This semi-annual shareholder report contains important information about the Eaton Vance VT Floating-Rate Income Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.eatonvance.com/variable-portfolios.php. You can also request this information by contacting us at 1-800-262-1122.

Additional Information Phone Number

1-800-262-1122

Additional Information Website

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Expenses [Text Block]

What were the Fund costs for the last six months?^{Footnote Reference1}

(based on a hypothetical $10,000 investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
ADV Class	$48	0.97%^{Footnote Reference2}

Footnote	Description
Footnote¹	Does not reflect expenses and charges that are, or may be, imposed under the variable annuity contract or variable life insurance separate account or qualified pension or retirement plan through which your investment in the Fund is made.
Footnote²	Annualized

Expenses Paid, Amount

$ 48

Expense Ratio, Percent

0.97%

^[1]

Expenses Represent Both Master and Feeder [Text]

Does not reflect expenses and charges that are, or may be, imposed under the variable annuity contract or variable life insurance separate account or qualified pension or retirement plan through which your investment in the Fund is made.

AssetsNet

$ 495,386,818

Holdings Count | Holding

479

InvestmentCompanyPortfolioTurnover

26.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$495,386,818
# of Portfolio Holdings	479
Portfolio Turnover Rate	26%

Holdings [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Other^{Footnote Reference*}	0.1%
Exchange-Traded Funds	1.0%
Common Stocks	1.1%
Asset-Backed Securities	3.0%
Corporate Bonds	4.0%
Short-Term Investments	6.4%
Senior Floating-Rate Loans	84.4%

Footnote	Description
Footnote^*	Investment types less than 1% each

Credit Quality (% of net assets)^{Footnote Referencea}

Table Summary
Value	Value
Not Rated	1.1%
CCC or Lower	2.8%
B	66.8%
BB	20.6%
BBB	3.3%

Footnote	Description
Footnote^a	Excludes Equities, ETFs and Cash and Cash Equivalents. Ratings are categorized using S&P Global Ratings (“S&P”), with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by S&P.

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-800-262-1122

C000014195

Shareholder Report [Line Items]

Fund Name

Eaton Vance VT Floating-Rate Income Fund

Class Name

Initial Class

Trading Symbol

VTFLR

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Eaton Vance VT Floating-Rate Income Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.eatonvance.com/variable-portfolios.php. You can also request this information by contacting us at 1-800-262-1122.

Additional Information Phone Number

1-800-262-1122

Additional Information Website

Expenses [Text Block]

What were the Fund costs for the last six months?^{Footnote Reference1}

(based on a hypothetical $10,000 investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Initial Class	$61	1.22%^{Footnote Reference2}

Footnote	Description
Footnote¹	Does not reflect expenses and charges that are, or may be, imposed under the variable annuity contract or variable life insurance separate account or qualified pension or retirement plan through which your investment in the Fund is made.
Footnote²	Annualized

Expenses Paid, Amount

$ 61

Expense Ratio, Percent

1.22%

^[2]

Expenses Represent Both Master and Feeder [Text]

AssetsNet

$ 495,386,818

Holdings Count | Holding

479

InvestmentCompanyPortfolioTurnover

26.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$495,386,818
# of Portfolio Holdings	479
Portfolio Turnover Rate	26%

Holdings [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Other^{Footnote Reference*}	0.1%
Exchange-Traded Funds	1.0%
Common Stocks	1.1%
Asset-Backed Securities	3.0%
Corporate Bonds	4.0%
Short-Term Investments	6.4%
Senior Floating-Rate Loans	84.4%

Footnote	Description
Footnote^*	Investment types less than 1% each

Credit Quality (% of net assets)^{Footnote Referencea}

Table Summary
Value	Value
Not Rated	1.1%
CCC or Lower	2.8%
B	66.8%
BB	20.6%
BBB	3.3%

Footnote	Description
Footnote^a	Excludes Equities, ETFs and Cash and Cash Equivalents. Ratings are categorized using S&P Global Ratings (“S&P”), with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by S&P.

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-800-262-1122

C000162648

Shareholder Report [Line Items]

Fund Name

Eaton Vance VT Floating-Rate Income Fund

Class Name

Institutional Class

Trading Symbol

VTFLI

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Eaton Vance VT Floating-Rate Income Fund for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Fund at www.eatonvance.com/variable-portfolios.php. You can also request this information by contacting us at 1-800-262-1122.

Additional Information Phone Number

1-800-262-1122

Additional Information Website

Expenses [Text Block]

What were the Fund costs for the last six months?^{Footnote Reference1}

(based on a hypothetical $10,000 investment)

Table Summary
Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$35	0.71%^{Footnote Reference2}

Footnote	Description
Footnote¹	Does not reflect expenses and charges that are, or may be, imposed under the variable annuity contract or variable life insurance separate account or qualified pension or retirement plan through which your investment in the Fund is made.
Footnote²	Annualized

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.71%

^[3]

Expenses Represent Both Master and Feeder [Text]

AssetsNet

$ 495,386,818

Holdings Count | Holding

479

InvestmentCompanyPortfolioTurnover

26.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Total Net Assets	$495,386,818
# of Portfolio Holdings	479
Portfolio Turnover Rate	26%

Holdings [Text Block]

Asset Allocation (% of total investments)

Table Summary
Value	Value
Other^{Footnote Reference*}	0.1%
Exchange-Traded Funds	1.0%
Common Stocks	1.1%
Asset-Backed Securities	3.0%
Corporate Bonds	4.0%
Short-Term Investments	6.4%
Senior Floating-Rate Loans	84.4%

Footnote	Description
Footnote^*	Investment types less than 1% each

Credit Quality (% of net assets)^{Footnote Referencea}

Table Summary
Value	Value
Not Rated	1.1%
CCC or Lower	2.8%
B	66.8%
BB	20.6%
BBB	3.3%

Footnote	Description
Footnote^a	Excludes Equities, ETFs and Cash and Cash Equivalents. Ratings are categorized using S&P Global Ratings (“S&P”), with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by S&P.

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-800-262-1122

[1]	Annualized
[2]	Annualized
[3]	Annualized

What were the Fund costs for the last six months?Footnote Reference1

Key Fund Statistics

Asset Allocation (% of total investments)

Credit Quality (% of net assets)Footnote Referencea

What were the Fund costs for the last six months?Footnote Reference1

Key Fund Statistics

Asset Allocation (% of total investments)

Credit Quality (% of net assets)Footnote Referencea

What were the Fund costs for the last six months?Footnote Reference1

Key Fund Statistics

Asset Allocation (% of total investments)

Credit Quality (% of net assets)Footnote Referencea

What were the Fund costs for the last six months?^{Footnote Reference1}

Credit Quality (% of net assets)^{Footnote Referencea}

What were the Fund costs for the last six months?^{Footnote Reference1}

Credit Quality (% of net assets)^{Footnote Referencea}

What were the Fund costs for the last six months?^{Footnote Reference1}

Credit Quality (% of net assets)^{Footnote Referencea}