Vanguard Short-Term Treasury Fund Average Annual Total Returns - Retail 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 Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.84% | 1.28% | 1.82% |
| 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% |
| Investor Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.35% | 1.33% | 1.69% |
| Investor Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 3.69% | 0.14% | 0.71% |
| Investor Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 3.15% | 0.50% | 0.87% |
| Admiral Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.45% | 1.44% | 1.79% |