S000001471 [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: Short Duration Taxable Total Return Series | BATS: Short Duration Taxable Total Return Series | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 6.06% | 5.51% | 6.03% | (4.11%) | 0.13% | 3.88% | 6.24% | 1.41% | 2.48% | 3.09% |