S000052179 [Member] Annual Total Returns |
12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
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 |
|
| Western Asset SMASh Series TF Fund | Western Asset SMASh Series TF Fund | |||||||||
| Prospectus [Line Items] | |||||||||
| Annual Return [Percent] | 2.23% | 7.96% | (9.84%) | 3.81% | 4.69% | 8.16% | 0.71% | 7.02% | 0.33% |