Investment Strategy - Morgan Stanley Institutional Liquidity Funds - MSILF Treasury Securities Portfolio	Oct. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	The Fund has adopted a policy to invest exclusively in U.S. Treasury obligations, which are backed by the full faith and credit of the United States, and, accordingly, qualifies as a “government money market fund” under federal regulations. The Fund is permitted to hold a portion of its assets in cash. A “government money market fund” is a money market fund that invests at least 99.5% of its total assets in cash, securities issued or guaranteed by the United States or certain U.S. government agencies or instrumentalities and/or repurchase agreements that are collateralized fully by the foregoing. A “government money market fund” is exempt from requirements that permit and, under certain circumstances, require money market funds to impose a “liquidity fee” on redemptions. In selecting investments, the Adviser seeks to maintain the Fund’s share price at $1.00. The share price remaining stable at $1.00 means that the Fund would preserve the principal value of your investment. As a “government money market fund,” the Fund may value its securities using the amortized cost method as permitted by Rule 2a-7 under the Investment Company Act of 1940, as amended (“Rule 2a-7” under the “1940 Act”) to seek to maintain a stable net asset value per share of $1.00. In addition, the Fund has adopted a policy that provides, under normal circumstances, at least 80% of the Fund’s assets will be invested in U.S. Treasury obligations, which are backed by the full faith and credit of the United States. This policy may be changed without shareholder approval; however, shareholders would be notified upon 60 days’ notice in writing of any changes. The Fund’s investments are subject to the quality, diversification, maturity, liquidity and other requirements of Rule 2a-7.

The Fund has adopted a policy to invest exclusively in U.S. Treasury obligations, which are backed by the full faith and credit of the United States, and, accordingly, qualifies as a “government money market fund” under federal regulations. The Fund is permitted to hold a portion of its assets in cash.

A “government money market fund” is a money market fund that invests at least 99.5% of its total assets in cash, securities issued or guaranteed by the United States or certain U.S. government agencies or instrumentalities and/or repurchase agreements that are collateralized fully by the foregoing. A “government money market fund” is exempt from requirements that permit and, under certain circumstances, require money market funds to impose a “liquidity fee” on redemptions. In selecting investments, the Adviser seeks to maintain the Fund’s share price at $1.00. The share price remaining stable at $1.00 means that the Fund would preserve the principal value of your investment. As a “government money market fund,” the Fund may value its securities using the amortized cost method as permitted by Rule 2a-7 under the Investment Company Act of 1940, as amended (“Rule 2a-7” under the “1940 Act”) to seek to maintain a stable net asset value per share of $1.00.

In addition, the Fund has adopted a policy that provides, under normal circumstances, at least 80% of the Fund’s assets will be invested in U.S. Treasury obligations, which are backed by the full faith and credit of the United States. This policy may be changed without shareholder approval; however, shareholders would be notified upon 60 days’ notice in writing of any changes.