Vanguard Inflation-Protected Securities Fund Average Annual Total Returns - Institutional Prospectus [Member] |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. Treasury Inflation Protected Securities Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.01% | 1.12% | 3.09% |
| Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.30% | (0.36%) | 2.01% |
| Institutional Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 6.98% | 1.06% | 3.01% |
| Institutional Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.96% | (1.07%) | 1.43% |
| Institutional Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.12% | (0.11%) | 1.63% |