S000006018 [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 |
|
| Versatile Bond Portfolio | Class I | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 5.66% | 5.78% | 6.91% | (5.92%) | 2.93% | 9.87% | 9.29% | 2.02% | 0.71% | 14.44% |