Investor A1 [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 A1 | BlackRock California Municipal Opportunities Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 2.98% | 3.31% | 5.17% | (8.23%) | 4.61% | 1.37% | 6.34% | 1.16% | 7.13% | 0.32% |