v3.25.4
Shareholder Report, Average Annual Return (Details)
 12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Schwab S&P 500 Index Portfolio      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Schwab S&P 500 Index Portfolio    
Average Annual Return, Percent [1] 17.83% 14.38% 14.75%
Schwab VIT Balanced Portfolio      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Schwab VIT Balanced Portfolio    
Average Annual Return, Percent [2] 12.93% 4.69% 5.51%
Schwab VIT Balanced with Growth Portfolio      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Schwab VIT Balanced with Growth Portfolio    
Average Annual Return, Percent [2] 15.60% 6.45% 7.20%
Schwab VIT Growth Portfolio      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Schwab VIT Growth Portfolio    
Average Annual Return, Percent [2] 18.24% 8.07% 8.65%
Standard & Poor's 500 Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name S&P 500® Index    
Average Annual Return, Percent 17.88% 14.42% 14.82%
Bloomberg US Aggregate Bond Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Bloomberg US Aggregate Bond Index    
Average Annual Return, Percent 7.30% (0.36%) 2.01%
VIT Balanced Composite Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name VIT Balanced Composite Index    
Average Annual Return, Percent 13.32% 5.24% 6.11%
VIT Balanced with Growth Composite Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name VIT Balanced with Growth Composite Index    
Average Annual Return, Percent 16.09% 7.01% 7.79%
VIT Growth Composite Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name VIT Growth Composite Index    
Average Annual Return, Percent 18.73% 8.60% 9.21%
[1] Fund performance does not reflect the additional fees and expenses imposed by the insurance company under the variable insurance product contract. If those contract fees and expenses were included, the performance would be less than that shown. Please refer to the variable insurance product prospectus for a complete listing of these expenses.
[2] Fund expenses may have been partially absorbed by the investment adviser and its affiliates. Without these reductions, the fund’s returns would have been lower. Fund performance does not reflect the additional fees and expenses imposed by the insurance company under the variable insurance product contract. If those contract fees and expenses were included, the performance would be less than that shown. Please refer to the variable insurance product prospectus for a complete listing of these expenses.