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S000003893 [Member] Annual Fund Operating Expenses - Putnam VT Diversified Income Fund
Dec. 31, 2025
Class IA Shares  
Prospectus [Line Items]  
Management Fees (as a percentage of Assets) 0.52%
Distribution and Service (12b-1) Fees 0.00%
Other Expenses (as a percentage of Assets): 0.27%
Acquired Fund Fees and Expenses 0.01%
Expenses (as a percentage of Assets) 0.80% [1]
Class IB Shares  
Prospectus [Line Items]  
Management Fees (as a percentage of Assets) 0.52%
Distribution and Service (12b-1) Fees 0.25%
Other Expenses (as a percentage of Assets): 0.27%
Acquired Fund Fees and Expenses 0.01%
Expenses (as a percentage of Assets) 1.05% [1]
[1] Total annual fund operating expenses do not correlate with the ratios of expenses to average net assets reported in the fund’s financial highlights, which reflect the fund’s operating expenses and do not include acquired fund fees and expenses.