S000003883 [Member] Expense Example - Putnam VT Small Cap Growth Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Class IA Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 89 |
| Expense Example, with Redemption, 3 Years | 289 |
| Expense Example, with Redemption, 5 Years | 505 |
| Expense Example, with Redemption, 10 Years | 1,127 |
| Class IB Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 114 |
| Expense Example, with Redemption, 3 Years | 367 |
| Expense Example, with Redemption, 5 Years | 640 |
| Expense Example, with Redemption, 10 Years | $ 1,416 |