S000004360 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended | 281 Months Ended | ||
|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| ICE BofA US Broad Market Index (Returns do not reflect deductions for fees, expenses or taxes) | ||||||
| Prospectus [Line Items] | ||||||
| Average Annual Return, Percent | 7.15% | (0.42%) | 2.01% | |||
| ICE U.S. Treasury 20+ Year Bond Index (Spliced) (Returns do not reflect deductions for fees, expenses or taxes) | ||||||
| Prospectus [Line Items] | ||||||
| Average Annual Return, Percent | [1] | 4.29% | (8.30%) | (0.46%) | ||
| iShares 20+ Year Treasury Bond ETF | ||||||
| Prospectus [Line Items] | ||||||
| Average Annual Return, Percent | 4.17% | (8.37%) | (0.55%) | |||
| Performance Inception Date | Jul. 22, 2002 | |||||
| iShares 20+ Year Treasury Bond ETF | After Taxes on Distributions | ||||||
| Prospectus [Line Items] | ||||||
| Average Annual Return, Percent | 2.34% | (9.53%) | (1.65%) | |||
| iShares 20+ Year Treasury Bond ETF | After Taxes on Distributions and Sales | ||||||
| Prospectus [Line Items] | ||||||
| Average Annual Return, Percent | 2.46% | (6.50%) | (0.82%) | |||
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