Janus Henderson Short Duration Flexible Bond Fund Investment Strategy - Class A C S I N T Shares [Member] - Janus Henderson Short Duration Flexible Bond Fund	Jun. 30, 2025
Prospectus [Line Items]
Strategy [Heading]	<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]	The Fund invests, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in short- and intermediate-term securities such as corporate bonds or notes or government securities, including agency securities, commercial and residential mortgage-backed securities, and asset-backed securities. The Fund may invest in fixed and floating rate obligations with varying durations and credit risk transfer securities (“CRTs”). The Fund will invest at least 65% of its net assets in investment grade debt securities. The Fund may invest up to 35% of its net assets in high-yield bonds (also known as “junk” bonds). The Fund’s investments in short-term securities may include money market instruments. The Fund may enter into “to be announced” or “TBA” commitments when purchasing mortgage-backed securities or other securities, and may also invest in inflation-linked securities, including Treasury Inflation-Protected Securities, also known as TIPS. The Fund may also invest in securities that have contractual restrictions that prohibit or limit their public resale, which may include Rule 144A securities. The Fund may also invest in foreign securities. Due to the nature of the securities in which the Fund invests, it may have relatively high portfolio turnover compared to other funds. The Fund’s average portfolio duration typically ranges between one and three years. As of June 30, 2025, the Fund’s average portfolio duration was 2.05 years. Additionally, the Fund may invest its assets in derivatives. Derivative instruments have a value derived from, or directly linked to, an underlying asset, such as fixed-income securities, commodities, currencies, interest rates, or market indices. In particular, the Fund may use 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, and to earn income, enhance returns, or preserve capital. The Fund’s exposure to derivatives will vary. For purposes of meeting its 80% investment policy, the Fund may include derivatives that have characteristics similar to the securities in which the Fund may directly invest. The Fund may engage in short sales of derivatives instruments. Portfolio management’s investment process is research-driven, incorporating “top-down” and “bottom-up” factors to identify and manage exposure to risks across sectors, industries, and individual investments. Portfolio management evaluates expected risk-adjusted returns on a portfolio and position level by analyzing fundamentals, valuations, and market technical indicators. This research encompasses both traditional fundamental analysis and data driven quantitative models and signals from such models.As part of its investment process, portfolio management considers environmental, social, and governance (“ESG”) risks and opportunities (“ESG Factors”) that it believes are financially material, alongside other fundamental investment factors. Examples of potential financially material ESG Factors include: corporate governance, company culture, exposure to climate change, and human capital management. To assess ESG Factors, portfolio management uses issuer reports, third-party data, and internally-generated analyses and may engage directly with issuers. ESG Factors are one of many considerations in the investment decision-making process, may not be determinative in deciding to include or exclude an investment from the portfolio, and may not be considered for every investment decision.The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions, in an amount equal to up to one-third of its total assets as determined at the time of the loan origination.

Janus Henderson Short Duration Flexible Bond Fund Investment Strategy - Class A C S I N T Shares [Member] - Janus Henderson Short Duration Flexible Bond Fund

Jun. 30, 2025

<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]

The Fund invests, under normal circumstances, at least 80% of its net assets (plus any borrowings for investment purposes) in short- and intermediate-term securities such as corporate bonds or notes or government securities, including agency securities, commercial and residential mortgage-backed securities, and asset-backed securities. The Fund may invest in fixed and floating rate obligations with varying durations and credit risk transfer securities (“CRTs”). The Fund will invest at least 65% of its net assets in investment grade debt securities. The Fund may invest up to 35% of its net assets in high-yield bonds (also known as “junk” bonds). The Fund’s investments in short-term securities may include money market instruments. The Fund may enter into “to be announced” or “TBA” commitments when purchasing mortgage-backed securities or other securities, and may also invest in inflation-linked securities, including Treasury Inflation-Protected Securities, also known as TIPS. The Fund may also invest in securities that have contractual restrictions that prohibit or limit their public resale, which may include Rule 144A securities. The Fund may also invest in foreign securities. Due to the nature of the securities in which the Fund invests, it may have relatively high portfolio turnover compared to other funds. The Fund’s average portfolio duration typically ranges between one and three years. As of June 30, 2025, the Fund’s average portfolio duration was 2.05 years. Additionally, the Fund may invest its assets in derivatives. Derivative instruments have a value derived from, or directly linked to, an underlying asset, such as fixed-income securities, commodities, currencies, interest rates, or market indices. In particular, the Fund may use 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, and to earn income, enhance returns, or preserve capital. The Fund’s exposure to derivatives will vary. For purposes of meeting its 80% investment policy, the Fund may include derivatives that have characteristics similar to the securities in which the Fund may directly invest. The Fund may engage in short sales of derivatives instruments. Portfolio management’s investment process is research-driven, incorporating “top-down” and “bottom-up” factors to identify and manage exposure to risks across sectors, industries, and individual investments. Portfolio management evaluates expected risk-adjusted returns on a portfolio and position level by analyzing fundamentals, valuations, and market technical indicators. This research encompasses both traditional fundamental analysis and data driven quantitative models and signals from such models.As part of its investment process, portfolio management considers environmental, social, and governance (“ESG”) risks and opportunities (“ESG Factors”) that it believes are financially material, alongside other fundamental investment factors. Examples of potential financially material ESG Factors include: corporate governance, company culture, exposure to climate change, and human capital management. To assess ESG Factors, portfolio management uses issuer reports, third-party data, and internally-generated analyses and may engage directly with issuers. ESG Factors are one of many considerations in the investment decision-making process, may not be determinative in deciding to include or exclude an investment from the portfolio, and may not be considered for every investment decision.The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions, in an amount equal to up to one-third of its total assets as determined at the time of the loan origination.