Vanguard Federal Money Market Fund Average Annual Total Returns - Retail Prospectus [Member] |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2024 |
Dec. 31, 2024 |
|
| FTSE 3-Month U.S. Treasury Bill Index (reflects no deduction for fees or expenses)[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.45% | 2.54% | 1.79% |
| U.S. Government Money Market Funds Average[Member] | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.73% | 2.15% | 1.39% |
| Investor Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.23% | 2.44% | 1.72% |