Vanguard Long-Term Bond Index Fund Annual Total Returns |
12 Months Ended | |||||
|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Admiral Prospectus [Member] | Vanguard Long-Term Bond Index Fund | Admiral Shares | ||||||
| Prospectus [Line Items] | ||||||
| Annual Return [Percent] | 6.56% | (4.16%) | 7.52% | (27.22%) | (2.66%) | 16.23% |