v3.26.3
Expense Example, No Redemption - AMERICAN HIGH-INCOME MUNICIPAL BOND FUND (Class A, Class C, Class F-1, Class F-2, Class F-3) - AMERICAN HIGH-INCOME MUNICIPAL BOND FUND - Class C
Sep. 30, 2026
USD ($)
Prospectus [Line Items]  
Expense Example, No Redemption, 1 Year $ 139
Expense Example, No Redemption, 3 Years 434
Expense Example, No Redemption, 5 Years 750
Expense Example, No Redemption, 10 Years $ 1,454