v3.26.1
S000018861 [Member] Average Annual Total Returns
12 Months Ended 60 Months Ended 120 Months Ended 220 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
ICE AMT-Free US National Municipal Index (Spliced) (Returns do not reflect deductions for fees, expenses or taxes)        
Prospectus [Line Items]        
Average Annual Return, Percent [1] 3.90% 0.87% 2.29%  
iShares National Muni Bond ETF        
Prospectus [Line Items]        
Average Annual Return, Percent 3.69% 0.77% 2.13%  
Performance Inception Date       Sep. 07, 2007
iShares National Muni Bond ETF | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 3.68% 0.77% 2.13%  
iShares National Muni Bond ETF | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 3.48% 1.17% 2.20%  
[1] The ICE AMT-Free US National Municipal Index (Spliced) reflects the performance of the S&P National AMT-Free Municipal Bond Index through September 14, 2021 and the ICE AMT-Free US National Municipal Index thereafter, which reflect the times when each index was the Underlying Index of the Fund.