v3.25.2
Label Element Value
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds)  
Prospectus [Line Items] oef_ProspectusLineItems  
Objective [Heading] oef_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] oef_ObjectivePrimaryTextBlock
The Treasury Portfolio (the “Fund”) seeks preservation of capital, daily liquidity and maximum current income.
Expense Heading [Optional Text] oef_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] oef_ExpenseNarrativeTextBlock
The table below describes the expenses that you may pay if you buy, hold and sell Institutional Plus Class shares of the Fund. The Fund does not charge any sales loads or other fees when you purchase or redeem shares. You may pay fees other than the fees and expenses of the Fund, such as brokerage commissions and other fees charged by financial intermediaries, which are not reflected in the tables and examples below.
Operating Expenses Caption [Optional Text] oef_OperatingExpensesCaption Annual Fund Operating Expenses  (expenses that you pay each year as a percentage of the value of your investment)
Other Expenses, New Fund, Based on Estimates [Text] oef_OtherExpensesNewFundBasedOnEstimates Other Expenses have been estimated for the current fiscal year.
Expense Example [Heading] oef_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] oef_ExpenseExampleNarrativeTextBlock
The example below is intended to help you compare the cost of investing in the Fund’s  Institutional Plus  Class with the cost of investing in other mutual funds.
The example assumes that you invest $10,000 in the Fund’s  Institutional Plus Class for the time periods indicated and then redeem all of your shares at the end of those periods, your investment has a 5% return each year and that the Fund’s operating expenses remain the same (except that the example incorporates the fee waiver and/or expense reimbursement arrangement for only the first year). Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading] oef_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] oef_StrategyNarrativeTextBlock
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 repurchase agreements collateralized by such securities, 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.
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, and repurchase agreements collateralized by such securities. This policy may be changed without shareholder approval; however, shareholders would be notified upon 60 days’ notice in writing of any changes.
Bar Chart and Performance Table [Heading] oef_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] oef_PerformanceNarrativeTextBlock
The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the performance of the Fund’s Institutional Select Class shares from year-to-year and by showing the average annual returns of the Fund’s Institutional Select Class shares for the one, five and 10 year periods. The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available online at www.morganstanley.com/liquidity.
Performance Information Illustrates Variability of Returns [Text] oef_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the performance of the Fund’s Institutional Select Class shares from year-to-year and by showing the average annual returns of the Fund’s Institutional Select Class shares for the one, five and 10 year periods.
Performance Availability Website Address [Text] oef_PerformanceAvailabilityWebSiteAddress www.morganstanley.com/liquidity
Performance Past Does Not Indicate Future [Text] oef_PerformancePastDoesNotIndicateFuture The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] oef_BarChartHeading Annual Total Returns—Calendar Years
Bar Chart Closing [Text Block] oef_BarChartClosingTextBlock
High Quarter
12/31/23
1.30%
Low Quarter
03/31/21
0.00%
The year-to-date total return as of  June 30, 2025 was 2.07%.
Performance Table Heading oef_PerformanceTableHeading Average Annual Total Returns (for the Periods Ended  December 31, 2024)
Performance Table Closing [Text Block] oef_PerformanceTableClosingTextBlock
You may obtain the Fund’s 7-day current yield by calling 1-888-378-1630.
Money Market Seven Day Yield, Caption [Optional Text] oef_MoneyMarketSevenDayYieldCaption You may obtain the Fund’s 7-day current yield by calling 1-888-378-1630.
Money Market Seven Day Yield Phone oef_MoneyMarketSevenDayYieldPhone 1-888-378-1630
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Risk Lose Money [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock You could lose money by investing in the Fund.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Credit and Interest Rate Risk [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Credit and Interest Rate Risk. Credit risk refers to the possibility that the issuer or guarantor of a security, or counterparty to a transaction, will be unable or unwilling or perceived to be unable or unwilling to make interest payments and/or repay the principal on its debt or otherwise honor its obligations, including the risk of default. In such instances, the value of the Fund could decline and the Fund could lose money. If an issuer’s, guarantor’s or counterparty’s financial condition worsens, the credit quality of the issuer, guarantor or counterparty may deteriorate. Credit ratings may not be an accurate assessment of financial condition, liquidity or credit risk. Although credit ratings may not accurately reflect the true credit risk of an instrument, a change in the credit rating of an instrument or an issuer, guarantor or counterparty, or the market’s perception of the creditworthiness of an instrument or issuer, guarantor or counterparty can have a rapid, adverse effect on the instrument’s value and liquidity and make it more difficult for the Fund to sell at an advantageous price or time. Interest rate risk refers to the decline in the value of a fixed-income security resulting from changes in the general level of interest rates. A wide variety of market and economic factors can cause interest rates to rise or fall, including central bank monetary policy, rising inflation, disinflation or deflation, and changes in general economic conditions. When the general level of interest rates goes up, the prices of most fixed-income securities go down. When the general level of interest rates goes down, the prices of most fixed-income securities go up but the yield or income from new issuances of fixed-income securities generally decreases. Securities with longer durations will generally be more sensitive to changes in interest rates than securities with shorter durations. Fluctuations in interest rates may also affect the liquidity of and income generated by fixed-income instruments held by the Fund. The Fund may face a heightened level of interest rate risk in times of monetary policy change and/or uncertainty, such as when the Federal Reserve Board adjusts a quantitative easing program and/or changes rates. Changing interest rates may have unpredictable effects on the markets and may detract from Fund performance. A changing interest rate environment increases certain risks, including the potential for periods of market volatility and increased redemptions.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Fixed Income Securities [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Fixed-Income Securities. Fixed-income securities are subject to the risk of the issuer’s inability to meet principal and interest payments on its obligations (i.e., credit risk) and are subject to price volatility resulting from, among other things, interest rate sensitivity (i.e., interest rate risk), market perception of the creditworthiness of the issuer and general market liquidity (i.e., market risk). Securities with longer durations are likely to be more sensitive to changes in interest rates, generally making them more volatile than securities with shorter durations. The Fund may be subject to certain liquidity risks that may result from the lack of an active market and the reduced number and capacity of traditional market participants to make a market in fixed-income securities.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | U.S. Government Securities [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
U.S. Government Securities.  Different types of U.S. government securities are subject to different levels of credit risk, including the risk of default, depending on the nature of the particular government support for that security. For example, a U.S. government-sponsored entity, such as Federal National Mortgage Association or Federal Home Loan Mortgage Corporation, although chartered or sponsored by an Act of Congress, may issue securities that are neither insured nor guaranteed by the U.S. Treasury and, therefore, are not backed by the full faith and credit of the United States. With respect to U.S. government securities that are not backed by the full faith and credit of the United States, there is the risk that the U.S. government will not provide financial support to such U.S. government agencies, instrumentalities or sponsored enterprises if it is not obligated to do so by law. U.S. government securities are also subject to interest rate risks and can exhibit price fluctuations resulting from increases or decreases in interest rates.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Repurchase Agreements [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Repurchase Agreements. Repurchase agreements are subject to risks associated with the possibility of default by the seller at a time when the collateral has declined in value, or insolvency of the seller, which may affect the Fund’s right to control the collateral and result in certain costs and delays. Repurchase agreements may involve a greater degree of credit risk than investments in U.S. government securities.  
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Market and Geopolitical Risk [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic and other events that affect the  U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact the Fund’s ability to sell securities and/or its ability to meet redemptions. The risks associated with these developments may be magnified if certain social, political, economic and other conditions and events (such as war, natural disasters or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes and supply chain disruptions) adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may
negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value of the Fund’s investments, adversely affect the Fund’s ability to maintain a stable $1.00 share price and exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Large Transactions Risk [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Large Transactions Risk. The Fund may experience adverse effects when certain large shareholders, or a number of shareholders collectively, purchase or redeem large amounts of shares of the Fund, which may occur rapidly or unexpectedly. Such larger than normal shareholder redemptions may affect the Fund’s ability to maintain a stable $1.00 share price and negatively impact the Fund’s liquidity. In some circumstances, the Fund may hold a relatively large proportion of its assets in cash in anticipation of large redemptions. These large redemptions may also force the Fund to sell portfolio securities or other assets when it might not otherwise do so, which may affect the Fund’s ability to maintain a stable $1.00 share price and increase the Fund’s transaction costs. In addition, large purchases of Fund shares may adversely affect the Fund’s performance to the extent that the Fund is delayed in investing new cash and is required to maintain a larger cash position than it ordinarily would. Finally, large redemptions may cause the Fund to impose a discretionary liquidity fee.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Stable NAV Risk [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Stable NAV Risk. The Fund may not be able to maintain a stable $1.00 share price at all times. If the Fund or another money market fund fails to maintain a stable NAV (or if there is a perceived threat of the inability to maintain a stable NAV), the Fund could be subject to increased redemptions, which may adversely impact the Fund’s ability to maintain a stable $1.00 share price.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Active Management Risk [Member]  
Prospectus [Line Items] oef_ProspectusLineItems  
Risk [Text Block] oef_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
Treasury Portfolio | (Morgan Stanley Institutional Liquidity Funds) | Institutional Plus Class  
Prospectus [Line Items] oef_ProspectusLineItems  
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.15%
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Shareholder Administration Fee oef_Component1OtherExpensesOverAssets 0.02%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.06% [1]
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.23% [2]
Fee Waiver or Reimbursement oef_FeeWaiverOrReimbursementOverAssets 0.01% [2]
Net Expenses (as a percentage of Assets) oef_NetExpensesOverAssets 0.22% [2]
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 23
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 73
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 129
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 292
Year to Date Return, Label [Optional Text] oef_YearToDateReturnLabel The year-to-date total return as of  June 30, 2025 was 2.07%
Bar Chart, Year to Date Return, Date oef_BarChartYearToDateReturnDate Jun. 30, 2025
Bar Chart, Year to Date Return oef_BarChartYearToDateReturn 2.07%
Highest Quarterly Return, Label [Optional Text] oef_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return, Date oef_BarChartHighestQuarterlyReturnDate Dec. 31, 2023
Highest Quarterly Return oef_BarChartHighestQuarterlyReturn 1.30%
Lowest Quarterly Return, Label [Optional Text] oef_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return, Date oef_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return oef_BarChartLowestQuarterlyReturn none
(Morgan Stanley Institutional Liquidity Funds) | Institutional Plus Class  
Prospectus [Line Items] oef_ProspectusLineItems  
Annual Return [Percent] oef_AnnlRtrPct 0.03%
Annual Return [Percent] oef_AnnlRtrPct 0.18%
Annual Return [Percent] oef_AnnlRtrPct 0.71%
Annual Return [Percent] oef_AnnlRtrPct 1.69%
Annual Return [Percent] oef_AnnlRtrPct 2.01%
Annual Return [Percent] oef_AnnlRtrPct 0.29%
Annual Return [Percent] oef_AnnlRtrPct 0.01%
Annual Return [Percent] oef_AnnlRtrPct 1.47%
Annual Return [Percent] oef_AnnlRtrPct 4.93%
Annual Return [Percent] oef_AnnlRtrPct 5.07%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.07% [3]
Average Annual Return, Percent oef_AvgAnnlRtrPct 2.33% [3]
Average Annual Return, Percent oef_AvgAnnlRtrPct 1.62% [3]
[1] Other Expenses have been estimated for the current fiscal year.
[2] The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc. (“MSIM”), has agreed to reduce its advisory fee, its administration fee and/or reimburse the Fund’s Institutional Plus Class so that Total Annual Fund Operating Expenses, excluding acquired fund fees and expenses (as applicable), certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 0.22%. The fee waivers and/or expense reimbursements will continue for at least one year from the date of this Prospectus or until such time as the Board of Trustees of Morgan Stanley Institutional Liquidity Funds (the “Trust”) acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[3] Institutional Select Class shares are not offered in this Prospectus. Institutional Plus Class shares of the Fund had not completed a full calendar year of operations as of December 31, 2024 and therefore Institutional Plus Class shares do not have annualized return information to report. Institutional Plus Class shares would have substantially similar annual returns because the shares are invested in the same portfolio of securities and the annual returns would differ only to the extent that the Classes do not have the same expenses. Return information for the Fund’s Institutional Plus Class shares will be shown in future prospectuses offering the Fund’s Institutional Plus Class shares after the Fund’s Institutional Plus Class shares have a full calendar year of return information to report.