This semi-annual shareholder report contains important information about the Baillie Gifford International Stock Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 18px; margin: 0px; overflow: visible; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">https://dfinview.com/BHFT

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$38	0.74%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.74%

^[1]

AssetsNet

$ 1,293,148,665

Holdings Count | Holding

100

Advisory Fees Paid, Amount

$ 4,581,185

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,293,148,665
# of Portfolio Investments100
Portfolio Turnover Rate20%
Total Advisory Fees Paid$4,581,185

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Energy	2.0
Health Care	4.3
Consumer Staples	4.8
Communication Services	6.6
Consumer Discretionary	7.9
Materials	8.6
Industrials	15.4
Financials	21.3
Information Technology	27.8

Top 10 Countries

Table Summary
Value	Value
Italy	4.1
Brazil	4.5
France	4.6
United States	5.0
Netherlands	5.7
Germany	6.4
South Korea	6.5
China	9.7
Taiwan	10.4
Japan	12.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.	7.8
Samsung Electronics Co. Ltd.	6.5
Tencent Holdings Ltd.	2.8
ASML Holding NV	2.6
MediaTek, Inc.	2.6
Rio Tinto PLC	2.5
Deutsche Boerse AG	2.2
Roche Holding AG	2.1
DSV AS	2.0
Discovery Ltd.	1.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: justify; text-align-last: left; white-space-collapse: preserve-breaks;">https://dfinview.com/BHFT

C000017776

Shareholder Report [Line Items]

Fund Name

Baillie Gifford International Stock Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Baillie Gifford International Stock Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$51	0.99%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 51

Expense Ratio, Percent

0.99%

^[2]

AssetsNet

$ 1,293,148,665

Holdings Count | Holding

100

Advisory Fees Paid, Amount

$ 4,581,185

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,293,148,665
# of Portfolio Investments100
Portfolio Turnover Rate20%
Total Advisory Fees Paid$4,581,185

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Energy	2.0
Health Care	4.3
Consumer Staples	4.8
Communication Services	6.6
Consumer Discretionary	7.9
Materials	8.6
Industrials	15.4
Financials	21.3
Information Technology	27.8

Top 10 Countries

Table Summary
Value	Value
Italy	4.1
Brazil	4.5
France	4.6
United States	5.0
Netherlands	5.7
Germany	6.4
South Korea	6.5
China	9.7
Taiwan	10.4
Japan	12.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.	7.8
Samsung Electronics Co. Ltd.	6.5
Tencent Holdings Ltd.	2.8
ASML Holding NV	2.6
MediaTek, Inc.	2.6
Rio Tinto PLC	2.5
Deutsche Boerse AG	2.2
Roche Holding AG	2.1
DSV AS	2.0
Discovery Ltd.	1.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017777

Shareholder Report [Line Items]

Fund Name

Baillie Gifford International Stock Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Baillie Gifford International Stock Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$46	0.89%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 46

Expense Ratio, Percent

0.89%

^[3]

AssetsNet

$ 1,293,148,665

Holdings Count | Holding

100

Advisory Fees Paid, Amount

$ 4,581,185

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,293,148,665
# of Portfolio Investments100
Portfolio Turnover Rate20%
Total Advisory Fees Paid$4,581,185

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Energy	2.0
Health Care	4.3
Consumer Staples	4.8
Communication Services	6.6
Consumer Discretionary	7.9
Materials	8.6
Industrials	15.4
Financials	21.3
Information Technology	27.8

Top 10 Countries

Table Summary
Value	Value
Italy	4.1
Brazil	4.5
France	4.6
United States	5.0
Netherlands	5.7
Germany	6.4
South Korea	6.5
China	9.7
Taiwan	10.4
Japan	12.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Taiwan Semiconductor Manufacturing Co. Ltd.	7.8
Samsung Electronics Co. Ltd.	6.5
Tencent Holdings Ltd.	2.8
ASML Holding NV	2.6
MediaTek, Inc.	2.6
Rio Tinto PLC	2.5
Deutsche Boerse AG	2.2
Roche Holding AG	2.1
DSV AS	2.0
Discovery Ltd.	1.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017802

Shareholder Report [Line Items]

Fund Name

BlackRock Bond Income Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Bond Income Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$19	0.38%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 19

Expense Ratio, Percent

0.38%

^[4]

AssetsNet

$ 2,488,743,586

Holdings Count | Holding

4,257

Advisory Fees Paid, Amount

$ 4,272,481

InvestmentCompanyPortfolioTurnover

203.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,488,743,586
# of Portfolio Investments4,257
Portfolio Turnover Rate203%
Total Advisory Fees Paid$4,272,481

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.1
Preferred Stocks	0.3
Common Stocks	0.3
Municipals	0.6
Floating Rate Loans	1.0
Short-Term Investments	2.4
Foreign Government	3.7
Asset-Backed Securities	13.4
Non-Agency Mortgage-Backed Securities	14.5
U.S. Treasury & Government Agencies	21.2
Corporate Bonds & Notes	21.3
Agency Sponsored Mortgage-Backed Securities	32.2

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	13.3
Federal National Mortgage Association	9.6
Uniform Mortgage-Backed Security, TBA	8.4
U.S. Treasury Bonds	7.9
Federal Home Loan Mortgage Corp.	6.7
Government National Mortgage Association	2.9
Government National Mortgage Association, TBA	2.9
EQT Corp.	1.6
Federal Home Loan Mortgage Corp. REMICS	1.2
Diamondback Energy, Inc.	1.1

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017803

Shareholder Report [Line Items]

Fund Name

BlackRock Bond Income Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Bond Income Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$31	0.63%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 31

Expense Ratio, Percent

0.63%

^[5]

AssetsNet

$ 2,488,743,586

Holdings Count | Holding

4,257

Advisory Fees Paid, Amount

$ 4,272,481

InvestmentCompanyPortfolioTurnover

203.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,488,743,586
# of Portfolio Investments4,257
Portfolio Turnover Rate203%
Total Advisory Fees Paid$4,272,481

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.1
Preferred Stocks	0.3
Common Stocks	0.3
Municipals	0.6
Floating Rate Loans	1.0
Short-Term Investments	2.4
Foreign Government	3.7
Asset-Backed Securities	13.4
Non-Agency Mortgage-Backed Securities	14.5
U.S. Treasury & Government Agencies	21.2
Corporate Bonds & Notes	21.3
Agency Sponsored Mortgage-Backed Securities	32.2

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	13.3
Federal National Mortgage Association	9.6
Uniform Mortgage-Backed Security, TBA	8.4
U.S. Treasury Bonds	7.9
Federal Home Loan Mortgage Corp.	6.7
Government National Mortgage Association	2.9
Government National Mortgage Association, TBA	2.9
EQT Corp.	1.6
Federal Home Loan Mortgage Corp. REMICS	1.2
Diamondback Energy, Inc.	1.1

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017804

Shareholder Report [Line Items]

Fund Name

BlackRock Bond Income Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Bond Income Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$26	0.53%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.53%

^[6]

AssetsNet

$ 2,488,743,586

Holdings Count | Holding

4,257

Advisory Fees Paid, Amount

$ 4,272,481

InvestmentCompanyPortfolioTurnover

203.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,488,743,586
# of Portfolio Investments4,257
Portfolio Turnover Rate203%
Total Advisory Fees Paid$4,272,481

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.1
Preferred Stocks	0.3
Common Stocks	0.3
Municipals	0.6
Floating Rate Loans	1.0
Short-Term Investments	2.4
Foreign Government	3.7
Asset-Backed Securities	13.4
Non-Agency Mortgage-Backed Securities	14.5
U.S. Treasury & Government Agencies	21.2
Corporate Bonds & Notes	21.3
Agency Sponsored Mortgage-Backed Securities	32.2

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	13.3
Federal National Mortgage Association	9.6
Uniform Mortgage-Backed Security, TBA	8.4
U.S. Treasury Bonds	7.9
Federal Home Loan Mortgage Corp.	6.7
Government National Mortgage Association	2.9
Government National Mortgage Association, TBA	2.9
EQT Corp.	1.6
Federal Home Loan Mortgage Corp. REMICS	1.2
Diamondback Energy, Inc.	1.1

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017861

Shareholder Report [Line Items]

Fund Name

BlackRock Capital Appreciation Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Capital Appreciation Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$30	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.56%

^[7]

AssetsNet

$ 1,962,769,931

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 4,782,765

InvestmentCompanyPortfolioTurnover

52.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,962,769,931
# of Portfolio Investments48
Portfolio Turnover Rate52%
Total Advisory Fees Paid$4,782,765

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.8
Materials	1.8
Energy	2.5
Health Care	3.1
Real Estate	4.1
Consumer Discretionary	8.1
Communication Services	11.0
Industrials	14.9
Information Technology	53.5

Top Countries

Table Summary
Value	Value
China	0.8
Brazil	1.8
United States	97.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.1
Amazon.com, Inc.	7.2
Apple, Inc.	5.4
Alphabet, Inc.	4.9
Microsoft Corp.	4.9
Broadcom, Inc.	4.6
Databricks, Inc.	3.5
Meta Platforms, Inc.	3.5
Palo Alto Networks, Inc.	3.3
Caterpillar, Inc.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017862

Shareholder Report [Line Items]

Fund Name

BlackRock Capital Appreciation Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Capital Appreciation Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$43	0.81%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 43

Expense Ratio, Percent

0.81%

^[8]

AssetsNet

$ 1,962,769,931

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 4,782,765

InvestmentCompanyPortfolioTurnover

52.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,962,769,931
# of Portfolio Investments48
Portfolio Turnover Rate52%
Total Advisory Fees Paid$4,782,765

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.8
Materials	1.8
Energy	2.5
Health Care	3.1
Real Estate	4.1
Consumer Discretionary	8.1
Communication Services	11.0
Industrials	14.9
Information Technology	53.5

Top Countries

Table Summary
Value	Value
China	0.8
Brazil	1.8
United States	97.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.1
Amazon.com, Inc.	7.2
Apple, Inc.	5.4
Alphabet, Inc.	4.9
Microsoft Corp.	4.9
Broadcom, Inc.	4.6
Databricks, Inc.	3.5
Meta Platforms, Inc.	3.5
Palo Alto Networks, Inc.	3.3
Caterpillar, Inc.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017863

Shareholder Report [Line Items]

Fund Name

BlackRock Capital Appreciation Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Capital Appreciation Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$37	0.71%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.71%

^[9]

AssetsNet

$ 1,962,769,931

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 4,782,765

InvestmentCompanyPortfolioTurnover

52.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,962,769,931
# of Portfolio Investments48
Portfolio Turnover Rate52%
Total Advisory Fees Paid$4,782,765

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.8
Materials	1.8
Energy	2.5
Health Care	3.1
Real Estate	4.1
Consumer Discretionary	8.1
Communication Services	11.0
Industrials	14.9
Information Technology	53.5

Top Countries

Table Summary
Value	Value
China	0.8
Brazil	1.8
United States	97.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.1
Amazon.com, Inc.	7.2
Apple, Inc.	5.4
Alphabet, Inc.	4.9
Microsoft Corp.	4.9
Broadcom, Inc.	4.6
Databricks, Inc.	3.5
Meta Platforms, Inc.	3.5
Palo Alto Networks, Inc.	3.3
Caterpillar, Inc.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017864

Shareholder Report [Line Items]

Fund Name

BlackRock Ultra-Short Term Bond Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Ultra-Short Term Bond Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$19	0.38%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 19

Expense Ratio, Percent

0.38%

^[10]

AssetsNet

$ 700,303,869

Holdings Count | Holding

154

Advisory Fees Paid, Amount

$ 1,184,521

InvestmentCompanyPortfolioTurnover

0.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$700,303,869
# of Portfolio Investments154
Portfolio Turnover Rate0%
Total Advisory Fees Paid$1,184,521

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Time Deposits	0.8
Certificate of Deposit	27.8
Commercial Paper	33.9
Repurchase Agreements	37.3

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
BofA Securities, Inc.	14.0
JPMorgan Securities LLC	13.0
TD Securities (USA) LLC	10.7
Macquarie Bank Ltd.	3.4
Svenska Handelsbanken AB	3.1
Royal Bank of Canada	3.0
National Bank of Canada	3.0
Verto Capital Compartment B	2.9
Bank of Montreal	2.5
BNP Paribas SA	2.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017865

Shareholder Report [Line Items]

Fund Name

BlackRock Ultra-Short Term Bond Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Ultra-Short Term Bond Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$31	0.63%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 31

Expense Ratio, Percent

0.63%

^[11]

AssetsNet

$ 700,303,869

Holdings Count | Holding

154

Advisory Fees Paid, Amount

$ 1,184,521

InvestmentCompanyPortfolioTurnover

0.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$700,303,869
# of Portfolio Investments154
Portfolio Turnover Rate0%
Total Advisory Fees Paid$1,184,521

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Time Deposits	0.8
Certificate of Deposit	27.8
Commercial Paper	33.9
Repurchase Agreements	37.3

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
BofA Securities, Inc.	14.0
JPMorgan Securities LLC	13.0
TD Securities (USA) LLC	10.7
Macquarie Bank Ltd.	3.4
Svenska Handelsbanken AB	3.1
Royal Bank of Canada	3.0
National Bank of Canada	3.0
Verto Capital Compartment B	2.9
Bank of Montreal	2.5
BNP Paribas SA	2.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017866

Shareholder Report [Line Items]

Fund Name

BlackRock Ultra-Short Term Bond Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the BlackRock Ultra-Short Term Bond Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$26	0.53%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.53%

^[12]

AssetsNet

$ 700,303,869

Holdings Count | Holding

154

Advisory Fees Paid, Amount

$ 1,184,521

InvestmentCompanyPortfolioTurnover

0.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$700,303,869
# of Portfolio Investments154
Portfolio Turnover Rate0%
Total Advisory Fees Paid$1,184,521

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Time Deposits	0.8
Certificate of Deposit	27.8
Commercial Paper	33.9
Repurchase Agreements	37.3

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
BofA Securities, Inc.	14.0
JPMorgan Securities LLC	13.0
TD Securities (USA) LLC	10.7
Macquarie Bank Ltd.	3.4
Svenska Handelsbanken AB	3.1
Royal Bank of Canada	3.0
National Bank of Canada	3.0
Verto Capital Compartment B	2.9
Bank of Montreal	2.5
BNP Paribas SA	2.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017807

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 20 Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 20 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$5	0.10%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 5

Expense Ratio, Percent

0.10%

^[13]

AssetsNet

$ 289,302,407

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 146,642

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$289,302,407
# of Portfolio Investments33
Portfolio Turnover Rate9%
Total Advisory Fees Paid$146,642

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Emerging Market Equities	0.3
Real Estate Equities	0.5
U.S. Mid Cap Equities	0.5
Global Equities	1.4
International Fixed Income	2.0
U.S. Small Cap Equities	2.0
International Developed Market Equities	3.7
High Yield Fixed Income	7.5
U.S. Large Cap Equities	12.0
Investment Grade Fixed Income	70.2

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	13.0
Western Asset Management U.S. Government Portfolio, Class A	13.0
PIMCO Total Return Portfolio, Class A	12.5
TCW Core Fixed Income Portfolio, Class A	10.0
JPMorgan Core Bond Portfolio, Class A	8.3
PIMCO Inflation Protected Bond Portfolio, Class A	8.3
Western Asset Management Strategic Bond Opportunities Portfolio, Class A	5.0
Brighthouse/Franklin Low Duration Total Return Portfolio, Class A	5.0
MFS Value Portfolio, Class A	2.5
AB International Bond Portfolio, Class A	2.0

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017808

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 20 Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 20 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$18	0.35%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 18

Expense Ratio, Percent

0.35%

^[14]

AssetsNet

$ 289,302,407

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 146,642

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$289,302,407
# of Portfolio Investments33
Portfolio Turnover Rate9%
Total Advisory Fees Paid$146,642

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Emerging Market Equities	0.3
Real Estate Equities	0.5
U.S. Mid Cap Equities	0.5
Global Equities	1.4
International Fixed Income	2.0
U.S. Small Cap Equities	2.0
International Developed Market Equities	3.7
High Yield Fixed Income	7.5
U.S. Large Cap Equities	12.0
Investment Grade Fixed Income	70.2

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	13.0
Western Asset Management U.S. Government Portfolio, Class A	13.0
PIMCO Total Return Portfolio, Class A	12.5
TCW Core Fixed Income Portfolio, Class A	10.0
JPMorgan Core Bond Portfolio, Class A	8.3
PIMCO Inflation Protected Bond Portfolio, Class A	8.3
Western Asset Management Strategic Bond Opportunities Portfolio, Class A	5.0
Brighthouse/Franklin Low Duration Total Return Portfolio, Class A	5.0
MFS Value Portfolio, Class A	2.5
AB International Bond Portfolio, Class A	2.0

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017809

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 40 Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 40 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$4	0.07%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 4

Expense Ratio, Percent

0.07%

^[15]

AssetsNet

$ 2,960,534,466

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 936,242

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,960,534,466
# of Portfolio Investments38
Portfolio Turnover Rate8%
Total Advisory Fees Paid$936,242

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Real Estate Equities	0.7
U.S. Mid Cap Equities	1.0
Emerging Market Equities	1.5
Global Equities	2.8
International Fixed Income	4.0
U.S. Small Cap Equities	4.0
High Yield Fixed Income	6.3
International Developed Market Equities	8.4
U.S. Large Cap Equities	22.3
Investment Grade Fixed Income	49.0

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	10.3
PIMCO Total Return Portfolio, Class A	10.0
Western Asset Management U.S. Government Portfolio, Class A	8.3
TCW Core Fixed Income Portfolio, Class A	7.8
PIMCO Inflation Protected Bond Portfolio, Class A	5.3
JPMorgan Core Bond Portfolio, Class A	4.3
MFS Value Portfolio, Class A	3.8
Western Asset Management Strategic Bond Opportunities Portfolio, Class A	3.5
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	3.3
Invesco Comstock Portfolio, Class A	3.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017810

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 40 Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 40 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$16	0.32%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 16

Expense Ratio, Percent

0.32%

^[16]

AssetsNet

$ 2,960,534,466

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 936,242

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,960,534,466
# of Portfolio Investments38
Portfolio Turnover Rate8%
Total Advisory Fees Paid$936,242

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Real Estate Equities	0.7
U.S. Mid Cap Equities	1.0
Emerging Market Equities	1.5
Global Equities	2.8
International Fixed Income	4.0
U.S. Small Cap Equities	4.0
High Yield Fixed Income	6.3
International Developed Market Equities	8.4
U.S. Large Cap Equities	22.3
Investment Grade Fixed Income	49.0

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	10.3
PIMCO Total Return Portfolio, Class A	10.0
Western Asset Management U.S. Government Portfolio, Class A	8.3
TCW Core Fixed Income Portfolio, Class A	7.8
PIMCO Inflation Protected Bond Portfolio, Class A	5.3
JPMorgan Core Bond Portfolio, Class A	4.3
MFS Value Portfolio, Class A	3.8
Western Asset Management Strategic Bond Opportunities Portfolio, Class A	3.5
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	3.3
Invesco Comstock Portfolio, Class A	3.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017814

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 60 Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 60 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[17]

AssetsNet

$ 8,523,872,564

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,317,126

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$8,523,872,564
# of Portfolio Investments39
Portfolio Turnover Rate10%
Total Advisory Fees Paid$2,317,126

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
U.S. Mid Cap Equities	1.0
Real Estate Equities	1.5
Emerging Market Equities	2.5
Global Equities	3.5
International Fixed Income	3.8
High Yield Fixed Income	4.4
U.S. Small Cap Equities	5.6
International Developed Market Equities	13.7
Investment Grade Fixed Income	30.8
U.S. Large Cap Equities	33.2

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	8.0
PIMCO Total Return Portfolio, Class A	6.2
TCW Core Fixed Income Portfolio, Class A	5.6
MFS Value Portfolio, Class A	5.1
Invesco Comstock Portfolio, Class A	4.8
T. Rowe Price Large Cap Value Portfolio, Class A	4.6
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	4.3
Western Asset Management U.S. Government Portfolio, Class A	4.2
Harris Oakmark International Portfolio, Class A	3.8
Baillie Gifford International Stock Portfolio, Class A	3.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017815

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 60 Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 60 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$16	0.31%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 16

Expense Ratio, Percent

0.31%

^[18]

AssetsNet

$ 8,523,872,564

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,317,126

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$8,523,872,564
# of Portfolio Investments39
Portfolio Turnover Rate10%
Total Advisory Fees Paid$2,317,126

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
U.S. Mid Cap Equities	1.0
Real Estate Equities	1.5
Emerging Market Equities	2.5
Global Equities	3.5
International Fixed Income	3.8
High Yield Fixed Income	4.4
U.S. Small Cap Equities	5.6
International Developed Market Equities	13.7
Investment Grade Fixed Income	30.8
U.S. Large Cap Equities	33.2

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
BlackRock Bond Income Portfolio, Class A	8.0
PIMCO Total Return Portfolio, Class A	6.2
TCW Core Fixed Income Portfolio, Class A	5.6
MFS Value Portfolio, Class A	5.1
Invesco Comstock Portfolio, Class A	4.8
T. Rowe Price Large Cap Value Portfolio, Class A	4.6
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	4.3
Western Asset Management U.S. Government Portfolio, Class A	4.2
Harris Oakmark International Portfolio, Class A	3.8
Baillie Gifford International Stock Portfolio, Class A	3.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017816

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 80 Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 80 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$3	0.06%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.06%

^[19]

AssetsNet

$ 8,106,318,196

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,191,084

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$8,106,318,196
# of Portfolio Investments40
Portfolio Turnover Rate9%
Total Advisory Fees Paid$2,191,084

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
International Fixed Income	1.7
Real Estate Equities	2.3
U.S. Mid Cap Equities	2.6
High Yield Fixed Income	3.0
Emerging Market Equities	3.5
Global Equities	4.2
U.S. Small Cap Equities	7.8
Investment Grade Fixed Income	13.5
International Developed Market Equities	18.5
U.S. Large Cap Equities	42.9

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
MFS Value Portfolio, Class A	5.8
Invesco Comstock Portfolio, Class A	5.6
T. Rowe Price Large Cap Value Portfolio, Class A	5.3
Jennison Growth Portfolio, Class A	4.8
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	4.6
Brighthouse/Wellington Large Cap Research Portfolio, Class A	4.6
Harris Oakmark International Portfolio, Class A	4.5
Loomis Sayles Growth Portfolio, Class A	4.5
BlackRock Bond Income Portfolio, Class A	4.4
Baillie Gifford International Stock Portfolio, Class A	4.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017817

Shareholder Report [Line Items]

Fund Name

Brighthouse Asset Allocation 80 Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse Asset Allocation 80 Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$16	0.31%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 16

Expense Ratio, Percent

0.31%

^[20]

AssetsNet

$ 8,106,318,196

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,191,084

InvestmentCompanyPortfolioTurnover

9.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$8,106,318,196
# of Portfolio Investments40
Portfolio Turnover Rate9%
Total Advisory Fees Paid$2,191,084

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
International Fixed Income	1.7
Real Estate Equities	2.3
U.S. Mid Cap Equities	2.6
High Yield Fixed Income	3.0
Emerging Market Equities	3.5
Global Equities	4.2
U.S. Small Cap Equities	7.8
Investment Grade Fixed Income	13.5
International Developed Market Equities	18.5
U.S. Large Cap Equities	42.9

Largest Holdings [Text Block]

Top 10 Holdings

Table Summary
MFS Value Portfolio, Class A	5.8
Invesco Comstock Portfolio, Class A	5.6
T. Rowe Price Large Cap Value Portfolio, Class A	5.3
Jennison Growth Portfolio, Class A	4.8
Brighthouse/Wellington Core Equity Opportunities Portfolio, Class A	4.6
Brighthouse/Wellington Large Cap Research Portfolio, Class A	4.6
Harris Oakmark International Portfolio, Class A	4.5
Loomis Sayles Growth Portfolio, Class A	4.5
BlackRock Bond Income Portfolio, Class A	4.4
Baillie Gifford International Stock Portfolio, Class A	4.3

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000069948

Shareholder Report [Line Items]

Fund Name

Brighthouse/Dimensional International Small Company Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse/Dimensional International Small Company Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$40	0.78%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 40

Expense Ratio, Percent

0.78%

^[21]

AssetsNet

$ 455,164,951

Holdings Count | Holding

3,292

Advisory Fees Paid, Amount

$ 1,511,754

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$455,164,951
# of Portfolio Investments3,292
Portfolio Turnover Rate7%
Total Advisory Fees Paid$1,511,754

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	3.4
Real Estate	4.3
Health Care	4.9
Energy	5.4
Consumer Staples	5.8
Information Technology	7.3
Consumer Discretionary	11.4
Materials	13.8
Financials	13.9
Industrials	25.6

Top 10 Countries

Table Summary
Value	Value
Finland	2.4
Sweden	2.6
Italy	3.5
Australia	5.6
France	5.7
Germany	6.5
Switzerland	8.0
United Kingdom	10.3
Canada	11.8
Japan	22.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
BAWAG Group AG	0.6
Swiss Prime Site AG	0.5
Rexel SA	0.4
Accelleron Industries AG	0.4
SPIE SA	0.4
Belimo Holding AG	0.4
Gaztransport Et Technigaz SA	0.4
Orion OYJ	0.3
Italgas SpA	0.3
PSP Swiss Property AG	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000069949

Shareholder Report [Line Items]

Fund Name

Brighthouse/Dimensional International Small Company Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$52	1.03%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 52

Expense Ratio, Percent

1.03%

^[22]

AssetsNet

$ 455,164,951

Holdings Count | Holding

3,292

Advisory Fees Paid, Amount

$ 1,511,754

InvestmentCompanyPortfolioTurnover

7.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$455,164,951
# of Portfolio Investments3,292
Portfolio Turnover Rate7%
Total Advisory Fees Paid$1,511,754

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	3.4
Real Estate	4.3
Health Care	4.9
Energy	5.4
Consumer Staples	5.8
Information Technology	7.3
Consumer Discretionary	11.4
Materials	13.8
Financials	13.9
Industrials	25.6

Top 10 Countries

Table Summary
Value	Value
Finland	2.4
Sweden	2.6
Italy	3.5
Australia	5.6
France	5.7
Germany	6.5
Switzerland	8.0
United Kingdom	10.3
Canada	11.8
Japan	22.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
BAWAG Group AG	0.6
Swiss Prime Site AG	0.5
Rexel SA	0.4
Accelleron Industries AG	0.4
SPIE SA	0.4
Belimo Holding AG	0.4
Gaztransport Et Technigaz SA	0.4
Orion OYJ	0.3
Italgas SpA	0.3
PSP Swiss Property AG	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017830

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Balanced Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse/Wellington Balanced Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$25	0.49%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.49%

^[23]

AssetsNet

$ 1,269,664,691

Holdings Count | Holding

1,522

Advisory Fees Paid, Amount

$ 2,617,425

InvestmentCompanyPortfolioTurnover

130.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,269,664,691
# of Portfolio Investments1,522
Portfolio Turnover Rate130%
Total Advisory Fees Paid$2,617,425

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	6.9
Uniform Mortgage-Backed Security, TBA	6.5
U.S. Treasury Bonds	5.6
Federal National Mortgage Association	3.8
Federal Home Loan Mortgage Corp.	2.2
Government National Mortgage Association	1.8
U.S. Treasury Inflation-Indexed Notes	0.9
Government National Mortgage Association, TBA	0.8
Federal Home Loan Mortgage Corp. STACR REMICS Trust	0.5
PRET LLC	0.4

Top 10 Countries

Table Summary
Value	Value
Italy	0.1
Jersey, Channel Islands	0.1
Romania	0.1
Israel	0.1
Canada	0.2
Bermuda	0.2
Mexico	0.3
Cayman Islands	0.8
United Kingdom	0.8
United States	103.2

Asset Allocation

Table Summary
Value	Value
Municipals	0.0^{Footnote Reference*}
Floating Rate Loans	0.3
Foreign Government	0.5
Short-Term Investments	0.9
Asset-Backed Securities	3.3
Non-Agency Mortgage-Backed Securities	5.0
Corporate Bonds & Notes	6.8
U.S. Treasury & Government Agencies	13.7
Agency Sponsored Mortgage-Backed Securities	16.8
Common Stocks	60.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	5.1
Apple, Inc.	3.3
Alphabet, Inc.	3.2
Amazon.com, Inc.	3.0
Microsoft Corp.	2.6
Broadcom, Inc.	2.2
Micron Technology, Inc.	1.7
Advanced Micro Devices, Inc.	1.2
Goldman Sachs Group, Inc.	1.1
Eli Lilly & Co.	1.0

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017831

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Balanced Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse/Wellington Balanced Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$38	0.74%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.74%

^[24]

AssetsNet

$ 1,269,664,691

Holdings Count | Holding

1,522

Advisory Fees Paid, Amount

$ 2,617,425

InvestmentCompanyPortfolioTurnover

130.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,269,664,691
# of Portfolio Investments1,522
Portfolio Turnover Rate130%
Total Advisory Fees Paid$2,617,425

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	6.9
Uniform Mortgage-Backed Security, TBA	6.5
U.S. Treasury Bonds	5.6
Federal National Mortgage Association	3.8
Federal Home Loan Mortgage Corp.	2.2
Government National Mortgage Association	1.8
U.S. Treasury Inflation-Indexed Notes	0.9
Government National Mortgage Association, TBA	0.8
Federal Home Loan Mortgage Corp. STACR REMICS Trust	0.5
PRET LLC	0.4

Top 10 Countries

Table Summary
Value	Value
Italy	0.1
Jersey, Channel Islands	0.1
Romania	0.1
Israel	0.1
Canada	0.2
Bermuda	0.2
Mexico	0.3
Cayman Islands	0.8
United Kingdom	0.8
United States	103.2

Asset Allocation

Table Summary
Value	Value
Municipals	0.0^{Footnote Reference*}
Floating Rate Loans	0.3
Foreign Government	0.5
Short-Term Investments	0.9
Asset-Backed Securities	3.3
Non-Agency Mortgage-Backed Securities	5.0
Corporate Bonds & Notes	6.8
U.S. Treasury & Government Agencies	13.7
Agency Sponsored Mortgage-Backed Securities	16.8
Common Stocks	60.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	5.1
Apple, Inc.	3.3
Alphabet, Inc.	3.2
Amazon.com, Inc.	3.0
Microsoft Corp.	2.6
Broadcom, Inc.	2.2
Micron Technology, Inc.	1.7
Advanced Micro Devices, Inc.	1.2
Goldman Sachs Group, Inc.	1.1
Eli Lilly & Co.	1.0

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017832

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Balanced Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse/Wellington Balanced Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$33	0.64%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 33

Expense Ratio, Percent

0.64%

^[25]

AssetsNet

$ 1,269,664,691

Holdings Count | Holding

1,522

Advisory Fees Paid, Amount

$ 2,617,425

InvestmentCompanyPortfolioTurnover

130.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,269,664,691
# of Portfolio Investments1,522
Portfolio Turnover Rate130%
Total Advisory Fees Paid$2,617,425

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	6.9
Uniform Mortgage-Backed Security, TBA	6.5
U.S. Treasury Bonds	5.6
Federal National Mortgage Association	3.8
Federal Home Loan Mortgage Corp.	2.2
Government National Mortgage Association	1.8
U.S. Treasury Inflation-Indexed Notes	0.9
Government National Mortgage Association, TBA	0.8
Federal Home Loan Mortgage Corp. STACR REMICS Trust	0.5
PRET LLC	0.4

Top 10 Countries

Table Summary
Value	Value
Italy	0.1
Jersey, Channel Islands	0.1
Romania	0.1
Israel	0.1
Canada	0.2
Bermuda	0.2
Mexico	0.3
Cayman Islands	0.8
United Kingdom	0.8
United States	103.2

Asset Allocation

Table Summary
Value	Value
Municipals	0.0^{Footnote Reference*}
Floating Rate Loans	0.3
Foreign Government	0.5
Short-Term Investments	0.9
Asset-Backed Securities	3.3
Non-Agency Mortgage-Backed Securities	5.0
Corporate Bonds & Notes	6.8
U.S. Treasury & Government Agencies	13.7
Agency Sponsored Mortgage-Backed Securities	16.8
Common Stocks	60.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	5.1
Apple, Inc.	3.3
Alphabet, Inc.	3.2
Amazon.com, Inc.	3.0
Microsoft Corp.	2.6
Broadcom, Inc.	2.2
Micron Technology, Inc.	1.7
Advanced Micro Devices, Inc.	1.2
Goldman Sachs Group, Inc.	1.1
Eli Lilly & Co.	1.0

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017772

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Core Equity Opportunities Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Brighthouse/Wellington Core Equity Opportunities Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$30	0.59%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.59%

^[26]

AssetsNet

$ 2,769,521,721

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,695,311

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,769,521,721
# of Portfolio Investments53
Portfolio Turnover Rate22%
Total Advisory Fees Paid$7,695,311

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	1.0
Energy	1.6
Communication Services	2.1
Materials	2.5
Consumer Staples	6.9
Consumer Discretionary	8.9
Industrials	13.5
Health Care	17.3
Financials	19.7
Information Technology	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.0
Canada	1.1
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Broadcom, Inc.	5.7
Eli Lilly & Co.	5.0
Microsoft Corp.	4.6
KLA Corp.	3.7
Mastercard, Inc.	3.5
Texas Instruments, Inc.	3.5
Apple, Inc.	3.4
Visa, Inc.	3.2
Wells Fargo & Co.	2.7
Merck & Co., Inc.	2.6

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017773

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Core Equity Opportunities Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$42	0.84%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 42

Expense Ratio, Percent

0.84%

^[27]

AssetsNet

$ 2,769,521,721

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,695,311

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,769,521,721
# of Portfolio Investments53
Portfolio Turnover Rate22%
Total Advisory Fees Paid$7,695,311

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	1.0
Energy	1.6
Communication Services	2.1
Materials	2.5
Consumer Staples	6.9
Consumer Discretionary	8.9
Industrials	13.5
Health Care	17.3
Financials	19.7
Information Technology	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.0
Canada	1.1
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Broadcom, Inc.	5.7
Eli Lilly & Co.	5.0
Microsoft Corp.	4.6
KLA Corp.	3.7
Mastercard, Inc.	3.5
Texas Instruments, Inc.	3.5
Apple, Inc.	3.4
Visa, Inc.	3.2
Wells Fargo & Co.	2.7
Merck & Co., Inc.	2.6

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017774

Shareholder Report [Line Items]

Fund Name

Brighthouse/Wellington Core Equity Opportunities Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$37	0.74%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.74%

^[28]

AssetsNet

$ 2,769,521,721

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,695,311

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,769,521,721
# of Portfolio Investments53
Portfolio Turnover Rate22%
Total Advisory Fees Paid$7,695,311

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	1.0
Energy	1.6
Communication Services	2.1
Materials	2.5
Consumer Staples	6.9
Consumer Discretionary	8.9
Industrials	13.5
Health Care	17.3
Financials	19.7
Information Technology	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.0
Canada	1.1
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Broadcom, Inc.	5.7
Eli Lilly & Co.	5.0
Microsoft Corp.	4.6
KLA Corp.	3.7
Mastercard, Inc.	3.5
Texas Instruments, Inc.	3.5
Apple, Inc.	3.4
Visa, Inc.	3.2
Wells Fargo & Co.	2.7
Merck & Co., Inc.	2.6

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017769

Shareholder Report [Line Items]

Fund Name

Frontier Mid Cap Growth Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Frontier Mid Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$37	0.69%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.69%

^[29]

AssetsNet

$ 1,082,255,545

Holdings Count | Holding

110

Advisory Fees Paid, Amount

$ 3,306,694

InvestmentCompanyPortfolioTurnover

50.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,082,255,545
# of Portfolio Investments110
Portfolio Turnover Rate50%
Total Advisory Fees Paid$3,306,694

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Real Estate	1.3
Materials	1.7
Energy	1.8
Consumer Staples	1.8
Communication Services	1.9
Financials	3.6
Consumer Discretionary	10.8
Health Care	15.2
Industrials	25.2
Information Technology	32.2

Top Countries

Table Summary
Value	Value
Japan	0.6
Netherlands	2.4
United States	93.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Royal Caribbean Cruises Ltd.	3.9
Snowflake, Inc.	3.0
XPO, Inc.	2.9
FTAI Aviation Ltd.	2.6
Datadog, Inc.	2.5
Monolithic Power Systems, Inc.	2.4
Cloudflare, Inc.	2.1
Quanta Services, Inc.	2.1
Fair Isaac Corp.	2.0
Dexcom, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017770

Shareholder Report [Line Items]

Fund Name

Frontier Mid Cap Growth Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Frontier Mid Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$50	0.94%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.94%

^[30]

AssetsNet

$ 1,082,255,545

Holdings Count | Holding

110

Advisory Fees Paid, Amount

$ 3,306,694

InvestmentCompanyPortfolioTurnover

50.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,082,255,545
# of Portfolio Investments110
Portfolio Turnover Rate50%
Total Advisory Fees Paid$3,306,694

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Real Estate	1.3
Materials	1.7
Energy	1.8
Consumer Staples	1.8
Communication Services	1.9
Financials	3.6
Consumer Discretionary	10.8
Health Care	15.2
Industrials	25.2
Information Technology	32.2

Top Countries

Table Summary
Value	Value
Japan	0.6
Netherlands	2.4
United States	93.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Royal Caribbean Cruises Ltd.	3.9
Snowflake, Inc.	3.0
XPO, Inc.	2.9
FTAI Aviation Ltd.	2.6
Datadog, Inc.	2.5
Monolithic Power Systems, Inc.	2.4
Cloudflare, Inc.	2.1
Quanta Services, Inc.	2.1
Fair Isaac Corp.	2.0
Dexcom, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000030922

Shareholder Report [Line Items]

Fund Name

Frontier Mid Cap Growth Portfolio

Class Name

Class D

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Frontier Mid Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class D	$42	0.79%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 42

Expense Ratio, Percent

0.79%

^[31]

AssetsNet

$ 1,082,255,545

Holdings Count | Holding

110

Advisory Fees Paid, Amount

$ 3,306,694

InvestmentCompanyPortfolioTurnover

50.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,082,255,545
# of Portfolio Investments110
Portfolio Turnover Rate50%
Total Advisory Fees Paid$3,306,694

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Real Estate	1.3
Materials	1.7
Energy	1.8
Consumer Staples	1.8
Communication Services	1.9
Financials	3.6
Consumer Discretionary	10.8
Health Care	15.2
Industrials	25.2
Information Technology	32.2

Top Countries

Table Summary
Value	Value
Japan	0.6
Netherlands	2.4
United States	93.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Royal Caribbean Cruises Ltd.	3.9
Snowflake, Inc.	3.0
XPO, Inc.	2.9
FTAI Aviation Ltd.	2.6
Datadog, Inc.	2.5
Monolithic Power Systems, Inc.	2.4
Cloudflare, Inc.	2.1
Quanta Services, Inc.	2.1
Fair Isaac Corp.	2.0
Dexcom, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017771

Shareholder Report [Line Items]

Fund Name

Frontier Mid Cap Growth Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Frontier Mid Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$45	0.84%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 45

Expense Ratio, Percent

0.84%

^[32]

AssetsNet

$ 1,082,255,545

Holdings Count | Holding

110

Advisory Fees Paid, Amount

$ 3,306,694

InvestmentCompanyPortfolioTurnover

50.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,082,255,545
# of Portfolio Investments110
Portfolio Turnover Rate50%
Total Advisory Fees Paid$3,306,694

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Real Estate	1.3
Materials	1.7
Energy	1.8
Consumer Staples	1.8
Communication Services	1.9
Financials	3.6
Consumer Discretionary	10.8
Health Care	15.2
Industrials	25.2
Information Technology	32.2

Top Countries

Table Summary
Value	Value
Japan	0.6
Netherlands	2.4
United States	93.8

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Royal Caribbean Cruises Ltd.	3.9
Snowflake, Inc.	3.0
XPO, Inc.	2.9
FTAI Aviation Ltd.	2.6
Datadog, Inc.	2.5
Monolithic Power Systems, Inc.	2.4
Cloudflare, Inc.	2.1
Quanta Services, Inc.	2.1
Fair Isaac Corp.	2.0
Dexcom, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017787

Shareholder Report [Line Items]

Fund Name

Invesco Value Opportunities Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Invesco Value Opportunities Portfolio (the "Portfolio") (formerly, Brighthouse/Artisan Mid Cap Value Portfolio) for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$40	0.78%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 40

Expense Ratio, Percent

0.78%

^[33]

AssetsNet

$ 638,363,951

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,249,767

InvestmentCompanyPortfolioTurnover

113.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$638,363,951
# of Portfolio Investments93
Portfolio Turnover Rate113%
Total Advisory Fees Paid$2,249,767

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	1.4
Consumer Discretionary	3.0
Utilities	3.5
Materials	7.5
Energy	12.4
Industrials	12.6
Financials	12.6
Health Care	15.5
Information Technology	28.9

Top Countries

Table Summary
Value	Value
Netherlands	0.6
South Korea	1.0
United Kingdom	1.9
Singapore	2.7
Canada	3.8
United States	87.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Coherent Corp.	4.3
MKS, Inc.	4.2
Marvell Technology, Inc.	3.0
Rambus, Inc.	2.9
Entegris, Inc.	2.9
STMicroelectronics NV	2.7
Vertiv Holdings Co.	2.0
Waters Corp.	1.9
NRG Energy, Inc.	1.9
Globe Life, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017788

Shareholder Report [Line Items]

Fund Name

Invesco Value Opportunities Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$52	1.03%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 52

Expense Ratio, Percent

1.03%

^[34]

AssetsNet

$ 638,363,951

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,249,767

InvestmentCompanyPortfolioTurnover

113.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$638,363,951
# of Portfolio Investments93
Portfolio Turnover Rate113%
Total Advisory Fees Paid$2,249,767

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	1.4
Consumer Discretionary	3.0
Utilities	3.5
Materials	7.5
Energy	12.4
Industrials	12.6
Financials	12.6
Health Care	15.5
Information Technology	28.9

Top Countries

Table Summary
Value	Value
Netherlands	0.6
South Korea	1.0
United Kingdom	1.9
Singapore	2.7
Canada	3.8
United States	87.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Coherent Corp.	4.3
MKS, Inc.	4.2
Marvell Technology, Inc.	3.0
Rambus, Inc.	2.9
Entegris, Inc.	2.9
STMicroelectronics NV	2.7
Vertiv Holdings Co.	2.0
Waters Corp.	1.9
NRG Energy, Inc.	1.9
Globe Life, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017789

Shareholder Report [Line Items]

Fund Name

Invesco Value Opportunities Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$47	0.93%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 47

Expense Ratio, Percent

0.93%

^[35]

AssetsNet

$ 638,363,951

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,249,767

InvestmentCompanyPortfolioTurnover

113.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$638,363,951
# of Portfolio Investments93
Portfolio Turnover Rate113%
Total Advisory Fees Paid$2,249,767

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	1.4
Consumer Discretionary	3.0
Utilities	3.5
Materials	7.5
Energy	12.4
Industrials	12.6
Financials	12.6
Health Care	15.5
Information Technology	28.9

Top Countries

Table Summary
Value	Value
Netherlands	0.6
South Korea	1.0
United Kingdom	1.9
Singapore	2.7
Canada	3.8
United States	87.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Coherent Corp.	4.3
MKS, Inc.	4.2
Marvell Technology, Inc.	3.0
Rambus, Inc.	2.9
Entegris, Inc.	2.9
STMicroelectronics NV	2.7
Vertiv Holdings Co.	2.0
Waters Corp.	1.9
NRG Energy, Inc.	1.9
Globe Life, Inc.	1.9

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017793

Shareholder Report [Line Items]

Fund Name

Jennison Growth Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Jennison Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$27	0.54%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 27

Expense Ratio, Percent

0.54%

^[36]

AssetsNet

$ 2,872,461,475

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,145,777

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,872,461,475
# of Portfolio Investments59
Portfolio Turnover Rate11%
Total Advisory Fees Paid$7,145,777

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Utilities	1.1
Consumer Staples	2.9
Financials	5.2
Industrials	5.6
Health Care	7.0
Consumer Discretionary	12.7
Communication Services	15.5
Information Technology	49.9

Top Countries

Table Summary
Value	Value
Brazil	0.4
Canada	0.5
Taiwan	2.5
United States	96.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	10.5
Alphabet, Inc.	7.7
Apple, Inc.	6.8
Broadcom, Inc.	6.6
Amazon.com, Inc.	5.9
Eli Lilly & Co.	5.1
Microsoft Corp.	4.4
Advanced Micro Devices, Inc.	4.2
Meta Platforms, Inc.	3.3
General Electric Co.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017794

Shareholder Report [Line Items]

Fund Name

Jennison Growth Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Jennison Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$40	0.79%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 40

Expense Ratio, Percent

0.79%

^[37]

AssetsNet

$ 2,872,461,475

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,145,777

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,872,461,475
# of Portfolio Investments59
Portfolio Turnover Rate11%
Total Advisory Fees Paid$7,145,777

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Utilities	1.1
Consumer Staples	2.9
Financials	5.2
Industrials	5.6
Health Care	7.0
Consumer Discretionary	12.7
Communication Services	15.5
Information Technology	49.9

Top Countries

Table Summary
Value	Value
Brazil	0.4
Canada	0.5
Taiwan	2.5
United States	96.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	10.5
Alphabet, Inc.	7.7
Apple, Inc.	6.8
Broadcom, Inc.	6.6
Amazon.com, Inc.	5.9
Eli Lilly & Co.	5.1
Microsoft Corp.	4.4
Advanced Micro Devices, Inc.	4.2
Meta Platforms, Inc.	3.3
General Electric Co.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017795

Shareholder Report [Line Items]

Fund Name

Jennison Growth Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Jennison Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$35	0.69%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.69%

^[38]

AssetsNet

$ 2,872,461,475

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,145,777

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,872,461,475
# of Portfolio Investments59
Portfolio Turnover Rate11%
Total Advisory Fees Paid$7,145,777

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Utilities	1.1
Consumer Staples	2.9
Financials	5.2
Industrials	5.6
Health Care	7.0
Consumer Discretionary	12.7
Communication Services	15.5
Information Technology	49.9

Top Countries

Table Summary
Value	Value
Brazil	0.4
Canada	0.5
Taiwan	2.5
United States	96.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	10.5
Alphabet, Inc.	7.7
Apple, Inc.	6.8
Broadcom, Inc.	6.6
Amazon.com, Inc.	5.9
Eli Lilly & Co.	5.1
Microsoft Corp.	4.4
Advanced Micro Devices, Inc.	4.2
Meta Platforms, Inc.	3.3
General Electric Co.	3.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017799

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Core Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Core Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$50	0.90%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.90%

^[39]

AssetsNet

$ 405,433,764

Holdings Count | Holding

207

Advisory Fees Paid, Amount

$ 1,510,012

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$405,433,764
# of Portfolio Investments207
Portfolio Turnover Rate18%
Total Advisory Fees Paid$1,510,012

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	1.9
Real Estate	2.6
Utilities	2.7
Materials	3.0
Energy	6.7
Consumer Discretionary	10.6
Information Technology	13.6
Health Care	13.6
Financials	17.8
Industrials	25.4

Top 10 Countries

Table Summary
Value	Value
Mexico	0.2
Bahamas	0.3
Taiwan	0.4
Japan	0.4
Costa Rica	0.5
United Kingdom	1.1
Puerto Rico	1.3
Canada	2.0
Switzerland	2.4
United States	90.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Moog, Inc.	1.9
Garrett Motion, Inc.	1.8
Bel Fuse, Inc.	1.4
Popular, Inc.	1.3
Kodiak Gas Services, Inc.	1.3
TD SYNNEX Corp.	1.3
Arcosa, Inc.	1.2
Ameris Bancorp	1.2
Ultra Clean Holdings, Inc.	1.2
YETI Holdings, Inc.	1.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017800

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Core Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Core Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$64	1.15%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 64

Expense Ratio, Percent

1.15%

^[40]

AssetsNet

$ 405,433,764

Holdings Count | Holding

207

Advisory Fees Paid, Amount

$ 1,510,012

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$405,433,764
# of Portfolio Investments207
Portfolio Turnover Rate18%
Total Advisory Fees Paid$1,510,012

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	1.9
Real Estate	2.6
Utilities	2.7
Materials	3.0
Energy	6.7
Consumer Discretionary	10.6
Information Technology	13.6
Health Care	13.6
Financials	17.8
Industrials	25.4

Top 10 Countries

Table Summary
Value	Value
Mexico	0.2
Bahamas	0.3
Taiwan	0.4
Japan	0.4
Costa Rica	0.5
United Kingdom	1.1
Puerto Rico	1.3
Canada	2.0
Switzerland	2.4
United States	90.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Moog, Inc.	1.9
Garrett Motion, Inc.	1.8
Bel Fuse, Inc.	1.4
Popular, Inc.	1.3
Kodiak Gas Services, Inc.	1.3
TD SYNNEX Corp.	1.3
Arcosa, Inc.	1.2
Ameris Bancorp	1.2
Ultra Clean Holdings, Inc.	1.2
YETI Holdings, Inc.	1.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017801

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Core Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Core Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$58	1.05%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 58

Expense Ratio, Percent

1.05%

^[41]

AssetsNet

$ 405,433,764

Holdings Count | Holding

207

Advisory Fees Paid, Amount

$ 1,510,012

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$405,433,764
# of Portfolio Investments207
Portfolio Turnover Rate18%
Total Advisory Fees Paid$1,510,012

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	1.9
Real Estate	2.6
Utilities	2.7
Materials	3.0
Energy	6.7
Consumer Discretionary	10.6
Information Technology	13.6
Health Care	13.6
Financials	17.8
Industrials	25.4

Top 10 Countries

Table Summary
Value	Value
Mexico	0.2
Bahamas	0.3
Taiwan	0.4
Japan	0.4
Costa Rica	0.5
United Kingdom	1.1
Puerto Rico	1.3
Canada	2.0
Switzerland	2.4
United States	90.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Moog, Inc.	1.9
Garrett Motion, Inc.	1.8
Bel Fuse, Inc.	1.4
Popular, Inc.	1.3
Kodiak Gas Services, Inc.	1.3
TD SYNNEX Corp.	1.3
Arcosa, Inc.	1.2
Ameris Bancorp	1.2
Ultra Clean Holdings, Inc.	1.2
YETI Holdings, Inc.	1.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017784

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Growth Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$50	0.89%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.89%

^[42]

AssetsNet

$ 352,448,170

Holdings Count | Holding

109

Advisory Fees Paid, Amount

$ 1,341,091

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$352,448,170
# of Portfolio Investments109
Portfolio Turnover Rate20%
Total Advisory Fees Paid$1,341,091

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	2.5
Energy	3.2
Financials	8.3
Consumer Discretionary	10.3
Information Technology	20.1
Industrials	26.5
Health Care	28.3

Top Countries

Table Summary
Value	Value
Guernsey, Channel Islands	0.7
Canada	0.8
Mexico	0.9
Bahamas	1.2
Taiwan	1.3
United Kingdom	1.4
Japan	1.5
Costa Rica	1.8
United States	89.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Ligand Pharmaceuticals, Inc.	2.2
ESCO Technologies, Inc.	2.2
RBC Bearings, Inc.	2.1
Mercury Systems, Inc.	2.0
Extreme Networks, Inc.	2.0
ATI, Inc.	1.9
MACOM Technology Solutions Holdings, Inc.	1.9
Advanced Energy Industries, Inc.	1.9
Establishment Labs Holdings, Inc.	1.8
MYR Group, Inc.	1.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017785

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Growth Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$65	1.14%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 65

Expense Ratio, Percent

1.14%

^[43]

AssetsNet

$ 352,448,170

Holdings Count | Holding

109

Advisory Fees Paid, Amount

$ 1,341,091

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$352,448,170
# of Portfolio Investments109
Portfolio Turnover Rate20%
Total Advisory Fees Paid$1,341,091

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	2.5
Energy	3.2
Financials	8.3
Consumer Discretionary	10.3
Information Technology	20.1
Industrials	26.5
Health Care	28.3

Top Countries

Table Summary
Value	Value
Guernsey, Channel Islands	0.7
Canada	0.8
Mexico	0.9
Bahamas	1.2
Taiwan	1.3
United Kingdom	1.4
Japan	1.5
Costa Rica	1.8
United States	89.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Ligand Pharmaceuticals, Inc.	2.2
ESCO Technologies, Inc.	2.2
RBC Bearings, Inc.	2.1
Mercury Systems, Inc.	2.0
Extreme Networks, Inc.	2.0
ATI, Inc.	1.9
MACOM Technology Solutions Holdings, Inc.	1.9
Advanced Energy Industries, Inc.	1.9
Establishment Labs Holdings, Inc.	1.8
MYR Group, Inc.	1.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017786

Shareholder Report [Line Items]

Fund Name

Loomis Sayles Small Cap Growth Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Loomis Sayles Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$59	1.04%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 59

Expense Ratio, Percent

1.04%

^[44]

AssetsNet

$ 352,448,170

Holdings Count | Holding

109

Advisory Fees Paid, Amount

$ 1,341,091

InvestmentCompanyPortfolioTurnover

20.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$352,448,170
# of Portfolio Investments109
Portfolio Turnover Rate20%
Total Advisory Fees Paid$1,341,091

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	2.5
Energy	3.2
Financials	8.3
Consumer Discretionary	10.3
Information Technology	20.1
Industrials	26.5
Health Care	28.3

Top Countries

Table Summary
Value	Value
Guernsey, Channel Islands	0.7
Canada	0.8
Mexico	0.9
Bahamas	1.2
Taiwan	1.3
United Kingdom	1.4
Japan	1.5
Costa Rica	1.8
United States	89.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Ligand Pharmaceuticals, Inc.	2.2
ESCO Technologies, Inc.	2.2
RBC Bearings, Inc.	2.1
Mercury Systems, Inc.	2.0
Extreme Networks, Inc.	2.0
ATI, Inc.	1.9
MACOM Technology Solutions Holdings, Inc.	1.9
Advanced Energy Industries, Inc.	1.9
Establishment Labs Holdings, Inc.	1.8
MYR Group, Inc.	1.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017796

Shareholder Report [Line Items]

Fund Name

MetLife Aggregate Bond Index Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Aggregate Bond Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$13	0.26%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 13

Expense Ratio, Percent

0.26%

^[45]

AssetsNet

$ 3,385,558,058

Holdings Count | Holding

1,747

Advisory Fees Paid, Amount

$ 3,900,427

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$3,385,558,058
# of Portfolio Investments1,747
Portfolio Turnover Rate10%
Total Advisory Fees Paid$3,900,427

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Short-Term Investments	0.3
Asset-Backed Securities	0.4
Municipals	0.5
Non-Agency Mortgage-Backed Securities	0.6
Foreign Government	1.7
Agency Sponsored Mortgage-Backed Securities	24.2
Corporate Bonds & Notes	25.3
U.S. Treasury & Government Agencies	46.1

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	35.9
Federal National Mortgage Association	10.7
U.S. Treasury Bonds	9.7
Federal Home Loan Mortgage Corp.	7.4
Government National Mortgage Association	5.6
Federal Home Loan Mortgage Corp. Multifamily Structured Pass-Through Certificates	0.7
JPMorgan Chase & Co.	0.6
Bank of America Corp.	0.5
International Bank for Reconstruction & Development	0.4
Goldman Sachs Group, Inc.	0.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017797

Shareholder Report [Line Items]

Fund Name

MetLife Aggregate Bond Index Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Aggregate Bond Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$25	0.51%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.51%

^[46]

AssetsNet

$ 3,385,558,058

Holdings Count | Holding

1,747

Advisory Fees Paid, Amount

$ 3,900,427

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$3,385,558,058
# of Portfolio Investments1,747
Portfolio Turnover Rate10%
Total Advisory Fees Paid$3,900,427

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Short-Term Investments	0.3
Asset-Backed Securities	0.4
Municipals	0.5
Non-Agency Mortgage-Backed Securities	0.6
Foreign Government	1.7
Agency Sponsored Mortgage-Backed Securities	24.2
Corporate Bonds & Notes	25.3
U.S. Treasury & Government Agencies	46.1

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	35.9
Federal National Mortgage Association	10.7
U.S. Treasury Bonds	9.7
Federal Home Loan Mortgage Corp.	7.4
Government National Mortgage Association	5.6
Federal Home Loan Mortgage Corp. Multifamily Structured Pass-Through Certificates	0.7
JPMorgan Chase & Co.	0.6
Bank of America Corp.	0.5
International Bank for Reconstruction & Development	0.4
Goldman Sachs Group, Inc.	0.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017798

Shareholder Report [Line Items]

Fund Name

MetLife Aggregate Bond Index Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Aggregate Bond Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$20	0.41%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 20

Expense Ratio, Percent

0.41%

^[47]

AssetsNet

$ 3,385,558,058

Holdings Count | Holding

1,747

Advisory Fees Paid, Amount

$ 3,900,427

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$3,385,558,058
# of Portfolio Investments1,747
Portfolio Turnover Rate10%
Total Advisory Fees Paid$3,900,427

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Short-Term Investments	0.3
Asset-Backed Securities	0.4
Municipals	0.5
Non-Agency Mortgage-Backed Securities	0.6
Foreign Government	1.7
Agency Sponsored Mortgage-Backed Securities	24.2
Corporate Bonds & Notes	25.3
U.S. Treasury & Government Agencies	46.1

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	35.9
Federal National Mortgage Association	10.7
U.S. Treasury Bonds	9.7
Federal Home Loan Mortgage Corp.	7.4
Government National Mortgage Association	5.6
Federal Home Loan Mortgage Corp. Multifamily Structured Pass-Through Certificates	0.7
JPMorgan Chase & Co.	0.6
Bank of America Corp.	0.5
International Bank for Reconstruction & Development	0.4
Goldman Sachs Group, Inc.	0.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000075817

Shareholder Report [Line Items]

Fund Name

MetLife Aggregate Bond Index Portfolio

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Aggregate Bond Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$28	0.56%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 28

Expense Ratio, Percent

0.56%

^[48]

AssetsNet

$ 3,385,558,058

Holdings Count | Holding

1,747

Advisory Fees Paid, Amount

$ 3,900,427

InvestmentCompanyPortfolioTurnover

10.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$3,385,558,058
# of Portfolio Investments1,747
Portfolio Turnover Rate10%
Total Advisory Fees Paid$3,900,427

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Short-Term Investments	0.3
Asset-Backed Securities	0.4
Municipals	0.5
Non-Agency Mortgage-Backed Securities	0.6
Foreign Government	1.7
Agency Sponsored Mortgage-Backed Securities	24.2
Corporate Bonds & Notes	25.3
U.S. Treasury & Government Agencies	46.1

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	35.9
Federal National Mortgage Association	10.7
U.S. Treasury Bonds	9.7
Federal Home Loan Mortgage Corp.	7.4
Government National Mortgage Association	5.6
Federal Home Loan Mortgage Corp. Multifamily Structured Pass-Through Certificates	0.7
JPMorgan Chase & Co.	0.6
Bank of America Corp.	0.5
International Bank for Reconstruction & Development	0.4
Goldman Sachs Group, Inc.	0.4

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017811

Shareholder Report [Line Items]

Fund Name

MetLife Mid Cap Stock Index Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Mid Cap Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$16	0.30%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 16

Expense Ratio, Percent

0.30%

^[49]

AssetsNet

$ 1,237,232,431

Holdings Count | Holding

427

Advisory Fees Paid, Amount

$ 1,456,499

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,237,232,431
# of Portfolio Investments427
Portfolio Turnover Rate17%
Total Advisory Fees Paid$1,456,499

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	2.9
Consumer Staples	3.0
Energy	4.2
Materials	5.4
Real Estate	6.4
Health Care	8.4
Consumer Discretionary	10.3
Financials	14.3
Information Technology	15.0
Industrials	25.5

Top Countries

Table Summary
Value	Value
Sweden	0.2
Japan	0.2
Bermuda	0.4
Thailand	0.6
Canada	0.6
United Kingdom	0.7
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
State Street SPDR S&P MidCap 400 ETF Trust	2.1
Twilio, Inc.	0.8
Carpenter Technology Corp.	0.8
MKS, Inc.	0.8
Curtiss-Wright Corp.	0.7
nVent Electric PLC	0.7
Entegris, Inc.	0.7
ATI, Inc.	0.7
Illumina, Inc.	0.7
TechnipFMC PLC	0.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017812

Shareholder Report [Line Items]

Fund Name

MetLife Mid Cap Stock Index Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Mid Cap Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$30	0.55%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.55%

^[50]

AssetsNet

$ 1,237,232,431

Holdings Count | Holding

427

Advisory Fees Paid, Amount

$ 1,456,499

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,237,232,431
# of Portfolio Investments427
Portfolio Turnover Rate17%
Total Advisory Fees Paid$1,456,499

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	2.9
Consumer Staples	3.0
Energy	4.2
Materials	5.4
Real Estate	6.4
Health Care	8.4
Consumer Discretionary	10.3
Financials	14.3
Information Technology	15.0
Industrials	25.5

Top Countries

Table Summary
Value	Value
Sweden	0.2
Japan	0.2
Bermuda	0.4
Thailand	0.6
Canada	0.6
United Kingdom	0.7
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
State Street SPDR S&P MidCap 400 ETF Trust	2.1
Twilio, Inc.	0.8
Carpenter Technology Corp.	0.8
MKS, Inc.	0.8
Curtiss-Wright Corp.	0.7
nVent Electric PLC	0.7
Entegris, Inc.	0.7
ATI, Inc.	0.7
Illumina, Inc.	0.7
TechnipFMC PLC	0.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017813

Shareholder Report [Line Items]

Fund Name

MetLife Mid Cap Stock Index Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Mid Cap Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$24	0.45%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 24

Expense Ratio, Percent

0.45%

^[51]

AssetsNet

$ 1,237,232,431

Holdings Count | Holding

427

Advisory Fees Paid, Amount

$ 1,456,499

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,237,232,431
# of Portfolio Investments427
Portfolio Turnover Rate17%
Total Advisory Fees Paid$1,456,499

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	2.9
Consumer Staples	3.0
Energy	4.2
Materials	5.4
Real Estate	6.4
Health Care	8.4
Consumer Discretionary	10.3
Financials	14.3
Information Technology	15.0
Industrials	25.5

Top Countries

Table Summary
Value	Value
Sweden	0.2
Japan	0.2
Bermuda	0.4
Thailand	0.6
Canada	0.6
United Kingdom	0.7
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
State Street SPDR S&P MidCap 400 ETF Trust	2.1
Twilio, Inc.	0.8
Carpenter Technology Corp.	0.8
MKS, Inc.	0.8
Curtiss-Wright Corp.	0.7
nVent Electric PLC	0.7
Entegris, Inc.	0.7
ATI, Inc.	0.7
Illumina, Inc.	0.7
TechnipFMC PLC	0.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000075818

Shareholder Report [Line Items]

Fund Name

MetLife Mid Cap Stock Index Portfolio

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Mid Cap Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$32	0.60%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 32

Expense Ratio, Percent

0.60%

^[52]

AssetsNet

$ 1,237,232,431

Holdings Count | Holding

427

Advisory Fees Paid, Amount

$ 1,456,499

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,237,232,431
# of Portfolio Investments427
Portfolio Turnover Rate17%
Total Advisory Fees Paid$1,456,499

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Utilities	2.9
Consumer Staples	3.0
Energy	4.2
Materials	5.4
Real Estate	6.4
Health Care	8.4
Consumer Discretionary	10.3
Financials	14.3
Information Technology	15.0
Industrials	25.5

Top Countries

Table Summary
Value	Value
Sweden	0.2
Japan	0.2
Bermuda	0.4
Thailand	0.6
Canada	0.6
United Kingdom	0.7
United States	96.4

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
State Street SPDR S&P MidCap 400 ETF Trust	2.1
Twilio, Inc.	0.8
Carpenter Technology Corp.	0.8
MKS, Inc.	0.8
Curtiss-Wright Corp.	0.7
nVent Electric PLC	0.7
Entegris, Inc.	0.7
ATI, Inc.	0.7
Illumina, Inc.	0.7
TechnipFMC PLC	0.7

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017827

Shareholder Report [Line Items]

Fund Name

MetLife MSCI EAFE<sup style="inset: 1.5px 0px 4px; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 700; grid-area: auto; line-height: 0px; margin: 0px; overflow: visible; position: relative; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">® Index Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife MSCI EAFE^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$18	0.35%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 18

Expense Ratio, Percent

0.35%

^[53]

AssetsNet

$ 1,562,656,070

Holdings Count | Holding

693

Advisory Fees Paid, Amount

$ 2,183,857

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,562,656,070
# of Portfolio Investments693
Portfolio Turnover Rate14%
Total Advisory Fees Paid$2,183,857

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Energy	3.1
Communication Services	3.6
Utilities	3.7
Materials	5.7
Consumer Staples	6.4
Consumer Discretionary	7.8
Health Care	9.8
Information Technology	11.6
Industrials	18.0
Financials	23.7

Top 10 Countries

Table Summary
Value	Value
Italy	3.2
Spain	3.6
Netherlands	5.8
Switzerland	6.0
Australia	6.8
France	7.8
Germany	8.2
United States	9.7
United Kingdom	10.5
Japan	22.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
ASML Holding NV	3.4
iShares MSCI EAFE ETF	2.7
HSBC Holdings PLC	1.4
Roche Holding AG	1.3
Novartis AG	1.3
AstraZeneca PLC	1.3
Nestle SA	1.2
Siemens AG	1.1
Shell PLC	1.0
Tokyo Electron Ltd.	1.0

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017828

Shareholder Report [Line Items]

Fund Name

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife MSCI EAFE^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$31	0.60%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 31

Expense Ratio, Percent

0.60%

^[54]

AssetsNet

$ 1,562,656,070

Holdings Count | Holding

693

Advisory Fees Paid, Amount

$ 2,183,857

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,562,656,070
# of Portfolio Investments693
Portfolio Turnover Rate14%
Total Advisory Fees Paid$2,183,857

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Energy	3.1
Communication Services	3.6
Utilities	3.7
Materials	5.7
Consumer Staples	6.4
Consumer Discretionary	7.8
Health Care	9.8
Information Technology	11.6
Industrials	18.0
Financials	23.7

Top 10 Countries

Table Summary
Value	Value
Italy	3.2
Spain	3.6
Netherlands	5.8
Switzerland	6.0
Australia	6.8
France	7.8
Germany	8.2
United States	9.7
United Kingdom	10.5
Japan	22.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
ASML Holding NV	3.4
iShares MSCI EAFE ETF	2.7
HSBC Holdings PLC	1.4
Roche Holding AG	1.3
Novartis AG	1.3
AstraZeneca PLC	1.3
Nestle SA	1.2
Siemens AG	1.1
Shell PLC	1.0
Tokyo Electron Ltd.	1.0

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017829

Shareholder Report [Line Items]

Fund Name

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife MSCI EAFE^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$26	0.50%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 26

Expense Ratio, Percent

0.50%

^[55]

AssetsNet

$ 1,562,656,070

Holdings Count | Holding

693

Advisory Fees Paid, Amount

$ 2,183,857

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,562,656,070
# of Portfolio Investments693
Portfolio Turnover Rate14%
Total Advisory Fees Paid$2,183,857

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Energy	3.1
Communication Services	3.6
Utilities	3.7
Materials	5.7
Consumer Staples	6.4
Consumer Discretionary	7.8
Health Care	9.8
Information Technology	11.6
Industrials	18.0
Financials	23.7

Top 10 Countries

Table Summary
Value	Value
Italy	3.2
Spain	3.6
Netherlands	5.8
Switzerland	6.0
Australia	6.8
France	7.8
Germany	8.2
United States	9.7
United Kingdom	10.5
Japan	22.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
ASML Holding NV	3.4
iShares MSCI EAFE ETF	2.7
HSBC Holdings PLC	1.4
Roche Holding AG	1.3
Novartis AG	1.3
AstraZeneca PLC	1.3
Nestle SA	1.2
Siemens AG	1.1
Shell PLC	1.0
Tokyo Electron Ltd.	1.0

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000075820

Shareholder Report [Line Items]

Fund Name

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife MSCI EAFE^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$34	0.65%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 34

Expense Ratio, Percent

0.65%

^[56]

AssetsNet

$ 1,562,656,070

Holdings Count | Holding

693

Advisory Fees Paid, Amount

$ 2,183,857

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,562,656,070
# of Portfolio Investments693
Portfolio Turnover Rate14%
Total Advisory Fees Paid$2,183,857

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Energy	3.1
Communication Services	3.6
Utilities	3.7
Materials	5.7
Consumer Staples	6.4
Consumer Discretionary	7.8
Health Care	9.8
Information Technology	11.6
Industrials	18.0
Financials	23.7

Top 10 Countries

Table Summary
Value	Value
Italy	3.2
Spain	3.6
Netherlands	5.8
Switzerland	6.0
Australia	6.8
France	7.8
Germany	8.2
United States	9.7
United Kingdom	10.5
Japan	22.5

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
ASML Holding NV	3.4
iShares MSCI EAFE ETF	2.7
HSBC Holdings PLC	1.4
Roche Holding AG	1.3
Novartis AG	1.3
AstraZeneca PLC	1.3
Nestle SA	1.2
Siemens AG	1.1
Shell PLC	1.0
Tokyo Electron Ltd.	1.0

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017839

Shareholder Report [Line Items]

Fund Name

MetLife Russell 2000<sup style="inset: 1.5px 0px 4px; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 700; grid-area: auto; line-height: 0px; margin: 0px; overflow: visible; position: relative; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">® Index Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Russell 2000^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$17	0.30%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 17

Expense Ratio, Percent

0.30%

^[57]

AssetsNet

$ 1,090,052,097

Holdings Count | Holding

1,839

Advisory Fees Paid, Amount

$ 1,263,371

InvestmentCompanyPortfolioTurnover

30.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,090,052,097
# of Portfolio Investments1,839
Portfolio Turnover Rate30%
Total Advisory Fees Paid$1,263,371

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.4
Utilities	2.6
Materials	4.1
Energy	5.6
Real Estate	5.7
Consumer Discretionary	9.2
Information Technology	13.9
Industrials	14.5
Financials	18.0
Health Care	19.5

Top 10 Countries

Table Summary
Value	Value
Monaco	0.1
Cameroon	0.1
Bermuda	0.2
Norway	0.2
United Kingdom	0.2
Singapore	0.2
Puerto Rico	0.3
Switzerland	0.4
Canada	1.1
United States	94.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
iShares Russell 2000 ETF	0.4
Moog, Inc.	0.4
Hut 8 Corp.	0.4
Viasat, Inc.	0.3
BrightSpring Health Services, Inc.	0.3
Cytokinetics, Inc.	0.3
MaxLinear, Inc.	0.3
Argan, Inc.	0.3
UMB Financial Corp.	0.3
JFrog Ltd.	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017840

Shareholder Report [Line Items]

Fund Name

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Russell 2000^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$30	0.55%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.55%

^[58]

AssetsNet

$ 1,090,052,097

Holdings Count | Holding

1,839

Advisory Fees Paid, Amount

$ 1,263,371

InvestmentCompanyPortfolioTurnover

30.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,090,052,097
# of Portfolio Investments1,839
Portfolio Turnover Rate30%
Total Advisory Fees Paid$1,263,371

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.4
Utilities	2.6
Materials	4.1
Energy	5.6
Real Estate	5.7
Consumer Discretionary	9.2
Information Technology	13.9
Industrials	14.5
Financials	18.0
Health Care	19.5

Top 10 Countries

Table Summary
Value	Value
Monaco	0.1
Cameroon	0.1
Bermuda	0.2
Norway	0.2
United Kingdom	0.2
Singapore	0.2
Puerto Rico	0.3
Switzerland	0.4
Canada	1.1
United States	94.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
iShares Russell 2000 ETF	0.4
Moog, Inc.	0.4
Hut 8 Corp.	0.4
Viasat, Inc.	0.3
BrightSpring Health Services, Inc.	0.3
Cytokinetics, Inc.	0.3
MaxLinear, Inc.	0.3
Argan, Inc.	0.3
UMB Financial Corp.	0.3
JFrog Ltd.	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017841

Shareholder Report [Line Items]

Fund Name

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Russell 2000^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$25	0.45%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.45%

^[59]

AssetsNet

$ 1,090,052,097

Holdings Count | Holding

1,839

Advisory Fees Paid, Amount

$ 1,263,371

InvestmentCompanyPortfolioTurnover

30.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,090,052,097
# of Portfolio Investments1,839
Portfolio Turnover Rate30%
Total Advisory Fees Paid$1,263,371

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.4
Utilities	2.6
Materials	4.1
Energy	5.6
Real Estate	5.7
Consumer Discretionary	9.2
Information Technology	13.9
Industrials	14.5
Financials	18.0
Health Care	19.5

Top 10 Countries

Table Summary
Value	Value
Monaco	0.1
Cameroon	0.1
Bermuda	0.2
Norway	0.2
United Kingdom	0.2
Singapore	0.2
Puerto Rico	0.3
Switzerland	0.4
Canada	1.1
United States	94.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
iShares Russell 2000 ETF	0.4
Moog, Inc.	0.4
Hut 8 Corp.	0.4
Viasat, Inc.	0.3
BrightSpring Health Services, Inc.	0.3
Cytokinetics, Inc.	0.3
MaxLinear, Inc.	0.3
Argan, Inc.	0.3
UMB Financial Corp.	0.3
JFrog Ltd.	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000075821

Shareholder Report [Line Items]

Fund Name

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Russell 2000^® Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$33	0.60%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 33

Expense Ratio, Percent

0.60%

^[60]

AssetsNet

$ 1,090,052,097

Holdings Count | Holding

1,839

Advisory Fees Paid, Amount

$ 1,263,371

InvestmentCompanyPortfolioTurnover

30.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,090,052,097
# of Portfolio Investments1,839
Portfolio Turnover Rate30%
Total Advisory Fees Paid$1,263,371

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.4
Utilities	2.6
Materials	4.1
Energy	5.6
Real Estate	5.7
Consumer Discretionary	9.2
Information Technology	13.9
Industrials	14.5
Financials	18.0
Health Care	19.5

Top 10 Countries

Table Summary
Value	Value
Monaco	0.1
Cameroon	0.1
Bermuda	0.2
Norway	0.2
United Kingdom	0.2
Singapore	0.2
Puerto Rico	0.3
Switzerland	0.4
Canada	1.1
United States	94.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
iShares Russell 2000 ETF	0.4
Moog, Inc.	0.4
Hut 8 Corp.	0.4
Viasat, Inc.	0.3
BrightSpring Health Services, Inc.	0.3
Cytokinetics, Inc.	0.3
MaxLinear, Inc.	0.3
Argan, Inc.	0.3
UMB Financial Corp.	0.3
JFrog Ltd.	0.3

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017818

Shareholder Report [Line Items]

Fund Name

MetLife Stock Index Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$14	0.27%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 14

Expense Ratio, Percent

0.27%

^[61]

AssetsNet

$ 9,680,787,851

Holdings Count | Holding

567

Advisory Fees Paid, Amount

$ 10,948,523

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$9,680,787,851
# of Portfolio Investments567
Portfolio Turnover Rate6%
Total Advisory Fees Paid$10,948,523

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	1.8
Utilities	2.2
Energy	2.9
Consumer Staples	4.5
Health Care	8.8
Industrials	8.8
Consumer Discretionary	9.2
Communication Services	9.6
Financials	11.6
Information Technology	37.6

Top Countries

Table Summary
Value	Value
Switzerland	0.1
Netherlands	0.1
United States	99.3

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	7.4
Apple, Inc.	6.5
Alphabet, Inc.	5.8
Microsoft Corp.	4.2
Amazon.com, Inc.	3.6
Broadcom, Inc.	2.7
Micron Technology, Inc.	2.0
Meta Platforms, Inc.	1.9
Tesla, Inc.	1.8
Eli Lilly & Co.	1.5

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017819

Shareholder Report [Line Items]

Fund Name

MetLife Stock Index Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$27	0.52%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 27

Expense Ratio, Percent

0.52%

^[62]

AssetsNet

$ 9,680,787,851

Holdings Count | Holding

567

Advisory Fees Paid, Amount

$ 10,948,523

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$9,680,787,851
# of Portfolio Investments567
Portfolio Turnover Rate6%
Total Advisory Fees Paid$10,948,523

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	1.8
Utilities	2.2
Energy	2.9
Consumer Staples	4.5
Health Care	8.8
Industrials	8.8
Consumer Discretionary	9.2
Communication Services	9.6
Financials	11.6
Information Technology	37.6

Top Countries

Table Summary
Value	Value
Switzerland	0.1
Netherlands	0.1
United States	99.3

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	7.4
Apple, Inc.	6.5
Alphabet, Inc.	5.8
Microsoft Corp.	4.2
Amazon.com, Inc.	3.6
Broadcom, Inc.	2.7
Micron Technology, Inc.	2.0
Meta Platforms, Inc.	1.9
Tesla, Inc.	1.8
Eli Lilly & Co.	1.5

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000075819

Shareholder Report [Line Items]

Fund Name

MetLife Stock Index Portfolio

Class Name

Class D

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class D	$19	0.37%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 19

Expense Ratio, Percent

0.37%

^[63]

AssetsNet

$ 9,680,787,851

Holdings Count | Holding

567

Advisory Fees Paid, Amount

$ 10,948,523

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$9,680,787,851
# of Portfolio Investments567
Portfolio Turnover Rate6%
Total Advisory Fees Paid$10,948,523

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	1.8
Utilities	2.2
Energy	2.9
Consumer Staples	4.5
Health Care	8.8
Industrials	8.8
Consumer Discretionary	9.2
Communication Services	9.6
Financials	11.6
Information Technology	37.6

Top Countries

Table Summary
Value	Value
Switzerland	0.1
Netherlands	0.1
United States	99.3

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	7.4
Apple, Inc.	6.5
Alphabet, Inc.	5.8
Microsoft Corp.	4.2
Amazon.com, Inc.	3.6
Broadcom, Inc.	2.7
Micron Technology, Inc.	2.0
Meta Platforms, Inc.	1.9
Tesla, Inc.	1.8
Eli Lilly & Co.	1.5

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017820

Shareholder Report [Line Items]

Fund Name

MetLife Stock Index Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$22	0.42%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 22

Expense Ratio, Percent

0.42%

^[64]

AssetsNet

$ 9,680,787,851

Holdings Count | Holding

567

Advisory Fees Paid, Amount

$ 10,948,523

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$9,680,787,851
# of Portfolio Investments567
Portfolio Turnover Rate6%
Total Advisory Fees Paid$10,948,523

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	1.8
Utilities	2.2
Energy	2.9
Consumer Staples	4.5
Health Care	8.8
Industrials	8.8
Consumer Discretionary	9.2
Communication Services	9.6
Financials	11.6
Information Technology	37.6

Top Countries

Table Summary
Value	Value
Switzerland	0.1
Netherlands	0.1
United States	99.3

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	7.4
Apple, Inc.	6.5
Alphabet, Inc.	5.8
Microsoft Corp.	4.2
Amazon.com, Inc.	3.6
Broadcom, Inc.	2.7
Micron Technology, Inc.	2.0
Meta Platforms, Inc.	1.9
Tesla, Inc.	1.8
Eli Lilly & Co.	1.5

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000150812

Shareholder Report [Line Items]

Fund Name

MetLife Stock Index Portfolio

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MetLife Stock Index Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$30	0.57%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.57%

^[65]

AssetsNet

$ 9,680,787,851

Holdings Count | Holding

567

Advisory Fees Paid, Amount

$ 10,948,523

InvestmentCompanyPortfolioTurnover

6.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$9,680,787,851
# of Portfolio Investments567
Portfolio Turnover Rate6%
Total Advisory Fees Paid$10,948,523

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	1.8
Utilities	2.2
Energy	2.9
Consumer Staples	4.5
Health Care	8.8
Industrials	8.8
Consumer Discretionary	9.2
Communication Services	9.6
Financials	11.6
Information Technology	37.6

Top Countries

Table Summary
Value	Value
Switzerland	0.1
Netherlands	0.1
United States	99.3

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	7.4
Apple, Inc.	6.5
Alphabet, Inc.	5.8
Microsoft Corp.	4.2
Amazon.com, Inc.	3.6
Broadcom, Inc.	2.7
Micron Technology, Inc.	2.0
Meta Platforms, Inc.	1.9
Tesla, Inc.	1.8
Eli Lilly & Co.	1.5

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017824

Shareholder Report [Line Items]

Fund Name

MFS<sup style="inset: 1.5px 0px 4px; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 700; grid-area: auto; line-height: 0px; margin: 0px; overflow: visible; position: relative; text-align: left; text-align-last: auto; white-space-collapse: preserve-breaks;">® Total Return Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Total Return Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$32	0.63%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 32

Expense Ratio, Percent

0.63%

^[66]

AssetsNet

$ 566,702,365

Holdings Count | Holding

842

Advisory Fees Paid, Amount

$ 1,578,477

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$566,702,365
# of Portfolio Investments842
Portfolio Turnover Rate23%
Total Advisory Fees Paid$1,578,477

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Bonds	5.2
Federal National Mortgage Association	3.8
U.S. Treasury Notes	3.5
Government National Mortgage Association	2.1
Federal Home Loan Mortgage Corp.	2.0
OCP CLO Ltd.	0.7
LoanCore Issuer Ltd.	0.7
Uniform Mortgage-Backed Security, TBA	0.6
MF1 LLC	0.5
JPMorgan Chase & Co.	0.5

Top 10 Countries

Table Summary
Value	Value
Hong Kong	0.4
Switzerland	0.4
Ireland	0.4
Japan	0.5
Germany	0.8
Canada	1.0
Netherlands	1.2
United Kingdom	2.0
Cayman Islands	3.1
United States	88.4

Asset Allocation

Table Summary
Value	Value
Municipals	0.5
Preferred Stocks	0.6
Convertible Preferred Stocks	0.7
Short-Term Investments	1.3
Asset-Backed Securities	4.2
Non-Agency Mortgage-Backed Securities	4.3
U.S. Treasury & Government Agencies	8.6
Agency Sponsored Mortgage-Backed Securities	9.1
Corporate Bonds & Notes	13.5
Common Stocks	57.7

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Charles Schwab Corp.	2.5
Microsoft Corp.	2.0
Bank of America Corp.	1.9
Pfizer, Inc.	1.8
Medtronic PLC	1.7
Kenvue, Inc.	1.7
Omnicom Group, Inc.	1.7
Becton Dickinson & Co.	1.6
Northern Trust Corp.	1.6
Cigna Group	1.6

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017825

Shareholder Report [Line Items]

Fund Name

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Total Return Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$44	0.88%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 44

Expense Ratio, Percent

0.88%

^[67]

AssetsNet

$ 566,702,365

Holdings Count | Holding

842

Advisory Fees Paid, Amount

$ 1,578,477

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$566,702,365
# of Portfolio Investments842
Portfolio Turnover Rate23%
Total Advisory Fees Paid$1,578,477

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Bonds	5.2
Federal National Mortgage Association	3.8
U.S. Treasury Notes	3.5
Government National Mortgage Association	2.1
Federal Home Loan Mortgage Corp.	2.0
OCP CLO Ltd.	0.7
LoanCore Issuer Ltd.	0.7
Uniform Mortgage-Backed Security, TBA	0.6
MF1 LLC	0.5
JPMorgan Chase & Co.	0.5

Top 10 Countries

Table Summary
Value	Value
Hong Kong	0.4
Switzerland	0.4
Ireland	0.4
Japan	0.5
Germany	0.8
Canada	1.0
Netherlands	1.2
United Kingdom	2.0
Cayman Islands	3.1
United States	88.4

Asset Allocation

Table Summary
Value	Value
Municipals	0.5
Preferred Stocks	0.6
Convertible Preferred Stocks	0.7
Short-Term Investments	1.3
Asset-Backed Securities	4.2
Non-Agency Mortgage-Backed Securities	4.3
U.S. Treasury & Government Agencies	8.6
Agency Sponsored Mortgage-Backed Securities	9.1
Corporate Bonds & Notes	13.5
Common Stocks	57.7

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Charles Schwab Corp.	2.5
Microsoft Corp.	2.0
Bank of America Corp.	1.9
Pfizer, Inc.	1.8
Medtronic PLC	1.7
Kenvue, Inc.	1.7
Omnicom Group, Inc.	1.7
Becton Dickinson & Co.	1.6
Northern Trust Corp.	1.6
Cigna Group	1.6

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017826

Shareholder Report [Line Items]

Fund Name

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Total Return Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$39	0.78%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 39

Expense Ratio, Percent

0.78%

^[68]

AssetsNet

$ 566,702,365

Holdings Count | Holding

842

Advisory Fees Paid, Amount

$ 1,578,477

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$566,702,365
# of Portfolio Investments842
Portfolio Turnover Rate23%
Total Advisory Fees Paid$1,578,477

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Bonds	5.2
Federal National Mortgage Association	3.8
U.S. Treasury Notes	3.5
Government National Mortgage Association	2.1
Federal Home Loan Mortgage Corp.	2.0
OCP CLO Ltd.	0.7
LoanCore Issuer Ltd.	0.7
Uniform Mortgage-Backed Security, TBA	0.6
MF1 LLC	0.5
JPMorgan Chase & Co.	0.5

Top 10 Countries

Table Summary
Value	Value
Hong Kong	0.4
Switzerland	0.4
Ireland	0.4
Japan	0.5
Germany	0.8
Canada	1.0
Netherlands	1.2
United Kingdom	2.0
Cayman Islands	3.1
United States	88.4

Asset Allocation

Table Summary
Value	Value
Municipals	0.5
Preferred Stocks	0.6
Convertible Preferred Stocks	0.7
Short-Term Investments	1.3
Asset-Backed Securities	4.2
Non-Agency Mortgage-Backed Securities	4.3
U.S. Treasury & Government Agencies	8.6
Agency Sponsored Mortgage-Backed Securities	9.1
Corporate Bonds & Notes	13.5
Common Stocks	57.7

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Charles Schwab Corp.	2.5
Microsoft Corp.	2.0
Bank of America Corp.	1.9
Pfizer, Inc.	1.8
Medtronic PLC	1.7
Kenvue, Inc.	1.7
Omnicom Group, Inc.	1.7
Becton Dickinson & Co.	1.6
Northern Trust Corp.	1.6
Cigna Group	1.6

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000030927

Shareholder Report [Line Items]

Fund Name

Class Name

Class F

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Total Return Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class F	$42	0.83%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 42

Expense Ratio, Percent

0.83%

^[69]

AssetsNet

$ 566,702,365

Holdings Count | Holding

842

Advisory Fees Paid, Amount

$ 1,578,477

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$566,702,365
# of Portfolio Investments842
Portfolio Turnover Rate23%
Total Advisory Fees Paid$1,578,477

Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Bonds	5.2
Federal National Mortgage Association	3.8
U.S. Treasury Notes	3.5
Government National Mortgage Association	2.1
Federal Home Loan Mortgage Corp.	2.0
OCP CLO Ltd.	0.7
LoanCore Issuer Ltd.	0.7
Uniform Mortgage-Backed Security, TBA	0.6
MF1 LLC	0.5
JPMorgan Chase & Co.	0.5

Top 10 Countries

Table Summary
Value	Value
Hong Kong	0.4
Switzerland	0.4
Ireland	0.4
Japan	0.5
Germany	0.8
Canada	1.0
Netherlands	1.2
United Kingdom	2.0
Cayman Islands	3.1
United States	88.4

Asset Allocation

Table Summary
Value	Value
Municipals	0.5
Preferred Stocks	0.6
Convertible Preferred Stocks	0.7
Short-Term Investments	1.3
Asset-Backed Securities	4.2
Non-Agency Mortgage-Backed Securities	4.3
U.S. Treasury & Government Agencies	8.6
Agency Sponsored Mortgage-Backed Securities	9.1
Corporate Bonds & Notes	13.5
Common Stocks	57.7

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Charles Schwab Corp.	2.5
Microsoft Corp.	2.0
Bank of America Corp.	1.9
Pfizer, Inc.	1.8
Medtronic PLC	1.7
Kenvue, Inc.	1.7
Omnicom Group, Inc.	1.7
Becton Dickinson & Co.	1.6
Northern Trust Corp.	1.6
Cigna Group	1.6

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017790

Shareholder Report [Line Items]

Fund Name

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Value Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$30	0.58%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 30

Expense Ratio, Percent

0.58%

^[70]

AssetsNet

$ 2,594,663,118

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,201,246

InvestmentCompanyPortfolioTurnover

19.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,594,663,118
# of Portfolio Investments88
Portfolio Turnover Rate19%
Total Advisory Fees Paid$7,201,246

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	0.9
Real Estate	1.5
Consumer Staples	4.0
Energy	5.6
Utilities	8.0
Consumer Discretionary	8.3
Health Care	12.8
Information Technology	15.8
Industrials	16.1
Financials	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.1
Netherlands	1.5
United States	96.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Amazon.com, Inc.	5.1
JPMorgan Chase & Co.	4.0
Microsoft Corp.	3.4
KLA Corp.	3.2
Apple, Inc.	2.9
Johnson & Johnson	2.6
Cigna Group	2.6
Morgan Stanley	2.2
Analog Devices, Inc.	2.2
RTX Corp.	2.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017791

Shareholder Report [Line Items]

Fund Name

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Value Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$43	0.83%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 43

Expense Ratio, Percent

0.83%

^[71]

AssetsNet

$ 2,594,663,118

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,201,246

InvestmentCompanyPortfolioTurnover

19.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,594,663,118
# of Portfolio Investments88
Portfolio Turnover Rate19%
Total Advisory Fees Paid$7,201,246

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	0.9
Real Estate	1.5
Consumer Staples	4.0
Energy	5.6
Utilities	8.0
Consumer Discretionary	8.3
Health Care	12.8
Information Technology	15.8
Industrials	16.1
Financials	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.1
Netherlands	1.5
United States	96.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Amazon.com, Inc.	5.1
JPMorgan Chase & Co.	4.0
Microsoft Corp.	3.4
KLA Corp.	3.2
Apple, Inc.	2.9
Johnson & Johnson	2.6
Cigna Group	2.6
Morgan Stanley	2.2
Analog Devices, Inc.	2.2
RTX Corp.	2.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000124380

Shareholder Report [Line Items]

Fund Name

Class Name

Class D

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Value Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class D	$35	0.68%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.68%

^[72]

AssetsNet

$ 2,594,663,118

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,201,246

InvestmentCompanyPortfolioTurnover

19.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,594,663,118
# of Portfolio Investments88
Portfolio Turnover Rate19%
Total Advisory Fees Paid$7,201,246

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	0.9
Real Estate	1.5
Consumer Staples	4.0
Energy	5.6
Utilities	8.0
Consumer Discretionary	8.3
Health Care	12.8
Information Technology	15.8
Industrials	16.1
Financials	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.1
Netherlands	1.5
United States	96.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Amazon.com, Inc.	5.1
JPMorgan Chase & Co.	4.0
Microsoft Corp.	3.4
KLA Corp.	3.2
Apple, Inc.	2.9
Johnson & Johnson	2.6
Cigna Group	2.6
Morgan Stanley	2.2
Analog Devices, Inc.	2.2
RTX Corp.	2.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017792

Shareholder Report [Line Items]

Fund Name

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the MFS^® Value Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$37	0.73%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.73%

^[73]

AssetsNet

$ 2,594,663,118

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 7,201,246

InvestmentCompanyPortfolioTurnover

19.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,594,663,118
# of Portfolio Investments88
Portfolio Turnover Rate19%
Total Advisory Fees Paid$7,201,246

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Materials	0.9
Real Estate	1.5
Consumer Staples	4.0
Energy	5.6
Utilities	8.0
Consumer Discretionary	8.3
Health Care	12.8
Information Technology	15.8
Industrials	16.1
Financials	25.0

Top Countries

Table Summary
Value	Value
United Kingdom	1.1
Netherlands	1.5
United States	96.1

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Amazon.com, Inc.	5.1
JPMorgan Chase & Co.	4.0
Microsoft Corp.	3.4
KLA Corp.	3.2
Apple, Inc.	2.9
Johnson & Johnson	2.6
Cigna Group	2.6
Morgan Stanley	2.2
Analog Devices, Inc.	2.2
RTX Corp.	2.2

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017867

Shareholder Report [Line Items]

Fund Name

Neuberger Berman Genesis Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Neuberger Berman Genesis Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$44	0.82%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 44

Expense Ratio, Percent

0.82%

^[74]

AssetsNet

$ 782,878,405

Holdings Count | Holding

104

Advisory Fees Paid, Amount

$ 2,987,097

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$782,878,405
# of Portfolio Investments104
Portfolio Turnover Rate23%
Total Advisory Fees Paid$2,987,097

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.1
Real Estate	2.1
Utilities	5.7
Energy	5.8
Materials	6.0
Consumer Discretionary	6.7
Health Care	8.9
Information Technology	13.5
Financials	19.2
Industrials	27.5

Top Countries

Table Summary
Value	Value
Italy	0.7
Canada	2.1
United States	94.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Valmont Industries, Inc.	2.0
MKS, Inc.	1.8
White Mountains Insurance Group Ltd.	1.7
Community Financial System, Inc.	1.7
UMB Financial Corp.	1.7
Prosperity Bancshares, Inc.	1.6
Littelfuse, Inc.	1.5
American States Water Co.	1.5
Haemonetics Corp.	1.5
Gates Industrial Corp. PLC	1.4

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017868

Shareholder Report [Line Items]

Fund Name

Neuberger Berman Genesis Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Neuberger Berman Genesis Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$57	1.07%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 57

Expense Ratio, Percent

1.07%

^[75]

AssetsNet

$ 782,878,405

Holdings Count | Holding

104

Advisory Fees Paid, Amount

$ 2,987,097

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$782,878,405
# of Portfolio Investments104
Portfolio Turnover Rate23%
Total Advisory Fees Paid$2,987,097

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.1
Real Estate	2.1
Utilities	5.7
Energy	5.8
Materials	6.0
Consumer Discretionary	6.7
Health Care	8.9
Information Technology	13.5
Financials	19.2
Industrials	27.5

Top Countries

Table Summary
Value	Value
Italy	0.7
Canada	2.1
United States	94.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Valmont Industries, Inc.	2.0
MKS, Inc.	1.8
White Mountains Insurance Group Ltd.	1.7
Community Financial System, Inc.	1.7
UMB Financial Corp.	1.7
Prosperity Bancshares, Inc.	1.6
Littelfuse, Inc.	1.5
American States Water Co.	1.5
Haemonetics Corp.	1.5
Gates Industrial Corp. PLC	1.4

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017869

Shareholder Report [Line Items]

Fund Name

Neuberger Berman Genesis Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Neuberger Berman Genesis Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$52	0.97%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 52

Expense Ratio, Percent

0.97%

^[76]

AssetsNet

$ 782,878,405

Holdings Count | Holding

104

Advisory Fees Paid, Amount

$ 2,987,097

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$782,878,405
# of Portfolio Investments104
Portfolio Turnover Rate23%
Total Advisory Fees Paid$2,987,097

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Communication Services	2.1
Real Estate	2.1
Utilities	5.7
Energy	5.8
Materials	6.0
Consumer Discretionary	6.7
Health Care	8.9
Information Technology	13.5
Financials	19.2
Industrials	27.5

Top Countries

Table Summary
Value	Value
Italy	0.7
Canada	2.1
United States	94.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Valmont Industries, Inc.	2.0
MKS, Inc.	1.8
White Mountains Insurance Group Ltd.	1.7
Community Financial System, Inc.	1.7
UMB Financial Corp.	1.7
Prosperity Bancshares, Inc.	1.6
Littelfuse, Inc.	1.5
American States Water Co.	1.5
Haemonetics Corp.	1.5
Gates Industrial Corp. PLC	1.4

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017848

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Large Cap Growth Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Large Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$27	0.54%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 27

Expense Ratio, Percent

0.54%

^[77]

AssetsNet

$ 2,243,111,000

Holdings Count | Holding

115

Advisory Fees Paid, Amount

$ 5,533,454

InvestmentCompanyPortfolioTurnover

31.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,243,111,000
# of Portfolio Investments115
Portfolio Turnover Rate31%
Total Advisory Fees Paid$5,533,454

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.2
Real Estate	0.6
Materials	1.0
Financials	5.4
Health Care	6.4
Consumer Discretionary	8.1
Communication Services	13.8
Industrials	14.9
Information Technology	48.8

Top Countries

Table Summary
Value	Value
Thailand	0.2
Italy	0.3
Singapore	0.3
Brazil	0.3
Canada	0.6
Taiwan	1.0
Netherlands	1.4
United States	95.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.8
Alphabet, Inc.	7.8
Apple, Inc.	5.8
Broadcom, Inc.	5.3
Microsoft Corp.	4.1
Eli Lilly & Co.	3.4
Meta Platforms, Inc.	3.2
Caterpillar, Inc.	3.0
Tesla, Inc.	2.9
Advanced Micro Devices, Inc.	2.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017849

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Large Cap Growth Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Large Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$40	0.79%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 40

Expense Ratio, Percent

0.79%

^[78]

AssetsNet

$ 2,243,111,000

Holdings Count | Holding

115

Advisory Fees Paid, Amount

$ 5,533,454

InvestmentCompanyPortfolioTurnover

31.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,243,111,000
# of Portfolio Investments115
Portfolio Turnover Rate31%
Total Advisory Fees Paid$5,533,454

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.2
Real Estate	0.6
Materials	1.0
Financials	5.4
Health Care	6.4
Consumer Discretionary	8.1
Communication Services	13.8
Industrials	14.9
Information Technology	48.8

Top Countries

Table Summary
Value	Value
Thailand	0.2
Italy	0.3
Singapore	0.3
Brazil	0.3
Canada	0.6
Taiwan	1.0
Netherlands	1.4
United States	95.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.8
Alphabet, Inc.	7.8
Apple, Inc.	5.8
Broadcom, Inc.	5.3
Microsoft Corp.	4.1
Eli Lilly & Co.	3.4
Meta Platforms, Inc.	3.2
Caterpillar, Inc.	3.0
Tesla, Inc.	2.9
Advanced Micro Devices, Inc.	2.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017850

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Large Cap Growth Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Large Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$35	0.69%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.69%

^[79]

AssetsNet

$ 2,243,111,000

Holdings Count | Holding

115

Advisory Fees Paid, Amount

$ 5,533,454

InvestmentCompanyPortfolioTurnover

31.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$2,243,111,000
# of Portfolio Investments115
Portfolio Turnover Rate31%
Total Advisory Fees Paid$5,533,454

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Consumer Staples	0.2
Real Estate	0.6
Materials	1.0
Financials	5.4
Health Care	6.4
Consumer Discretionary	8.1
Communication Services	13.8
Industrials	14.9
Information Technology	48.8

Top Countries

Table Summary
Value	Value
Thailand	0.2
Italy	0.3
Singapore	0.3
Brazil	0.3
Canada	0.6
Taiwan	1.0
Netherlands	1.4
United States	95.2

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
NVIDIA Corp.	13.8
Alphabet, Inc.	7.8
Apple, Inc.	5.8
Broadcom, Inc.	5.3
Microsoft Corp.	4.1
Eli Lilly & Co.	3.4
Meta Platforms, Inc.	3.2
Caterpillar, Inc.	3.0
Tesla, Inc.	2.9
Advanced Micro Devices, Inc.	2.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017851

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Small Cap Growth Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$27	0.49%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 27

Expense Ratio, Percent

0.49%

^[80]

AssetsNet

$ 1,127,006,225

Holdings Count | Holding

366

Advisory Fees Paid, Amount

$ 2,484,452

InvestmentCompanyPortfolioTurnover

45.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,127,006,225
# of Portfolio Investments366
Portfolio Turnover Rate45%
Total Advisory Fees Paid$2,484,452

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Consumer Staples	1.0
Communication Services	1.1
Real Estate	1.9
Materials	3.8
Energy	4.7
Consumer Discretionary	8.3
Financials	9.1
Industrials	19.8
Information Technology	22.6
Health Care	27.4

Top 10 Countries

Table Summary
Value	Value
Germany	0.2
Denmark	0.2
Thailand	0.2
Finland	0.2
Costa Rica	0.3
Israel	0.6
Puerto Rico	1.4
United Kingdom	1.4
Canada	2.1
United States	93.0

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
StoneX Group, Inc.	1.0
BrightSpring Health Services, Inc.	1.0
InterDigital, Inc.	1.0
Moog, Inc.	1.0
Bel Fuse, Inc.	0.9
ESCO Technologies, Inc.	0.8
Belden, Inc.	0.8
Marex Group PLC	0.8
FirstCash Holdings, Inc.	0.8
Federal Signal Corp.	0.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017852

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Small Cap Growth Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$41	0.74%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 41

Expense Ratio, Percent

0.74%

^[81]

AssetsNet

$ 1,127,006,225

Holdings Count | Holding

366

Advisory Fees Paid, Amount

$ 2,484,452

InvestmentCompanyPortfolioTurnover

45.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,127,006,225
# of Portfolio Investments366
Portfolio Turnover Rate45%
Total Advisory Fees Paid$2,484,452

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Consumer Staples	1.0
Communication Services	1.1
Real Estate	1.9
Materials	3.8
Energy	4.7
Consumer Discretionary	8.3
Financials	9.1
Industrials	19.8
Information Technology	22.6
Health Care	27.4

Top 10 Countries

Table Summary
Value	Value
Germany	0.2
Denmark	0.2
Thailand	0.2
Finland	0.2
Costa Rica	0.3
Israel	0.6
Puerto Rico	1.4
United Kingdom	1.4
Canada	2.1
United States	93.0

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
StoneX Group, Inc.	1.0
BrightSpring Health Services, Inc.	1.0
InterDigital, Inc.	1.0
Moog, Inc.	1.0
Bel Fuse, Inc.	0.9
ESCO Technologies, Inc.	0.8
Belden, Inc.	0.8
Marex Group PLC	0.8
FirstCash Holdings, Inc.	0.8
Federal Signal Corp.	0.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017853

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Small Cap Growth Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$35	0.64%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.64%

^[82]

AssetsNet

$ 1,127,006,225

Holdings Count | Holding

366

Advisory Fees Paid, Amount

$ 2,484,452

InvestmentCompanyPortfolioTurnover

45.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,127,006,225
# of Portfolio Investments366
Portfolio Turnover Rate45%
Total Advisory Fees Paid$2,484,452

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Consumer Staples	1.0
Communication Services	1.1
Real Estate	1.9
Materials	3.8
Energy	4.7
Consumer Discretionary	8.3
Financials	9.1
Industrials	19.8
Information Technology	22.6
Health Care	27.4

Top 10 Countries

Table Summary
Value	Value
Germany	0.2
Denmark	0.2
Thailand	0.2
Finland	0.2
Costa Rica	0.3
Israel	0.6
Puerto Rico	1.4
United Kingdom	1.4
Canada	2.1
United States	93.0

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
StoneX Group, Inc.	1.0
BrightSpring Health Services, Inc.	1.0
InterDigital, Inc.	1.0
Moog, Inc.	1.0
Bel Fuse, Inc.	0.9
ESCO Technologies, Inc.	0.8
Belden, Inc.	0.8
Marex Group PLC	0.8
FirstCash Holdings, Inc.	0.8
Federal Signal Corp.	0.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000150813

Shareholder Report [Line Items]

Fund Name

T. Rowe Price Small Cap Growth Portfolio

Class Name

Class G

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the T. Rowe Price Small Cap Growth Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class G	$43	0.79%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 43

Expense Ratio, Percent

0.79%

^[83]

AssetsNet

$ 1,127,006,225

Holdings Count | Holding

366

Advisory Fees Paid, Amount

$ 2,484,452

InvestmentCompanyPortfolioTurnover

45.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,127,006,225
# of Portfolio Investments366
Portfolio Turnover Rate45%
Total Advisory Fees Paid$2,484,452

Holdings [Text Block]

Top 10 Sectors

Table Summary
Value	Value
Consumer Staples	1.0
Communication Services	1.1
Real Estate	1.9
Materials	3.8
Energy	4.7
Consumer Discretionary	8.3
Financials	9.1
Industrials	19.8
Information Technology	22.6
Health Care	27.4

Top 10 Countries

Table Summary
Value	Value
Germany	0.2
Denmark	0.2
Thailand	0.2
Finland	0.2
Costa Rica	0.3
Israel	0.6
Puerto Rico	1.4
United Kingdom	1.4
Canada	2.1
United States	93.0

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
StoneX Group, Inc.	1.0
BrightSpring Health Services, Inc.	1.0
InterDigital, Inc.	1.0
Moog, Inc.	1.0
Bel Fuse, Inc.	0.9
ESCO Technologies, Inc.	0.8
Belden, Inc.	0.8
Marex Group PLC	0.8
FirstCash Holdings, Inc.	0.8
Federal Signal Corp.	0.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000069951

Shareholder Report [Line Items]

Fund Name

VanEck Global Natural Resources Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the VanEck Global Natural Resources Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$39	0.77%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 39

Expense Ratio, Percent

0.77%

^[84]

AssetsNet

$ 670,824,935

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,693,538

InvestmentCompanyPortfolioTurnover

65.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$670,824,935
# of Portfolio Investments62
Portfolio Turnover Rate65%
Total Advisory Fees Paid$2,693,538

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Industrials	3.0
Consumer Staples	5.8
Energy	40.0
Materials	49.3

Top Countries

Table Summary
Value	Value
Luxembourg	1.0
United Kingdom	1.1
Turkey	1.3
Zambia	1.5
Australia	3.2
South Africa	3.6
Canada	23.8
United States	62.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Nutrien Ltd.	4.9
Diamondback Energy, Inc.	4.1
Canadian Natural Resources Ltd.	4.1
Ovintiv, Inc.	4.0
CRH PLC	3.7
BP PLC	3.2
Glencore PLC	3.2
Core Natural Resources, Inc.	3.0
Hudbay Minerals, Inc.	3.0
Expand Energy Corp.	2.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000069952

Shareholder Report [Line Items]

Fund Name

VanEck Global Natural Resources Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the VanEck Global Natural Resources Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$52	1.02%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 52

Expense Ratio, Percent

1.02%

^[85]

AssetsNet

$ 670,824,935

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 2,693,538

InvestmentCompanyPortfolioTurnover

65.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$670,824,935
# of Portfolio Investments62
Portfolio Turnover Rate65%
Total Advisory Fees Paid$2,693,538

Holdings [Text Block]

Top Sectors

Table Summary
Value	Value
Industrials	3.0
Consumer Staples	5.8
Energy	40.0
Materials	49.3

Top Countries

Table Summary
Value	Value
Luxembourg	1.0
United Kingdom	1.1
Turkey	1.3
Zambia	1.5
Australia	3.2
South Africa	3.6
Canada	23.8
United States	62.6

Largest Holdings [Text Block]

Top 10 Equity Holdings

Table Summary
Nutrien Ltd.	4.9
Diamondback Energy, Inc.	4.1
Canadian Natural Resources Ltd.	4.1
Ovintiv, Inc.	4.0
CRH PLC	3.7
BP PLC	3.2
Glencore PLC	3.2
Core Natural Resources, Inc.	3.0
Hudbay Minerals, Inc.	3.0
Expand Energy Corp.	2.8

Material Fund Change [Text Block]

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017842

Shareholder Report [Line Items]

Fund Name

Western Asset Management Strategic Bond Opportunities Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Western Asset Management Strategic Bond Opportunities Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$29	0.58%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.58%

^[86]

AssetsNet

$ 1,779,810,304

Holdings Count | Holding

813

Advisory Fees Paid, Amount

$ 4,759,710

InvestmentCompanyPortfolioTurnover

32.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,779,810,304
# of Portfolio Investments813
Portfolio Turnover Rate32%
Total Advisory Fees Paid$4,759,710

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.0^{Footnote Reference*}
Rights	0.0^{Footnote Reference*}
Common Stocks	0.1
Short-Term Investments	0.1
U.S. Treasury & Government Agencies	0.1
Convertible Preferred Stocks	0.3
Agency Sponsored Mortgage-Backed Securities	4.5
Foreign Government	4.7
Asset-Backed Securities	10.0
Floating Rate Loans	13.2
Non-Agency Mortgage-Backed Securities	14.3
Corporate Bonds & Notes	51.0

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
Federal National Mortgage Association Connecticut Avenue Securities Trust	2.2
Mcclatchy Media Co. LLC	2.2
BX Commercial Mortgage Trust	1.5
Federal Home Loan Mortgage Corp. STACR REMICS Trust	1.1
Venture Global Plaquemines LNG LLC	1.0
First Quantum Minerals Ltd.	0.8
CHS/Community Health Systems, Inc.	0.7
NRG Energy, Inc.	0.7
Inter-American Development Bank	0.7
CSMC Trust	0.7

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017843

Shareholder Report [Line Items]

Fund Name

Western Asset Management Strategic Bond Opportunities Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$42	0.83%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 42

Expense Ratio, Percent

0.83%

^[87]

AssetsNet

$ 1,779,810,304

Holdings Count | Holding

813

Advisory Fees Paid, Amount

$ 4,759,710

InvestmentCompanyPortfolioTurnover

32.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,779,810,304
# of Portfolio Investments813
Portfolio Turnover Rate32%
Total Advisory Fees Paid$4,759,710

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.0^{Footnote Reference*}
Rights	0.0^{Footnote Reference*}
Common Stocks	0.1
Short-Term Investments	0.1
U.S. Treasury & Government Agencies	0.1
Convertible Preferred Stocks	0.3
Agency Sponsored Mortgage-Backed Securities	4.5
Foreign Government	4.7
Asset-Backed Securities	10.0
Floating Rate Loans	13.2
Non-Agency Mortgage-Backed Securities	14.3
Corporate Bonds & Notes	51.0

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
Federal National Mortgage Association Connecticut Avenue Securities Trust	2.2
Mcclatchy Media Co. LLC	2.2
BX Commercial Mortgage Trust	1.5
Federal Home Loan Mortgage Corp. STACR REMICS Trust	1.1
Venture Global Plaquemines LNG LLC	1.0
First Quantum Minerals Ltd.	0.8
CHS/Community Health Systems, Inc.	0.7
NRG Energy, Inc.	0.7
Inter-American Development Bank	0.7
CSMC Trust	0.7

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017844

Shareholder Report [Line Items]

Fund Name

Western Asset Management Strategic Bond Opportunities Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$37	0.73%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.73%

^[88]

AssetsNet

$ 1,779,810,304

Holdings Count | Holding

813

Advisory Fees Paid, Amount

$ 4,759,710

InvestmentCompanyPortfolioTurnover

32.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,779,810,304
# of Portfolio Investments813
Portfolio Turnover Rate32%
Total Advisory Fees Paid$4,759,710

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Convertible Bonds	0.0^{Footnote Reference*}
Rights	0.0^{Footnote Reference*}
Common Stocks	0.1
Short-Term Investments	0.1
U.S. Treasury & Government Agencies	0.1
Convertible Preferred Stocks	0.3
Agency Sponsored Mortgage-Backed Securities	4.5
Foreign Government	4.7
Asset-Backed Securities	10.0
Floating Rate Loans	13.2
Non-Agency Mortgage-Backed Securities	14.3
Corporate Bonds & Notes	51.0

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
Federal National Mortgage Association Connecticut Avenue Securities Trust	2.2
Mcclatchy Media Co. LLC	2.2
BX Commercial Mortgage Trust	1.5
Federal Home Loan Mortgage Corp. STACR REMICS Trust	1.1
Venture Global Plaquemines LNG LLC	1.0
First Quantum Minerals Ltd.	0.8
CHS/Community Health Systems, Inc.	0.7
NRG Energy, Inc.	0.7
Inter-American Development Bank	0.7
CSMC Trust	0.7

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017845

Shareholder Report [Line Items]

Fund Name

Western Asset Management U.S. Government Portfolio

Class Name

Class A

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Western Asset Management U.S. Government Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class A	$25	0.51%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 25

Expense Ratio, Percent

0.51%

^[89]

AssetsNet

$ 1,192,822,949

Holdings Count | Holding

735

Advisory Fees Paid, Amount

$ 2,811,720

InvestmentCompanyPortfolioTurnover

86.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,192,822,949
# of Portfolio Investments735
Portfolio Turnover Rate86%
Total Advisory Fees Paid$2,811,720

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Asset-Backed Securities	0.0^{Footnote Reference*}
Corporate Bonds & Notes	0.8
Short-Term Investments	1.7
Foreign Government	3.1
Non-Agency Mortgage-Backed Securities	4.1
Agency Sponsored Mortgage-Backed Securities	35.2
U.S. Treasury & Government Agencies	59.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	26.3
Federal National Mortgage Association	12.1
Federal Home Loan Mortgage Corp.	10.4
Resolution Funding Corp. Principal STRIPS	8.6
Federal Home Loan Banks	5.6
Government National Mortgage Association	5.6
Federal Farm Credit Banks Funding Corp.	4.1
Uniform Mortgage-Backed Security, TBA	3.0
Tennessee Valley Authority	3.0
Resolution Funding Corp. Interest STRIPS	2.2

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017846

Shareholder Report [Line Items]

Fund Name

Western Asset Management U.S. Government Portfolio

Class Name

Class B

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Western Asset Management U.S. Government Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class B	$38	0.76%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.76%

^[90]

AssetsNet

$ 1,192,822,949

Holdings Count | Holding

735

Advisory Fees Paid, Amount

$ 2,811,720

InvestmentCompanyPortfolioTurnover

86.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,192,822,949
# of Portfolio Investments735
Portfolio Turnover Rate86%
Total Advisory Fees Paid$2,811,720

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Asset-Backed Securities	0.0^{Footnote Reference*}
Corporate Bonds & Notes	0.8
Short-Term Investments	1.7
Foreign Government	3.1
Non-Agency Mortgage-Backed Securities	4.1
Agency Sponsored Mortgage-Backed Securities	35.2
U.S. Treasury & Government Agencies	59.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	26.3
Federal National Mortgage Association	12.1
Federal Home Loan Mortgage Corp.	10.4
Resolution Funding Corp. Principal STRIPS	8.6
Federal Home Loan Banks	5.6
Government National Mortgage Association	5.6
Federal Farm Credit Banks Funding Corp.	4.1
Uniform Mortgage-Backed Security, TBA	3.0
Tennessee Valley Authority	3.0
Resolution Funding Corp. Interest STRIPS	2.2

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

C000017847

Shareholder Report [Line Items]

Fund Name

Western Asset Management U.S. Government Portfolio

Class Name

Class E

No Trading Symbol [Flag]

true

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Western Asset Management U.S. Government Portfolio (the "Portfolio") for the period of January 1, 2026 to June 30, 2026.

Additional Information [Text Block]

You can find additional information about the Portfolio at https://dfinview.com/BHFT. You can also request this information by contacting us at 1-888-243-1956.

Additional Information Phone Number

1-888-243-1956

Additional Information Website

Expenses [Text Block]

What were the Portfolio costs for last six months?

This example shows the expenses you would have paid over the reporting period 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
Class E	$33	0.66%^{Footnote Reference*}

Footnote	Description
Footnote^*	Annualized.

Expenses Paid, Amount

$ 33

Expense Ratio, Percent

0.66%

^[91]

AssetsNet

$ 1,192,822,949

Holdings Count | Holding

735

Advisory Fees Paid, Amount

$ 2,811,720

InvestmentCompanyPortfolioTurnover

86.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets$1,192,822,949
# of Portfolio Investments735
Portfolio Turnover Rate86%
Total Advisory Fees Paid$2,811,720

Holdings [Text Block]

Asset Allocation

Table Summary
Value	Value
Asset-Backed Securities	0.0^{Footnote Reference*}
Corporate Bonds & Notes	0.8
Short-Term Investments	1.7
Foreign Government	3.1
Non-Agency Mortgage-Backed Securities	4.1
Agency Sponsored Mortgage-Backed Securities	35.2
U.S. Treasury & Government Agencies	59.1

Footnote	Description
Footnote^*	Amount rounds to less than 0.1%

Largest Holdings [Text Block]

Top 10 Fixed Income Issuers

Table Summary
U.S. Treasury Notes	26.3
Federal National Mortgage Association	12.1
Federal Home Loan Mortgage Corp.	10.4
Resolution Funding Corp. Principal STRIPS	8.6
Federal Home Loan Banks	5.6
Government National Mortgage Association	5.6
Federal Farm Credit Banks Funding Corp.	4.1
Uniform Mortgage-Backed Security, TBA	3.0
Tennessee Valley Authority	3.0
Resolution Funding Corp. Interest STRIPS	2.2

Updated Prospectus Phone Number

1-888-243-1956

Updated Prospectus Web Address

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