S000011985 [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 |
|
| BATS: Interest Rate Hedge Series | BATS: Interest Rate Hedge Series | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 0.18% | 14.27% | 4.27% | 19.73% | 2.94% | (7.48%) | (4.82%) | 1.72% | (0.19%) | 0.32% |