S000003870 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| BlackRock Government Money Market Portfolio | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 3.90% | 2.91% | 1.84% |