Putnam Variable Trust N-CSRS29 Aug 24Certified semi-annual shareholder report (management investment company)Financial data

Company Profile

Form N-CSR Cover

Form N-CSR Cover	6 Months Ended
Form N-CSR Cover	Jun. 30, 2024
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Putnam Variable Trust
Entity Central Index Key	0000822671
Entity Investment Company Type	N-1A
Document Period End Date	Jun. 30, 2024

Shareholder Report

Shareholder Report	6 Months Ended
Shareholder Report	Jun. 30, 2024 USD ($) $ / shares
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Putnam Variable Trust
Entity Central Index Key	0000822671
Entity Investment Company Type	N-1A
Document Period End Date	Jun. 30, 2024
Class IA
Shareholder Report [Line Items]
Fund Name	Putnam VT International Equity Fund
Class Name	Class IA
No Trading Symbol Flag	true
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains important information about Putnam VT International Equity Fund for the period January 1, 2024, to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents . You can also request this information by contacting us at (800) 225-1581 .
Additional Information Phone Number	(800) 225-1581
Additional Information Website	https://www.franklintempleton.com/regulatory-fund-documents.
Expenses [Text Block]	WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment † Class IA 1 $42 0.83%	[1],[2]
Expenses Paid, Amount	$ 42	[1]
Expense Ratio, Percent	0.83%	[1]
Net Assets	$ 225,262,543
Holdings Count \| $ / shares	171	[3]
Investment Company Portfolio Turnover	43%
Additional Fund Statistics [Text Block]	KEY FUND STATISTICS (as of June 30, 2024) Total Net Assets $225,262,543 Total Number of Portfolio Holdings * 171 Portfolio Turnover Rate 43%	[3]
Holdings [Text Block]		[4]
Updated Prospectus Web Address	https://www.franklintempleton.com/regulatory-fund-documents
Class IB
Shareholder Report [Line Items]
Fund Name	Putnam VT International Equity Fund
Class Name	Class IB
No Trading Symbol Flag	true
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains important information about Putnam VT International Equity Fund for the period January 1, 2024, to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents . You can also request this information by contacting us at (800) 225-1581 .
Additional Information Phone Number	(800) 225-1581
Additional Information Website	https://www.franklintempleton.com/regulatory-fund-documents.
Expenses [Text Block]	WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment † Class IB 1 $55 1.08%	[5],[6]
Expenses Paid, Amount	$ 55	[5]
Expense Ratio, Percent	1.08%	[5]
Net Assets	$ 225,262,543
Holdings Count \| $ / shares	171	[7]
Investment Company Portfolio Turnover	43%
Additional Fund Statistics [Text Block]	KEY FUND STATISTICS (as of June 30, 2024) Total Net Assets $225,262,543 Total Number of Portfolio Holdings * 171 Portfolio Turnover Rate 43%	[7]
Holdings [Text Block]		[8]
Updated Prospectus Web Address	https://www.franklintempleton.com/regulatory-fund-documents

[1] 1 Does not reflect expenses incurred from investing through variable annuity or variable life insurance products. † Annualized. * Includes derivatives, if applicable. Cash and Equivalents, if any, represent the market value weights of cash, derivatives, short-term securities, and other unclassified assets in the portfolio. Holdings and allocations may vary over time. 1 Does not reflect expenses incurred from investing through variable annuity or variable life insurance products. † Annualized. * Includes derivatives, if applicable. Cash and Equivalents, if any, represent the market value weights of cash, derivatives, short-term securities, and other unclassified assets in the portfolio. Holdings and allocations may vary over time.

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Jun. 30, 2024
Class IA \| Cash and Equivalent [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Class IA \| Japan
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Class IA \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	19.30%
Class IA \| France
Holdings [Line Items]
Percent of Net Asset Value	10.10%
Class IA \| Netherlands
Holdings [Line Items]
Percent of Net Asset Value	6.20%
Class IA \| United States
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Class IA \| Germany
Holdings [Line Items]
Percent of Net Asset Value	5%
Class IA \| South Korea
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Class IA \| Switzerland
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Class IA \| Ireland
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IA \| Taiwan
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IA \| Canada
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IA \| Hong Kong
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Class IA \| Italy
Holdings [Line Items]
Percent of Net Asset Value	2.60%
Class IA \| Denmark
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Class IA \| Australia
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Class IA \| Spain
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Class IB \| Cash and Equivalent [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Class IB \| Japan
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Class IB \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	19.30%
Class IB \| France
Holdings [Line Items]
Percent of Net Asset Value	10.10%
Class IB \| Netherlands
Holdings [Line Items]
Percent of Net Asset Value	6.20%
Class IB \| United States
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Class IB \| Germany
Holdings [Line Items]
Percent of Net Asset Value	5%
Class IB \| South Korea
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Class IB \| Switzerland
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Class IB \| Ireland
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IB \| Taiwan
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IB \| Canada
Holdings [Line Items]
Percent of Net Asset Value	3.40%
Class IB \| Hong Kong
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Class IB \| Italy
Holdings [Line Items]
Percent of Net Asset Value	2.60%
Class IB \| Denmark
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Class IB \| Australia
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Class IB \| Spain
Holdings [Line Items]
Percent of Net Asset Value	1.50%