Shareholder Report, Average Annual Return (Details) 74200174200_Putnam VT Large Cap Growth Fund_Class IA_TSR Annual {Class IA}	12 Months Ended	60 Months Ended	120 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Class IA
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Class IA
Average Annual Return, Percent	14.58%	13.71%	17.95%
Russell 3000 Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Russell 3000 Index
Average Annual Return, Percent	17.15%	13.15%	14.29%
Russell 1000 Growth Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Russell 1000 Growth Index
Average Annual Return, Percent	18.56%	15.32%	18.13%