State Street Emerging Markets Enhanced Index Portfolio Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 80 Months Ended | |
|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| MSCI Emerging Markets Index (reflects no deduction for mutual fund fees or expenses)[Member] | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 33.57% | 4.20% | 6.63% | |
| Class A | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 34.45% | 6.31% | 7.49% | |
| Performance Inception Date | Apr. 29, 2019 | |||
| Class B | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 34.14% | 6.04% | 7.23% | |
| Performance Inception Date | Apr. 29, 2019 |