S000014681 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. Aggregate Index (reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.30% | (0.36%) | 2.01% |
| Bloomberg U.S. MBS: Agency Fixed Rate Index (reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 8.58% | 0.15% | 1.59% |
| SMASh Series M Fund | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 12.31% | (3.02%) | 1.62% |
| SMASh Series M Fund | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 10.30% | (4.59%) | (0.11%) |
| SMASh Series M Fund | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 7.24% | (2.92%) | 0.61% |