S000002682 [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 |
|
| UBS Select Treasury Institutional Fund | UBS Select Treasury Institutional Fund | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 4.11% | 5.09% | 4.95% | 1.49% | 0.01% | 0.37% | 2.06% | 1.70% | 0.72% | 0.18% |