S000003881 [Member] Expense Example - Putnam VT Sustainable Future Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Class IA Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 82 |
| Expense Example, with Redemption, 3 Years | 273 |
| Expense Example, with Redemption, 5 Years | 480 |
| Expense Example, with Redemption, 10 Years | 1,077 |
| Class IB Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 107 |
| Expense Example, with Redemption, 3 Years | 351 |
| Expense Example, with Redemption, 5 Years | 614 |
| Expense Example, with Redemption, 10 Years | $ 1,366 |