Vanguard Extended Duration Treasury Index Fund Investment Objectives and Goals - ETF Prospectus [Member] - Vanguard Extended Duration Treasury Index Fund |
Aug. 31, 2025 |
|---|---|
| Prospectus [Line Items] | |
| Risk/Return [Heading] | <span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Fund Summary</span> |
| Objective [Heading] | <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span> |
| Objective, Primary [Text Block] | Vanguard Extended Duration Treasury ETF, an exchange-traded share class of Vanguard Extended Duration Treasury Index Fund (the “Fund”), seeks to track the performance of an index of extended-duration zero-coupon U.S. Treasury securities. |