v3.26.1
State Street Income VIS Fund 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 Bond Index (reflects no deduction for fees, expenses or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 7.30% (0.36%) 2.01%
Class 1      
Prospectus [Line Items]      
Average Annual Return, Percent 5.91% (1.56%) 1.20%