Service Shares [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
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 |
Dec. 31, 2015 |
|
| Service Shares [Member] | BLACKROCK HEALTH SCIENCES OPPORTUNITIES PORTFOLIO | SERVICE | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 3.78% | 3.53% | (5.96%) | 11.74% | 19.43% | 25.25% | 7.95% | 24.79% | (6.05%) | 11.00% |