYear03	514
5 Years	rr_ExpenseExampleYear05	887
10 Years	rr_ExpenseExampleYear10	1,735
1 Year	rr_ExpenseExampleNoRedemptionYear01	166
3 Years	rr_ExpenseExampleNoRedemptionYear03	514
5 Years	rr_ExpenseExampleNoRedemptionYear05	887
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,735
Class A C S I N R T Shares | Janus Henderson Balanced Fund | 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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.07%
1 Year	rr_ExpenseExampleYear01	$ 109
3 Years	rr_ExpenseExampleYear03	340
5 Years	rr_ExpenseExampleYear05	590
10 Years	rr_ExpenseExampleYear10	1,306
1 Year	rr_ExpenseExampleNoRedemptionYear01	109
3 Years	rr_ExpenseExampleNoRedemptionYear03	340
5 Years	rr_ExpenseExampleNoRedemptionYear05	590
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,306
Class A C S I N R T Shares | Janus Henderson Balanced Fund | 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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.65%
1 Year	rr_ExpenseExampleYear01	$ 66
3 Years	rr_ExpenseExampleYear03	208
5 Years	rr_ExpenseExampleYear05	362
10 Years	rr_ExpenseExampleYear10	810
1 Year	rr_ExpenseExampleNoRedemptionYear01	66
3 Years	rr_ExpenseExampleNoRedemptionYear03	208
5 Years	rr_ExpenseExampleNoRedemptionYear05	362
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 810
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Class N
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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.02%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.57%
1 Year	rr_ExpenseExampleYear01	$ 58
3 Years	rr_ExpenseExampleYear03	183
5 Years	rr_ExpenseExampleYear05	318
10 Years	rr_ExpenseExampleYear10	714
1 Year	rr_ExpenseExampleNoRedemptionYear01	58
3 Years	rr_ExpenseExampleNoRedemptionYear03	183
5 Years	rr_ExpenseExampleNoRedemptionYear05	318
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 714
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Class R
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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.32%
1 Year	rr_ExpenseExampleYear01	$ 134
3 Years	rr_ExpenseExampleYear03	418
5 Years	rr_ExpenseExampleYear05	723
10 Years	rr_ExpenseExampleYear10	1,590
1 Year	rr_ExpenseExampleNoRedemptionYear01	134
3 Years	rr_ExpenseExampleNoRedemptionYear03	418
5 Years	rr_ExpenseExampleNoRedemptionYear05	723
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,590
Class A C S I N R T Shares | Janus Henderson Balanced Fund | 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	0.55%
Distribution/Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.82%
1 Year	rr_ExpenseExampleYear01	$ 84
3 Years	rr_ExpenseExampleYear03	262
5 Years	rr_ExpenseExampleYear05	455
10 Years	rr_ExpenseExampleYear10	1,014
1 Year	rr_ExpenseExampleNoRedemptionYear01	84
3 Years	rr_ExpenseExampleNoRedemptionYear03	262
5 Years	rr_ExpenseExampleNoRedemptionYear05	455
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 1,014
2012	rr_AnnualReturn2012	12.97%
2013	rr_AnnualReturn2013	19.59%
2014	rr_AnnualReturn2014	8.38%
2015	rr_AnnualReturn2015	0.48%
2016	rr_AnnualReturn2016	4.43%
2017	rr_AnnualReturn2017	18.39%
2018	rr_AnnualReturn2018	0.52%
2019	rr_AnnualReturn2019	22.40%
2020	rr_AnnualReturn2020	14.21%
2021	rr_AnnualReturn2021	17.04%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	12.86%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(11.56%)
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.22%	[1]
5 Years	rr_AverageAnnualReturnYear05	12.80%	[1]
10 Years	rr_AverageAnnualReturnYear10	10.80%	[1]
Since Inception	rr_AverageAnnualReturnSinceInception	9.96%	[1]
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992	[1]
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.14%	[2]
5 Years	rr_AverageAnnualReturnYear05	13.35%	[2]
10 Years	rr_AverageAnnualReturnYear10	10.67%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception	9.49%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992	[2]
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.75%
5 Years	rr_AverageAnnualReturnYear05	13.96%
10 Years	rr_AverageAnnualReturnYear10	11.30%
Since Inception	rr_AverageAnnualReturnSinceInception	10.03%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.24%
5 Years	rr_AverageAnnualReturnYear05	14.45%
10 Years	rr_AverageAnnualReturnYear10	11.76%
Since Inception	rr_AverageAnnualReturnSinceInception	10.32%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class N
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.32%
5 Years	rr_AverageAnnualReturnYear05	14.53%
10 Years	rr_AverageAnnualReturnYear10	11.84%
Since Inception	rr_AverageAnnualReturnSinceInception	10.33%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class R
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.46%
5 Years	rr_AverageAnnualReturnYear05	13.68%
10 Years	rr_AverageAnnualReturnYear10	11.02%
Since Inception	rr_AverageAnnualReturnSinceInception	9.79%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return Before Taxes | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.04%
5 Years	rr_AverageAnnualReturnYear05	14.25%
10 Years	rr_AverageAnnualReturnYear10	11.58%
Since Inception	rr_AverageAnnualReturnSinceInception	10.24%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return After Taxes on Distributions | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.76%
5 Years	rr_AverageAnnualReturnYear05	12.99%
10 Years	rr_AverageAnnualReturnYear10	10.27%
Since Inception	rr_AverageAnnualReturnSinceInception	8.81%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.83%
5 Years	rr_AverageAnnualReturnYear05	11.09%
10 Years	rr_AverageAnnualReturnYear10	9.12%
Since Inception	rr_AverageAnnualReturnSinceInception	8.27%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 1992
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class N
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class R
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | S&P 500® Index (reflects no deduction for expenses, fees, or taxes) | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.71%
5 Years	rr_AverageAnnualReturnYear05	18.47%
10 Years	rr_AverageAnnualReturnYear10	16.55%
Since Inception	rr_AverageAnnualReturnSinceInception	10.84%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class N
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class R
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Bloomberg U.S. Aggregate Bond Index (reflects no deduction for expenses, fees, or taxes) | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	3.57%
10 Years	rr_AverageAnnualReturnYear10	2.90%
Since Inception	rr_AverageAnnualReturnSinceInception	5.20%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class A
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class C
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class S
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class I
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class N
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class R
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%
Class A C S I N R T Shares | Janus Henderson Balanced Fund | Balanced Index (reflects no deduction for expenses, fees, or taxes) | Class T
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.32%
5 Years	rr_AverageAnnualReturnYear05	11.87%
10 Years	rr_AverageAnnualReturnYear10	10.46%
Since Inception	rr_AverageAnnualReturnSinceInception	8.57%

[1] Calculated assuming maximum permitted sales loads.

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