v3.26.1
Shareholder Report, Holdings (Details)
Mar. 31, 2026
American Funds® U.S. Government Money Market Fund - Class A  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class A | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class A | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class A | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class A | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class A | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class C  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class C | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class C | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class C | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class C | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class C | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class T  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class T | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class T | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class T | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class T | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class T | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class F-1  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class F-1 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class F-1 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class F-1 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class F-1 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class F-1 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class F-2  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class F-2 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class F-2 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class F-2 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class F-2 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class F-2 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class F-3  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class F-3 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class F-3 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class F-3 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class F-3 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class F-3 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-A  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-A | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-A | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-A | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-A | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-A | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-C  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-C | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-C | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-C | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-C | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-C | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-E  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-E | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-E | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-E | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-E | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-E | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-T  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-T | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-T | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-T | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-T | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-T | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-F-1  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-F-1 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-F-1 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-F-1 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-F-1 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-F-1 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-F-2  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-F-2 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-F-2 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-F-2 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-F-2 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-F-2 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class 529-F-3  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class 529-F-3 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class 529-F-3 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class 529-F-3 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class 529-F-3 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class 529-F-3 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class ABLE-A  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class ABLE-A | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class ABLE-A | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class ABLE-A | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class ABLE-A | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class ABLE-A | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class ABLE-F-2 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-1  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-1 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-1 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-1 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-1 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-1 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-2  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-2 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-2 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-2 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-2 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-2 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-2E  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-2E | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-2E | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-2E | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-2E | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-2E | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-3  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-3 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-3 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-3 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-3 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-3 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-4  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-4 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-4 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-4 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-4 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-4 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-5E  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-5E | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-5E | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-5E | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-5E | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-5E | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-5  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-5 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-5 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-5 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-5 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-5 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)
American Funds® U.S. Government Money Market Fund - Class R-6  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
American Funds® U.S. Government Money Market Fund - Class R-6 | US Treasury Bills [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 44.78%
American Funds® U.S. Government Money Market Fund - Class R-6 | Federal Agency Bills And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 37.95%
American Funds® U.S. Government Money Market Fund - Class R-6 | Repurchase Agreements [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.13%
American Funds® U.S. Government Money Market Fund - Class R-6 | US Treasury Bonds And Notes [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.37%
American Funds® U.S. Government Money Market Fund - Class R-6 | Other Assets Less Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.23%)