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Vanguard Short-Term Federal 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 Government Bond Index (reflects no deduction for fees, expenses, or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 5.83% 1.29% 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 5.82% 1.50% 1.89%
Investor Shares | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 4.23% 0.40% 0.98%
Investor Shares | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 3.43% 0.67% 1.06%
Admiral Shares      
Prospectus [Line Items]      
Average Annual Return, Percent 5.93% 1.60% 2.00%