Vanguard Intermediate-Term Bond Index Fund Average Annual Total Returns - Admiral Prospectus [Member] |
12 Months Ended | 60 Months Ended | 83 Months Ended | 120 Months Ended |
|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. 5-10 Year Gov/Credit Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)[Member] | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 8.76% | (0.15%) | 2.55% | |
| 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%) | 1.90% | 2.05% |
| Admiral Shares | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 8.56% | (0.20%) | 2.47% | |
| Admiral Shares | After Taxes on Distributions | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 6.78% | (1.49%) | 1.22% | |
| Admiral Shares | After Taxes on Distributions and Sales | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 5.03% | (0.69%) | 1.38% |