Investor A C and Institutional [Member] Expense Example, No Redemption - Investor A, C and Institutional - BlackRock National Municipal Fund - Investor C Shares |
Jun. 30, 2026
USD ($)
|
|---|---|
| Prospectus [Line Items] | |
| Expense Example, No Redemption, 1 Year | $ 153 |
| Expense Example, No Redemption, 3 Years | 487 |
| Expense Example, No Redemption, 5 Years | 844 |
| Expense Example, No Redemption, 10 Years | $ 1,647 |