v3.25.1
Investments - Asset Types - Fixed Maturity Investments (Details) - USD ($)
$ in Millions
Mar. 31, 2025
Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value $ 5,324 $ 4,906
Short-term and fixed maturity investments 6,503 6,170
U.S. government and agency    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 567 407
Short-term and fixed maturity investments 579 420
U.K. government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 39 29
Short-term and fixed maturity investments 53 44
Other government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 273 268
Short-term and fixed maturity investments 364 359
Corporate    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 2,569 2,343
Short-term and fixed maturity investments 3,427 3,261
Municipal    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 76 79
Short-term and fixed maturity investments 105 109
Residential mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 409 373
Short-term and fixed maturity investments 444 421
Residential Mortgage-backed Securities, Issued by US Government Agencies    
Debt and Equity Securities, FV-NI [Line Items]    
Short-term and fixed maturity investments 228 234
Commercial mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 643 682
Short-term and fixed maturity investments 742 784
Commercial Mortgage-Backed Securities, Issued by US Government Agencies    
Debt and Equity Securities, FV-NI [Line Items]    
Short-term and fixed maturity investments 49 57
Asset-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, available-for-sale, at fair value 748 725
Short-term and fixed maturity investments 789 772
Fixed maturity investments    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value [1] 1,179 1,263
Investments, available-for-sale, at fair value [1] 4,924 4,691
Fixed maturity investments | U.S. government and agency    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 12 13
Investments, available-for-sale, at fair value 241 213
Fixed maturity investments | U.K. government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 14 15
Investments, available-for-sale, at fair value 39 29
Fixed maturity investments | Other government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 91 91
Investments, available-for-sale, at fair value 270 266
Fixed maturity investments | Corporate    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 858 917
Investments, available-for-sale, at fair value 2,498 2,324
Fixed maturity investments | Municipal    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 29 30
Investments, available-for-sale, at fair value 76 79
Fixed maturity investments | Residential mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 35 48
Investments, available-for-sale, at fair value 409 373
Fixed maturity investments | Commercial mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 99 102
Investments, available-for-sale, at fair value 643 682
Fixed maturity investments | Asset-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 41 47
Investments, available-for-sale, at fair value 748 725
Short-term investments    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value 0 1
Investments, available-for-sale, at fair value 400 215
Short-term investments | U.S. government and agency    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 326 194
Short-term investments | U.K. government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 0 0
Short-term investments | Other government    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 3 2
Short-term investments | Corporate    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   1
Investments, available-for-sale, at fair value 71 19
Short-term investments | Municipal    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 0 0
Short-term investments | Residential mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 0 0
Short-term investments | Commercial mortgage-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value 0 0
Short-term investments | Asset-backed    
Debt and Equity Securities, FV-NI [Line Items]    
Investments, trading, at fair value   0
Investments, available-for-sale, at fair value $ 0 $ 0
[1] See Note 17 for additional information regarding related party transactions.