Fees and Expenses - Putnam VT Sustainable Leaders Fund	Jun. 30, 2026
Prospectus [Line Items]
Expense Heading [Optional Text]	Fees and expenses
Expense Narrative [Text Block]	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. The fees and expenses information does not reflect insurance-related charges or expenses borne by contract holders indirectly investing in the fund. If it did, expenses would be higher.
Operating Expenses Caption [Optional Text]	Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)
Expense Example [Heading]	Example
Expense Example Narrative [Text Block]	The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. The example does not reflect insurance-related charges or expenses. If it did, expenses would be higher. It assumes that you invest $10,000 in the fund for the time periods indicated and then redeem or hold all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same (except that any applicable fee waiver or expense reimbursement is reflected only through its expiration date). Your actual costs may be higher or lower.
Portfolio Turnover [Heading]	Portfolio turnover
Portfolio Turnover [Text Block]	The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 43%.
Portfolio Turnover, Rate	43.00%

Fees and Expenses - Putnam VT Sustainable Leaders Fund

Jun. 30, 2026

Fees and expenses

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. The fees and expenses information does not reflect insurance-related charges or expenses borne by contract holders indirectly investing in the fund. If it did, expenses would be higher.

Operating Expenses Caption [Optional Text]

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)

Expense Example [Heading]

Example

Expense Example Narrative [Text Block]

The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. The example does not reflect insurance-related charges or expenses. If it did, expenses would be higher. It assumes that you invest $10,000 in the fund for the time periods indicated and then redeem or hold all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same (except that any applicable fee waiver or expense reimbursement is reflected only through its expiration date). Your actual costs may be higher or lower.

Portfolio Turnover [Heading]

Portfolio turnover

Portfolio Turnover [Text Block]

The fund pays transaction-related costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher turnover rate may indicate higher transaction costs. These costs, which are not reflected in

annual fund operating expenses or the above example, affect fund performance. The fund’s turnover rate in the most recent fiscal year was 43%.

Portfolio Turnover, Rate

43.00%