v3.26.1
Investments - Fixed Maturity Securities and Short Term Investments (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]        
Percent of Total 100.00% 100.00%    
Amortized Cost $ 7,241 $ 6,572    
Allowance for Credit Losses (63) (54) $ (45) $ (60)
Gross Unrealized Gains 84 135    
Gross Unrealized Losses (387) (284)    
Fixed-maturity securities, available for sale $ 6,875 $ 6,369    
Government agency obligations as a percentage of total mortgage backed securities 70.00% 75.00%    
Obligations of state and political subdivisions        
Schedule of Investments [Line Items]        
Percent of Total 25.00% 28.00%    
Amortized Cost $ 1,800 $ 1,816    
Allowance for Credit Losses (13) (13)    
Gross Unrealized Gains 32 37    
Gross Unrealized Losses (75) (71)    
Fixed-maturity securities, available for sale $ 1,744 $ 1,769    
U.S. government and agencies        
Schedule of Investments [Line Items]        
Percent of Total 1.00% 1.00%    
Amortized Cost $ 56 $ 55    
Allowance for Credit Losses 0 0    
Gross Unrealized Gains 1 1    
Gross Unrealized Losses (5) (4)    
Fixed-maturity securities, available for sale $ 52 $ 52    
Corporate securities        
Schedule of Investments [Line Items]        
Percent of Total 48.00% 46.00%    
Amortized Cost $ 3,478 $ 2,998    
Allowance for Credit Losses (7) (6)    
Gross Unrealized Gains 38 75    
Gross Unrealized Losses (159) (115)    
Fixed-maturity securities, available for sale $ 3,350 $ 2,952    
RMBS        
Schedule of Investments [Line Items]        
Percent of Total 10.00% 10.00%    
Amortized Cost $ 694 $ 678    
Allowance for Credit Losses (27) (26)    
Gross Unrealized Gains 6 10    
Gross Unrealized Losses (49) (47)    
Fixed-maturity securities, available for sale $ 624 $ 615    
CMBS        
Schedule of Investments [Line Items]        
Percent of Total 4.00% 3.00%    
Amortized Cost $ 273 $ 197    
Allowance for Credit Losses 0 0    
Gross Unrealized Gains 2 2    
Gross Unrealized Losses (3) (1)    
Fixed-maturity securities, available for sale $ 272 $ 198    
CLOs        
Schedule of Investments [Line Items]        
Percent of Total 6.00% 7.00%    
Amortized Cost $ 469 $ 499    
Allowance for Credit Losses (16) (9)    
Gross Unrealized Gains 1 4    
Gross Unrealized Losses (80) (38)    
Fixed-maturity securities, available for sale $ 374 $ 456    
Others        
Schedule of Investments [Line Items]        
Percent of Total 3.00% 3.00%    
Amortized Cost $ 239 $ 206    
Allowance for Credit Losses 0 0    
Gross Unrealized Gains 3 3    
Gross Unrealized Losses (1) 0    
Fixed-maturity securities, available for sale 241 209    
Others | Affiliated Entity        
Schedule of Investments [Line Items]        
Amortized Cost 53 53    
Fixed-maturity securities, available for sale $ 54 $ 54    
Non-U.S. government securities        
Schedule of Investments [Line Items]        
Percent of Total 3.00% 2.00%    
Amortized Cost $ 232 $ 123    
Allowance for Credit Losses 0 0    
Gross Unrealized Gains 1 3    
Gross Unrealized Losses (15) (8)    
Fixed-maturity securities, available for sale $ 218 $ 118