Vanguard Cash Reserves Federal Money Market Fund Investment Objectives and Goals - Retail Prospectus [Member] - Vanguard Cash Reserves Federal Money Market Fund	Aug. 31, 2025
Prospectus [Line Items]
Risk/Return [Heading]	<span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Vanguard Cash Reserves Federal Money Market Fund</span>
Objective [Heading]	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	Vanguard Cash Reserves Federal Money Market Fund (the “Fund”) seeks to provide current income while maintaining liquidity and a stable share price of $1.