S000003888 [Member] Expense Example, No Redemption - Putnam VT Small Cap Value Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Class IA Shares | |
| Prospectus [Line Items] | |
| Expense Example, No Redemption, 1 Year | $ 79 |
| Expense Example, No Redemption, 3 Years | 246 |
| Expense Example, No Redemption, 5 Years | 428 |
| Expense Example, No Redemption, 10 Years | 955 |
| Class IB Shares | |
| Prospectus [Line Items] | |
| Expense Example, No Redemption, 1 Year | 104 |
| Expense Example, No Redemption, 3 Years | 324 |
| Expense Example, No Redemption, 5 Years | 563 |
| Expense Example, No Redemption, 10 Years | $ 1,247 |