Vanguard Market Liquidity Fund Performance Management - Investor Prospectus [Member] - Vanguard Market Liquidity Fund |
Aug. 31, 2025 |
|---|---|
| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Annual Total Returns</span> |
| Performance Narrative [Text Block] | The following bar chart and table show the Fund’s historical performance and are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund compare with those of a relevant peer group average. Returns for the U.S. Government Money Market Funds Average are derived from data provided by Lipper, a Thomson Reuters Company. Information regarding the former benchmark, the Institutional Money Market Funds Average, derived from data provided by Lipper, a Thomson Reuters Company, is also provided. Prior to June 5, 2024, the Fund operated as an institutional prime money market fund and invested in certain types of securities that the Fund is no longer permitted to hold. Consequently, the performance information below may have been different if the current investment limitation had been in effect during the period prior to the Fund’s conversion to a government money market fund. Keep in mind that the Fund’s past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance. |
| Performance Past Does Not Indicate Future [Text] | <span style="color:#000000;font-family:Arial;font-size:9.5pt;">Keep in mind that the Fund’s past </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">performance does not indicate how the Fund will perform in the future.</span> |
| Performance Information Illustrates Variability of Returns [Text] | <span style="color:#000000;font-family:Arial;font-size:9.5pt;">The following bar chart and table show the Fund’s historical performance and are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Fund compare with those of a relevant peer group average.</span> |
| Bar Chart [Heading] | <span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;">Annual Total Returns — Vanguard Market Liquidity Fund Investor Shares</span> |
| Bar Chart Closing [Text Block] | The highest and lowest returns for a calendar quarter during the periods shown in the bar chart and the year-to-date return as of the most recent calendar quarter were: |
| Performance Table Heading | <span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Average Annual Total Returns for Periods Ended December 31, 2024</span> |
| Performance Availability Website Address [Text] | <span style="color:#000000;font-family:Arial;font-size:9.5pt;font-style:italic;">vanguard.com/performance</span> |
| Investor Shares | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | <span style="color:#000000;font-family:Arial;font-size:8pt;margin-left:0.0pt;">Year-to-Date Return</span> |
| Bar Chart, Year to Date Return | 3.30% |
| Bar Chart, Year to Date Return, Date | Sep. 30, 2025 |
| Highest Quarterly Return, Label [Optional Text] | <span style="color:#000000;font-family:Arial;font-size:8pt;margin-left:0.0pt;">Highest</span> |
| Highest Quarterly Return | 1.37% |
| Highest Quarterly Return, Date | Dec. 31, 2023 |
| Lowest Quarterly Return, Label [Optional Text] | <span style="color:#000000;font-family:Arial;font-size:8pt;margin-left:0.0pt;">Lowest</span> |
| Lowest Quarterly Return | 0.01% |
| Lowest Quarterly Return, Date | Dec. 31, 2021 |