v3.24.1.u1
Investments - Value of other securities measured at fair value based on election of the fair value option (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2024
Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities [1] $ 4,646 $ 4,578
Equity securities [1] 76 63
Total    
Debt and Equity Securities, FV-NI [Line Items]    
Total $ 4,722 $ 4,641
Total | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 100.00% 100.00%
Fixed maturity securities    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 4,646 $ 4,578
Fixed maturity securities | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 98.00% 99.00%
Fixed maturity securities | Obligations of states, municipalities and political subdivisions    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 39 $ 40
Fixed maturity securities | Obligations of states, municipalities and political subdivisions | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 1.00% 1.00%
Fixed maturity securities | Non-U.S. governments    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 13 $ 13
Fixed maturity securities | Non-U.S. governments | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 0.00% 0.00%
Fixed maturity securities | Corporate debt    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 2,704 $ 2,653
Fixed maturity securities | Corporate debt | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 57.00% 57.00%
Fixed maturity securities | Mortgage-backed, asset-backed and collateralized    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 1,890 $ 1,872
Fixed maturity securities | Mortgage-backed, asset-backed and collateralized | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 40.00% 41.00%
Fixed maturity securities | RMBS    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 169 $ 170
Fixed maturity securities | RMBS | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 4.00% 4.00%
Fixed maturity securities | CMBS    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 240 $ 228
Fixed maturity securities | CMBS | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 5.00% 5.00%
Fixed maturity securities | CLO    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 446 $ 423
Fixed maturity securities | CLO | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 9.00% 9.00%
Fixed maturity securities | ABS    
Debt and Equity Securities, FV-NI [Line Items]    
Total fixed maturity securities $ 1,035 $ 1,051
Fixed maturity securities | ABS | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 22.00% 23.00%
Equity securities    
Debt and Equity Securities, FV-NI [Line Items]    
Equity securities $ 76 $ 63
Equity securities | Investment Concentration Risk | Investments    
Debt and Equity Securities, FV-NI [Line Items]    
Concentration risk (as a percent) 2.00% 1.00%
[1] See Note 9 for details of balances associated with variable interest entities