v3.26.1
S000003894 [Member] Expense Example - Putnam VT Large Cap Value Fund
Dec. 31, 2025
USD ($)
Class IA Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 55
Expense Example, with Redemption, 3 Years 173
Expense Example, with Redemption, 5 Years 302
Expense Example, with Redemption, 10 Years 678
Class IB Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 81
Expense Example, with Redemption, 3 Years 253
Expense Example, with Redemption, 5 Years 439
Expense Example, with Redemption, 10 Years $ 978