v3.26.1
S000003876 [Member] Expense Example - Putnam VT Income Fund
Dec. 31, 2025
USD ($)
Class IA Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 58
Expense Example, with Redemption, 3 Years 183
Expense Example, with Redemption, 5 Years 318
Expense Example, with Redemption, 10 Years 713
Class IB Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 84
Expense Example, with Redemption, 3 Years 262
Expense Example, with Redemption, 5 Years 456
Expense Example, with Redemption, 10 Years $ 1,015