v3.25.4
Shareholder Report, Line Graph (Details) - USD ($)
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2015
Dec. 31, 2025
Dec. 31, 2016
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2019
Dec. 31, 2020
Dec. 31, 2021
Dec. 31, 2022
Dec. 31, 2023
Dec. 31, 2024
Dec. 31, 2025
Schwab S&P 500 Index Portfolio                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Schwab S&P 500 Index Portfolio                    
Accumulated Value [1] $ 10,000   $ 11,167.89 $ 13,593.97 $ 12,995.4 $ 17,086.47 $ 20,209.56 $ 26,004.07 $ 21,293.39 $ 26,877.11 $ 33,583.78 $ 39,570.64
Schwab VIT Balanced Portfolio                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Schwab VIT Balanced Portfolio                    
Accumulated Value [2] 10,000   10,477.96 11,526.08 10,991.89 12,557.56 13,590.81 14,703.6 12,540.76 14,040.71 15,143.85 17,090.16
Schwab VIT Balanced with Growth Portfolio                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Schwab VIT Balanced with Growth Portfolio                    
Accumulated Value [2] 10,000   10,637.55 12,094.57 11,283.96 13,320.53 14,664.24 16,339.26 13,724.3 15,763.01 17,336.1 20,039.85
Schwab VIT Growth Portfolio                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Schwab VIT Growth Portfolio                    
Accumulated Value [2] 10,000   10,766.58 12,611.76 11,558.19 13,967.2 15,550.72 17,831.77 14,757.36 17,343.26 19,385.61 22,921.24
Standard & Poor's 500 Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   S&P 500® Index                    
Accumulated Value 10,000   11,195.99 13,640.25 13,042.22 17,148.74 20,303.9 26,132.22 21,399.45 27,024.86 33,786.4 39,827.41
Bloomberg US Aggregate Bond Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   Bloomberg US Aggregate Bond Index                    
Accumulated Value 10,000   10,264.75 10,628.31 10,629.52 11,556.06 12,423.53 12,231.95 10,640.56 11,228.86 11,369.25 12,199.31
VIT Balanced Composite Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   VIT Balanced Composite Index                    
Accumulated Value 10,000   10,569.37 11,682.6 11,199.21 12,878.03 14,019.05 15,251.03 13,093.68 14,723.79 15,969.79 18,096.33
VIT Balanced with Growth Composite Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   VIT Balanced with Growth Composite Index                    
Accumulated Value 10,000   10,715.64 12,226.52 11,474.17 13,620.58 15,082.08 16,906.26 14,281.9 16,478.21 18,231.83 21,164.5
VIT Growth Composite Index [Member]                        
Account Value [Line Items]                        
Line Graph and Table Measure Name   VIT Growth Composite Index                    
Accumulated Value $ 10,000   $ 10,839.58 $ 12,743.23 $ 11,731.02 $ 14,274.13 $ 15,980.06 $ 18,427.35 $ 15,323.38 $ 18,075.03 $ 20,335.51 $ 24,143.4
[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.