v3.25.2
Investor A C and Institutional [Member] Expense Example - Investor A, C and Institutional - BlackRock Strategic Municipal Opportunities Fund
May 31, 2025
USD ($)
Investor A Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 519
Expense Example, with Redemption, 3 Years 728
Expense Example, with Redemption, 5 Years 954
Expense Example, with Redemption, 10 Years 1,604
Investor C Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 276
Expense Example, with Redemption, 3 Years 557
Expense Example, with Redemption, 5 Years 964
Expense Example, with Redemption, 10 Years 1,895
Institutional Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 78
Expense Example, with Redemption, 3 Years 254
Expense Example, with Redemption, 5 Years 445
Expense Example, with Redemption, 10 Years $ 997