Class K [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 |
|
| Class K | iShares Russell 1000 Large-Cap Index Fund | Class K shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 17.27% | 24.44% | 26.48% | (19.12%) | 26.37% | 20.84% | 31.28% | (4.85%) | 21.60% | 11.92% |