Investor A Institutional [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Investor A Shares Institutional Shares | iShares Russell 1000 Large-Cap Index Fund | Investor A Shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 16.94% | 24.05% | 26.15% | (19.38%) | 25.99% | 20.45% | 30.98% | (5.15%) | 21.16% | 11.61% |