Vanguard Short-Term Bond Index Fund Average Annual Total Returns - Investor Prospectus [Member] |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. 1-5 Year Gov/Credit Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 6.11% | 1.56% | 2.17% |
| Bloomberg U.S. Aggregate Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.21% | (0.37%) | 2.05% |
| Investor Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.98% | 1.43% | 2.02% |
| Investor Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.37% | 0.45% | 1.16% |
| Investor Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 3.52% | 0.67% | 1.17% |