Vanguard Extended Duration Treasury Index Fund Annual Fund Operating Expenses - Institutional Prospectus [Member] - Vanguard Extended Duration Treasury Index Fund |
Aug. 31, 2025 |
|---|---|
| Institutional Shares | |
| Prospectus [Line Items] | |
| Management Fees (as a percentage of Assets) | 0.05% |
| Distribution and Service (12b-1) Fees | 0.00% |
| Other Expenses (as a percentage of Assets): | 0.00% |
| Expenses (as a percentage of Assets) | 0.05% |
| Institutional Plus Shares | |
| Prospectus [Line Items] | |
| Management Fees (as a percentage of Assets) | 0.02% |
| Distribution and Service (12b-1) Fees | 0.00% |
| Other Expenses (as a percentage of Assets): | 0.01% |
| Expenses (as a percentage of Assets) | 0.03% |