S000001470 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. Aggregate Bond Index (Reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.30% | (0.36%) | 2.01% |
| Bloomberg MBS Index (Reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 8.58% | 0.15% | 1.59% |
| BATS: Mortgage Total Return Series | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 8.66% | 0.48% | 2.02% |
| BATS: Mortgage Total Return Series | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 6.69% | (0.93%) | 0.62% |
| BATS: Mortgage Total Return Series | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.09% | (0.25%) | 0.93% |