v3.26.1
S000003880 [Member] Expense Example - Putnam VT Core Equity Fund
Dec. 31, 2025
USD ($)
Class IA Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 68
Expense Example, with Redemption, 3 Years 214
Expense Example, with Redemption, 5 Years 373
Expense Example, with Redemption, 10 Years 834
Class IB Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 94
Expense Example, with Redemption, 3 Years 294
Expense Example, with Redemption, 5 Years 510
Expense Example, with Redemption, 10 Years $ 1,132