NORTHERN ULTRASHORT FIXED INCOME FUND [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 |
|
| NORTHERN ULTRASHORT FIXED INCOME FUND | ULTRA-SHORT FIXED INCOME FUND | ULTRA-SHORT FIXED INCOME FUND | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 5.16% | 5.94% | 6.29% | (1.01%) | (0.05%) | 2.34% | 3.67% | 1.54% | 1.52% | 1.52% |