v3.26.3
Investor A C and Institutional [Member] Shareholder Fees - Investor A, C and Institutional - BlackRock Short Duration Muni Fund
Jun. 30, 2026
Investor C Shares  
Prospectus [Line Items]  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) 1.00% [1]
Institutional Shares  
Prospectus [Line Items]  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) 0.00%
Investor A Shares  
Prospectus [Line Items]  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 3.00%
Maximum Deferred Sales Charge (as a percentage of Offering Price) 0.00% [2]
[1] There is no CDSC on Investor C Shares after one year.
[2] A contingent deferred sales charge (“CDSC”) of 0.25% is assessed on certain redemptions of Investor A Shares made within 9 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $250,000 or more.