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 | BLACKROCK MID CAP GROWTH EQUITY PORTFOLIO | Class K | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 0.49% | 12.55% | 28.34% | (37.29%) | 14.61% | 46.23% | 36.26% | 2.91% | 34.82% | 3.16% |