Vanguard GNMA 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. GNMA Bond Index (reflects no deduction for fees, expenses, or taxes)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 8.08% | 0.23% | 1.50% |
| 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 | 7.72% | 0.19% | 1.49% |
| Investor Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 6.12% | (0.91%) | 0.38% |
| Investor Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.54% | (0.34%) | 0.65% |
| Admiral Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.82% | 0.29% | 1.59% |