v3.26.1
INVESTMENTS - Held-to-Maturity Debt Securities (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost $ 15,509   $ 16,125      
Allowance for Credit Losses 4 $ 4 5 $ 5 $ 5 $ 5
Total fixed maturity securities, held-to-maturity, amortized cost 15,505 [1]   16,120      
Gross Unrealized Gains 8   87      
Gross Unrealized Losses 1,257   731      
Fair Value 14,256   15,476      
Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 15,509   16,125      
Allowance for Credit Losses 4   5      
Total fixed maturity securities, held-to-maturity, amortized cost 15,505   16,120      
Gross Unrealized Gains 8   87      
Gross Unrealized Losses 1,257   731      
Fair Value 14,256   15,476      
Japan government and agencies | Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 14,901   15,461      
Allowance for Credit Losses 1   2      
Total fixed maturity securities, held-to-maturity, amortized cost 14,900   15,459      
Gross Unrealized Gains 5   81      
Gross Unrealized Losses 1,209   713      
Fair Value 13,696   14,827      
Municipalities            
Schedule of Held-to-maturity Securities [Line Items]            
Fair Value 205   229      
Municipalities | Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 225   235      
Allowance for Credit Losses 0   0      
Total fixed maturity securities, held-to-maturity, amortized cost 225   235      
Gross Unrealized Gains 0   0      
Gross Unrealized Losses 20   6      
Fair Value 205   229      
Public utilities            
Schedule of Held-to-maturity Securities [Line Items]            
Fair Value 26   29      
Public utilities | Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 31   32      
Allowance for Credit Losses 0   0      
Total fixed maturity securities, held-to-maturity, amortized cost 31   32      
Gross Unrealized Gains 0   0      
Gross Unrealized Losses 5   3      
Fair Value 26   29      
Sovereign and supranational            
Schedule of Held-to-maturity Securities [Line Items]            
Fair Value 315   375      
Sovereign and supranational | Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 337   381      
Allowance for Credit Losses 3   3      
Total fixed maturity securities, held-to-maturity, amortized cost 334   378      
Gross Unrealized Gains 3   6      
Gross Unrealized Losses 22   9      
Fair Value 315   375      
Other corporate            
Schedule of Held-to-maturity Securities [Line Items]            
Fair Value 14   16      
Other corporate | Yen-denominated            
Schedule of Held-to-maturity Securities [Line Items]            
Amortized Cost 15   16      
Allowance for Credit Losses 0   0      
Total fixed maturity securities, held-to-maturity, amortized cost 15   16      
Gross Unrealized Gains 0   0      
Gross Unrealized Losses 1   0      
Fair Value $ 14   $ 16      
[1] Net of allowance for credit losses