Vanguard Intermediate-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. 5-10 Year Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 8.18% | (0.86%) | 1.62% |
| 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 | 7.53% | (0.14%) | 1.71% |
| Investor Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.82% | (1.30%) | 0.57% |
| Investor Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.43% | (0.61%) | 0.83% |
| Admiral Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.63% | (0.04%) | 1.82% |