S000001587 [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 |
|
| Investment Grade Bond Fund | Class S | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 7.27% | 1.42% | 5.02% | (14.92%) | (1.25%) | 8.95% | 8.88% | (0.76%) | 3.47% | 2.50% |