Investor A C and Institutional [Member] Expense Example - Investor A, C and Institutional - BlackRock Short Duration Muni Fund |
Jun. 30, 2026
USD ($)
|
|---|---|
| Investor C Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 239 |
| Expense Example, with Redemption, 3 Years | 453 |
| Expense Example, with Redemption, 5 Years | 789 |
| Expense Example, with Redemption, 10 Years | 1,521 |
| Institutional Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 38 |
| Expense Example, with Redemption, 3 Years | 143 |
| Expense Example, with Redemption, 5 Years | 258 |
| Expense Example, with Redemption, 10 Years | 593 |
| Investor A Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 360 |
| Expense Example, with Redemption, 3 Years | 500 |
| Expense Example, with Redemption, 5 Years | 652 |
| Expense Example, with Redemption, 10 Years | $ 1,093 |