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S000003882 [Member] Annual Fund Operating Expenses - Putnam VT Government Money Market Fund
Dec. 31, 2025
Class IA Shares  
Prospectus [Line Items]  
Management Fees (as a percentage of Assets) 0.26%
Distribution and Service (12b-1) Fees 0.00%
Other Expenses (as a percentage of Assets): 0.18%
Expenses (as a percentage of Assets) 0.44%
Class IB Shares  
Prospectus [Line Items]  
Management Fees (as a percentage of Assets) 0.26%
Distribution and Service (12b-1) Fees 0.25%
Other Expenses (as a percentage of Assets): 0.18%
Expenses (as a percentage of Assets) 0.69%