v3.26.1
S000003878 [Member] Expense Example - Putnam VT International Value Fund
Dec. 31, 2025
USD ($)
Class IA Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 83
Expense Example, with Redemption, 3 Years 259
Expense Example, with Redemption, 5 Years 450
Expense Example, with Redemption, 10 Years 1,003
Class IB Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 108
Expense Example, with Redemption, 3 Years 337
Expense Example, with Redemption, 5 Years 584
Expense Example, with Redemption, 10 Years $ 1,293