Investor P Shares [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 P | iShares Russell 2000 Small-Cap Index Fund | Investor P Shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 12.47% | 11.14% | 16.62% | (20.57%) | 14.42% | 19.65% | 25.25% | (11.19%) | 14.27% | 21.03% |