Janus Henderson Money Market Fund Investment Strategy - Class D Shares [Member] - Janus Henderson Money Market Fund	Jun. 30, 2026
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 pursues its investment objectives by investing primarily in high quality debt obligations and obligations of financial institutions. Debt obligations may include commercial paper, notes, and bonds. Obligations of financial institutions include certificates of deposit and time deposits. The Fund also intends to invest in repurchase agreements including those secured by U.S. Government agencies. Some government agencies backed by the full faith and credit of the United States are supported by the issuer’s ability to borrow from the U.S. Treasury, some are supported only by the credit of the issuer, and some are supported by the United States in some other way.The Fund will: •invest in high-quality, short-term money market instruments that present minimal credit risks, as determined by the Adviser •invest only in U.S. dollar-denominated instruments that have a remaining maturity of 397 days or less (as calculated pursuant to Rule 2a-7 under the Investment Company Act of 1940, as amended) •maintain a dollar-weighted average portfolio maturity of 60 days or less and maintain a dollar-weighted average portfolio life (portfolio maturity measured without reference to any maturity shortening provisions of adjustable rate securities by reference to their interest rate reset dates) of 120 days or less

Janus Henderson Money Market Fund Investment Strategy - Class D Shares [Member] - Janus Henderson Money Market Fund

Jun. 30, 2026

<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 pursues its investment objectives by investing primarily in high quality debt obligations and obligations of financial institutions. Debt obligations may include commercial paper, notes, and bonds. Obligations of financial institutions include certificates of deposit and time deposits. The Fund also intends to invest in repurchase agreements including those secured by U.S. Government agencies. Some government agencies backed by the full faith and credit of the United States are supported by the issuer’s ability to borrow from the U.S. Treasury, some are supported only by the credit of the issuer, and some are supported by the United States in some other way.The Fund will: •invest in high-quality, short-term money market instruments that present minimal credit risks, as determined by the Adviser •invest only in U.S. dollar-denominated instruments that have a remaining maturity of 397 days or less (as calculated pursuant to Rule 2a-7 under the Investment Company Act of 1940, as amended) •maintain a dollar-weighted average portfolio maturity of 60 days or less and maintain a dollar-weighted average portfolio life (portfolio maturity measured without reference to any maturity shortening provisions of adjustable rate securities by reference to their interest rate reset dates) of 120 days or less