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Vanguard California Municipal Money Market 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
California Tax-Exempt Money Market Funds Average[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 2.14% 1.68% 1.08%
Investor Shares      
Prospectus [Line Items]      
Average Annual Return, Percent 2.17% 1.70% 1.23%