Janus Henderson Adaptive Risk Managed U.S. Equity Fund Investment Risks - Class A C S I N T Shares [Member] - Janus Henderson Adaptive Risk Managed U.S. Equity Fund	Jun. 30, 2025
Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Risk. The value of the Fund’s portfolio may decrease due to short-term market movements and over more prolonged market downturns. As a result, the Fund’s net asset value may fluctuate and it may be more difficult to value or sell the 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 financial institution failures, economic recessions, tariffs, trade disputes, terrorism, war, armed conflicts, including related sanctions, social unrest, natural disasters, and epidemics and pandemics) 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.
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. 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. 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 or perceptions regarding the industries in which the issuers of securities the Fund holds participate.
Industry and Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Industry and Sector Risk. Although the Fund does not concentrate its investments in specific industries, it may have a significant portion of its assets invested in securities of companies conducting similar business or businesses within the same economic sector. Companies in the same industry or economic sector may be similarly affected by negative economic or market events, making the Fund more vulnerable to unfavorable developments than funds that invest more broadly. As the Fund’s portfolio becomes more concentrated, the Fund is less able to spread risk and potentially reduce the risk of loss and volatility. As the Fund’s holdings change over time, the Fund’s exposure to a particular economic sector may fluctuate.
Technology Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	•Technology Sector Risk. In the technology sector, competitive pressures may have a significant effect on the performance of companies in which the Fund may invest. In addition, technology and technology-related companies often progress at an accelerated rate, and these companies may be subject to short product cycles and aggressive pricing, which may increase their volatility.
Large Sized Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Large-Sized Companies Risk. Large-sized companies may be less able than smaller-sized companies to adapt to changing market conditions. Large-sized companies may be more mature and subject to more limited growth potential compared with smaller sized companies. During different market cycles, the performance of large-sized companies has trailed the overall performance of the broader securities markets.
Mid-Sized Companies Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Mid-Sized Companies Risk. Investments in securities issued by mid-sized companies may involve greater risks than are customarily associated with larger, more established companies. Securities issued by mid-sized companies tend to be more volatile than securities issued by larger or more established companies and may underperform as compared to the securities of larger or more established companies. These holdings are also subject to wider price fluctuations and tend to be less liquid than stocks of larger or more established companies, which could have a significant adverse effect on the Fund’s returns, especially as market conditions change.
Portfolio Management Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	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. Accordingly, the Fund may underperform benchmark indices or other funds with similar investment objectives.
Portfolio Turnover Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Portfolio Turnover Risk. Increased portfolio turnover may result in higher costs, which may offset gains or increase losses in the Fund’s performance. In addition, higher portfolio turnover may result in the acceleration of capital gains and the recognition of greater levels of short-term capital gains, which are taxed at ordinary federal income tax rates when distributed to shareholders.
Depositary Receipts Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Depositary Receipts Risk. Depositary receipts are generally subject to the same sort of risks as direct investments in a foreign country, such as currency risk, market risk, and foreign exposure risk, because their values depend on the performance of a foreign security denominated in its home currency.
Volatility Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Volatility Risk. There is no guarantee that the Fund’s strategy to minimize volatility will be successful. Securities in the 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 Fund’s strategy to minimize volatility could limit the Fund’s gains in rising markets.
Securities Lending Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Securities Lending Risk. 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.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	The biggest risk is that the Fund’s returns will vary, and you could lose money.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	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.