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Brighthouse Templeton International Bond Portfolio Average Annual Total Returns
12 Months Ended 60 Months Ended 80 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Bloomberg Global Aggregate ex-U.S. (USD Hedged) Index (reflects no deduction for mutual fund fees or expenses)[Member]        
Prospectus [Line Items]        
Average Annual Return, Percent 2.80% 0.79% 1.83% 2.58%
FTSE World Government Bond Index ex-U.S. (reflects no deduction for mutual fund fees or expenses)[Member]        
Prospectus [Line Items]        
Average Annual Return, Percent 8.47% (5.21%)   (0.16%)
Class A        
Prospectus [Line Items]        
Average Annual Return, Percent 16.64% (0.44%)   (0.39%)
Class B        
Prospectus [Line Items]        
Average Annual Return, Percent 16.35% (0.69%)   (0.64%)