Investor A Institutional [Member] Expense Example - Investor A Shares Institutional Shares - iShares Russell 1000 Large-Cap Index Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Investor A Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 37 |
| Expense Example, with Redemption, 3 Years | 116 |
| Expense Example, with Redemption, 5 Years | 202 |
| Expense Example, with Redemption, 10 Years | 456 |
| Institutional Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 11 |
| Expense Example, with Redemption, 3 Years | 35 |
| Expense Example, with Redemption, 5 Years | 62 |
| Expense Example, with Redemption, 10 Years | $ 141 |