Vanguard Federal Money Market Fund Expense Example - Retail Prospectus [Member] - Vanguard Federal Money Market Fund - Investor Shares	Aug. 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 11
Expense Example, with Redemption, 3 Years	35
Expense Example, with Redemption, 5 Years	62
Expense Example, with Redemption, 10 Years	$ 141

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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