v3.26.3
Investor A C and Institutional [Member] Expense Example - Investor A C and Institutional - BlackRock Strategic Municipal Opportunities Fund of BlackRock Municipal Series Trust
May 31, 2026
USD ($)
Institutional Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 94
Expense Example, with Redemption, 3 Years 304
Expense Example, with Redemption, 5 Years 531
Expense Example, with Redemption, 10 Years 1,185
Investor A Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 534
Expense Example, with Redemption, 3 Years 778
Expense Example, with Redemption, 5 Years 1,041
Expense Example, with Redemption, 10 Years 1,791
Investor C Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 294
Expense Example, with Redemption, 3 Years 610
Expense Example, with Redemption, 5 Years 1,053
Expense Example, with Redemption, 10 Years $ 2,079