SCHEDULE I - SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Millions	Dec. 31, 2023 USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	$ 24,111
Market Value	23,437
Amount Shown in Balance Sheet	23,439
Fixed maturities | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	16,305
Market Value	15,932
Amount Shown in Balance Sheet	15,932
Fixed maturities | Fixed maturities - held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	859
Market Value	850
Amount Shown in Balance Sheet	851
U.S. government and government agencies | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	265
Market Value	247
Amount Shown in Balance Sheet	247
State, municipalities and political subdivisions | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	138
Market Value	128
Amount Shown in Balance Sheet	128
Foreign government securities | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	859
Market Value	835
Amount Shown in Balance Sheet	835
Foreign corporate securities | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	1,807
Market Value	1,759
Amount Shown in Balance Sheet	1,759
Foreign corporate securities | Fixed maturities - held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	84
Market Value	90
Amount Shown in Balance Sheet	83
Public utilities | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	238
Market Value	231
Amount Shown in Balance Sheet	231
Public utilities | Fixed maturities - held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	4
Market Value	5
Amount Shown in Balance Sheet	4
All other corporate bonds | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	8,990
Market Value	8,907
Amount Shown in Balance Sheet	8,907
All other corporate bonds | Fixed maturities - held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	750
Market Value	733
Amount Shown in Balance Sheet	743
Commercial | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	575
Market Value	522
Amount Shown in Balance Sheet	522
Commercial | Fixed maturities - held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	21
Market Value	21
Amount Shown in Balance Sheet	21
Agency residential | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	2,531
Market Value	2,435
Amount Shown in Balance Sheet	2,435
Non-agency residential | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	429
Market Value	441
Amount Shown in Balance Sheet	441
Redeemable preferred stock | Fixed maturities - available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	474
Market Value	427
Amount Shown in Balance Sheet	427
Equity securities at fair value
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	91
Market Value	91
Amount Shown in Balance Sheet	91
Short-term investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	1,298
Market Value	1,298
Amount Shown in Balance Sheet	1,298
Other invested assets
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	3,259
Market Value	3,259
Amount Shown in Balance Sheet	3,259
Other Invested Assets, at Fair Value
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	1,773
Market Value	1,481
Amount Shown in Balance Sheet	1,481
Cash
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	527
Market Value	527
Amount Shown in Balance Sheet	$ 527