v3.26.3
Reinsurance - Summary of the Composition of Pool of Assets (Details) - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Effects of Reinsurance [Line Items]    
Fixed maturity securities - available for sale $ 71,642 $ 71,032
Fixed maturity securities - fair value option 649 741
Short-term investments 10,183 11,141
Other 4,717 4,773
Total assets 161,861 161,254
Carrying Value    
Effects of Reinsurance [Line Items]    
Other 7 16
Commercial mortgage and other loans    
Effects of Reinsurance [Line Items]    
Loans, carrying value 2,096 2,495
Fortitude Holdings    
Effects of Reinsurance [Line Items]    
Change in net unrealized gains (losses), gross (73) 85
Change in net unrealized gains (losses), net of tax (58) 67
Derivative asset, fair value of collateral 2 1
Derivative liability, fair value of collateral 29 31
Fortitude Holdings | Carrying Value    
Effects of Reinsurance [Line Items]    
Fixed maturity securities - available for sale 1,559 1,780
Fixed maturity securities - fair value option 639 734
Short-term investments 299 43
Funds withheld investment assets 2,722 2,916
Derivative assets, net 0 0
Other 25 137
Total assets 2,747 3,053
Fortitude Holdings | Estimated Fair Value    
Effects of Reinsurance [Line Items]    
Fixed maturity securities - available for sale 1,559 1,780
Fixed maturity securities - fair value option 639 734
Short-term investments 299 43
Funds withheld investment assets 2,714 2,901
Derivative assets, net 0 0
Other, fair value 25 137
Total 2,739 3,038
Fortitude Holdings | Commercial mortgage and other loans | Carrying Value    
Effects of Reinsurance [Line Items]    
Loans, carrying value 225 359
Fortitude Holdings | Commercial mortgage and other loans | Estimated Fair Value    
Effects of Reinsurance [Line Items]    
Loans, fair value $ 217 $ 344