Vanguard Long-Term Bond Index Fund Expense Example - Institutional Prospectus [Member] - Vanguard Long-Term Bond Index Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Institutional Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 53 |
| Expense Example, with Redemption, 3 Years | 60 |
| Expense Example, with Redemption, 5 Years | 67 |
| Expense Example, with Redemption, 10 Years | 88 |
| Institutional Plus Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 52 |
| Expense Example, with Redemption, 3 Years | 56 |
| Expense Example, with Redemption, 5 Years | 61 |
| Expense Example, with Redemption, 10 Years | $ 76 |