v3.26.1
Brighthouse Templeton International Bond Portfolio Investment Risks - Brighthouse Templeton International Bond Portfolio
Dec. 31, 2025
Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Market Risk.  The Portfolio’s share price can fall because of, among other things, a decline in the market as a whole, deterioration in the prospects for a particular industry or company, changes in general economic conditions, such as prevailing interest rates or investor sentiment, or other factors including terrorism, war, natural disasters and the spread of infectious illness including epidemics or pandemics. In addition, unexpected political, regulatory, trade and diplomatic events within the United States and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Significant disruptions to the financial markets could adversely affect the liquidity and volatility of securities held by the Portfolio.
Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Foreign Investment Risk.  Investments in foreign securities, whether direct or indirect, tend to be more volatile and less liquid than investments in U.S. securities because, among other things, they involve risks relating to political, social, economic and other developments abroad, as well as risks resulting from differences between the regulations and reporting standards and practices to which U.S. and foreign issuers are subject. To the extent foreign securities are denominated in foreign currencies, their values may be adversely affected by changes in currency exchange rates. To the extent the Portfolio invests in foreign sovereign debt securities, it is subject to additional risks.
Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Emerging Markets Risk.  In addition to all of the risks of investing in foreign developed markets, emerging market securities involve risks attendant to less mature and stable governments and economies, lower trading volume, trading suspension, security price volatility, proceeds repatriation restrictions, withholding and other taxes, some of which may be confiscatory, inflation, deflation, currency devaluation and adverse government regulations of industries or markets. As a result of these risks, the prices of emerging market securities tend to be more volatile than the securities of issuers located in developed markets.
Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Interest Rate Risk.  The value of the Portfolio’s investments in fixed income securities may decline when prevailing interest rates rise or increase when interest rates fall. The longer a security’s maturity or duration, the greater its value will change in response to changes in interest rates. The interest earned on the Portfolio’s investments in fixed income securities may decline when prevailing interest rates fall. During periods of very low or negative interest rates, the Portfolio  may be unable to maintain positive returns or pay dividends to Portfolio shareholders. Additionally, under certain market conditions in which interest rates are low or negative, the Portfolio  may have a very low, or even negative yield. A low or negative yield would cause the Portfolio  to lose money and the net asset value of the Portfolio’s shares to decline in certain conditions and over certain time periods. Changes in prevailing interest rates, particularly sudden changes, may also increase the level of volatility in fixed income and other markets, increase redemptions in the Portfolio’s shares and reduce the liquidity of the Portfolio’s debt securities and other income-producing holdings. Changes in interest rate levels are caused by a variety of factors, such as central bank monetary policies, inflation rates, and general economic and market conditions.
Credit and Counterparty Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Credit and Counterparty Risk.  The value of the Portfolio’s investments may be adversely affected if a security’s credit rating is downgraded or an issuer of an investment held by the Portfolio fails to pay an obligation on a timely basis, otherwise defaults or is perceived by other investors to be less creditworthy. If a counterparty to a derivatives or other transaction with the Portfolio files for bankruptcy, becomes insolvent, or otherwise becomes unable or unwilling to honor its obligation to the Portfolio, the Portfolio may experience significant losses or delays in realizing income on or recovering collateral and may lose all or a part of the income from the transaction.
High Yield Debt Security Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] High Yield Debt Security Risk.  High yield debt securities, or “junk” bonds, may be more susceptible to market risk and credit and counterparty risk than investment grade debt securities because issuers of high yield debt securities are less secure financially and their securities are more sensitive to downturns in the economy. In addition, the secondary market for high yield debt securities may not be as liquid as that for higher rated debt securities. High-yield debt securities range from those for which the prospect for repayment of principal and interest is predominantly speculative to those which are currently in default on principal or interest payments or whose issuers are in bankruptcy.
Credit Default Swap Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swap Risk.  Credit default swaps may increase credit and counterparty risk (depending on whether the Portfolio is the buyer or seller of the swaps), and they may be illiquid. Credit default swaps also may be difficult to value, especially in the event of market disruptions. Credit default swap transactions in which the Portfolio is the seller may require that the Portfolio sell portfolio securities when it is not advantageous to do so in order to satisfy its obligations.
Short Sale and Short Position Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Short Sale and Short Position Risk.  The Portfolio will incur a loss from a short sale or short position if the value of the security sold short or the reference instrument, in the case of a short position, increases after the time the Portfolio entered into the short sale or short position. In addition, when the Portfolio engages in short sales, a lender may request, or market conditions may dictate, that securities sold short be returned to the lender on short notice, and the Portfolio may have to buy the securities sold short at an unfavorable price. Engaging in a short sale or short position may cause the Portfolio to lose more money than the actual cost of the short sale or short position and the Portfolio’s potential losses may be unlimited if the Portfolio does not own the security sold short or the reference instrument and it is unable to close out of the short sale or short position. Any gain from a short sale or short position will be offset in whole or in part by the transaction costs associated with the short sale or short position. Short sales and short positions generally involve a form of leverage, which can exaggerate a Portfolio’s losses.
TIPS and Inflation Linked Bonds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] TIPS and Inflation-Linked Bonds Risk.  The value of inflation-protected securities generally fluctuates in response to changes in real interest rates, which are in turn tied to the relationship between nominal interest rates and the rate of inflation. Therefore, if inflation were to rise at a faster rate than nominal interest rates, real interest rates would decline, leading to an increase in the value of inflation-protected securities. In contrast, if nominal interest rates increased at a faster rate than inflation, real interest rates would rise, leading to a decrease in the value of inflation-protected securities. When real interest rates are rising faster than nominal interest rates, inflation-indexed bonds, including Treasury Inflation Protected Securities, may experience greater losses than other fixed income securities with similar durations. The inflation-protected securities markets are generally much smaller and less liquid than the markets for nominal bonds from the same issuers and as such can suffer losses during times of economic stress or illiquidity.
Interest Rate Swap Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Interest Rate Swap Risk.  The risk of interest rate swaps includes changes in market conditions that may affect the value of the contract or the cash flows, and the possible inability or unwillingness of the counterparty to fulfill its obligations under the agreement. Certain interest rate swap arrangements also involve the risk that they do not fully offset adverse changes in interest rates. Interest rate swaps may be illiquid and may be difficult to trade or value, especially in the event of market disruptions. Under certain market conditions, the investment performance of the Portfolio may be less favorable than it would have been if the Portfolio had not used the swap agreement.
Forward and Futures Contract Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Forward and Futures Contract Risk.  The successful use of forward and futures contracts will depend upon the Subadviser’s skill and experience with respect to such instruments and are subject to special risk considerations. The primary risks associated with the use of forward and futures contracts include (i) the imperfect correlation between the change in market value of the instruments held by the Portfolio and the price of the forward or futures contract; (ii) possible lack of a liquid market for a forward or futures contract and the resulting inability to close a forward or futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) the Subadviser’s inability to predict correctly the direction of securities prices, interest rates, currency exchange rates and other economic factors; (v) the possibility that the counterparty will default in the performance of its obligations; (vi) if the Portfolio has insufficient cash, it may have to sell securities to meet daily variation margin requirements, and the Portfolio may have to sell securities at a time when it is disadvantageous to do so; (vii) the possibility that the Portfolio may be delayed or prevented from recovering margin or other amounts deposited with a futures commission merchant or clearinghouse; (viii) the possibility that position or trading limits will preclude the Subadviser from taking positions in certain futures contracts on behalf of the Portfolio; and (ix) the risks typically associated with foreign investments to the extent the Portfolio invests in derivatives traded on markets outside the United States.
Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Derivatives Risk.  The Portfolio may invest in derivatives to obtain investment exposure, enhance return or “hedge” or protect its assets from an unfavorable shift in the value or rate of a reference instrument or asset. Derivatives can be highly volatile and can significantly increase the Portfolio’s exposure to market risk, credit and counterparty risk and other risks. Derivatives may be illiquid and difficult to value and can involve risks in addition to, and potentially greater than, the risks of the underlying reference instrument. Because of their complex nature, some derivatives may not perform as intended. As a result, the Portfolio may not realize the anticipated benefits from a derivative it holds or it may realize losses. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivative transactions may create investment leverage, which increases the Portfolio’s volatility and may require the Portfolio to liquidate portfolio securities when it is not advantageous to do so. Government regulation of derivative instruments may limit or prevent the Portfolio from using such instruments as part of its investment strategies, which could adversely affect the Portfolio.
Focused Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Focused Investment Risk.  Substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, country, region, group of countries, asset class or sector make the Portfolio’s performance more susceptible to any single economic, market, political or regulatory occurrence affecting those particular securities or issuers or that particular market, industry, group of industries, country, region, group of countries, asset class or sector than a portfolio that invests more broadly.
Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money by investing in the Portfolio.
Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Portfolio through a Contract is not a deposit or obligation of, or guaranteed by, any bank, and is not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. Government.
Risk Nondiversified Status [Member]  
Prospectus [Line Items]  
Risk [Text Block] Non-Diversification Risk.  To the extent that the Portfolio holds securities of a smaller number of issuers or invests a larger percentage of its assets in a single issuer than a diversified portfolio, the value of the Portfolio, as compared to the value of a diversified portfolio, will generally be more volatile and more sensitive to the performance of any one of those issuers and to economic, political, market or regulatory events affecting any one of those issuers.