Investments - Fixed Maturities and Equity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Available-for-sale Securities Including Securities Pledged [Line Items]
Securities pledged, Amortized Cost	$ 725	$ 169
U.S. Treasuries
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	554	535
Gross Unrealized Capital Gains	137	186
Gross Unrealized Capital Losses	0	0
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	691	721
OTTI	0	0
U.S. Government agencies and authorities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	20	18
Gross Unrealized Capital Gains	0	1
Gross Unrealized Capital Losses	0	0
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	20	19
OTTI	0	0
State, municipalities and political subdivisions
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	716	698
Gross Unrealized Capital Gains	88	116
Gross Unrealized Capital Losses	1	0
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	803	814
OTTI	0	0
U.S. corporate public securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	7,314	7,632
Gross Unrealized Capital Gains	994	1,531
Gross Unrealized Capital Losses	39	7
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	8,269	9,156
OTTI	0	0
U.S. corporate private securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	3,620	3,870
Gross Unrealized Capital Gains	334	536
Gross Unrealized Capital Losses	15	27
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	3,939	4,379
OTTI	0	0
Foreign corporate public securities and foreign governments
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	2,352	2,539
Gross Unrealized Capital Gains	253	413
Gross Unrealized Capital Losses	14	1
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	2,591	2,951
OTTI	0	0
Foreign corporate private securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	2,563	2,991
Gross Unrealized Capital Gains	188	348
Gross Unrealized Capital Losses	1	25
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	2,703	3,303
OTTI	47	11
Residential mortgage-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	3,081	4,071
Gross Unrealized Capital Gains	97	171
Gross Unrealized Capital Losses	20	15
Embedded Derivatives	7	11
Fixed maturities including securities pledged, Fair Value	3,164	4,237
OTTI	1	1
Commercial mortgage-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	2,766	2,712
Gross Unrealized Capital Gains	130	207
Gross Unrealized Capital Losses	15	26
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	2,881	2,893
OTTI	0	0
Other asset-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	1,341	1,500
Gross Unrealized Capital Gains	16	28
Gross Unrealized Capital Losses	6	6
Embedded Derivatives	0	0
Fixed maturities including securities pledged, Fair Value	1,351	1,520
OTTI	0	2
Fixed maturities
Available-for-sale Securities Including Securities Pledged [Line Items]
Amortized Cost	24,327	26,566
Total fixed maturities, less securities pledged, Amortized Cost	23,602	26,397
Gross Unrealized Capital Gains	2,237	3,537
Total fixed maturities, less securities pledged, Gross Unrealized Capital Gains	2,163	3,485
Gross Unrealized Capital Losses	111	107
Total fixed maturities, less securities pledged, Gross Unrealized Capital Losses	111	106
Embedded Derivatives	7	11
Fixed maturities including securities pledged, Fair Value	26,412	29,993
Total fixed maturities, less securities pledged, Fair Value	25,613	29,773
OTTI	48	14
Collateral Pledged
Available-for-sale Securities Including Securities Pledged [Line Items]
Securities pledged, Gross Unrealized Capital Losses	799	220
Collateral Pledged | Fixed maturities
Available-for-sale Securities Including Securities Pledged [Line Items]
Securities pledged, Amortized Cost	725	169
Securities pledged, Gross Unrealized Capital Gains	74	52
Securities pledged, Gross Unrealized Capital Losses	0	1
Embedded Derivatives	0	0
Securities pledged, Gross Unrealized Capital Losses	799	220
OTTI	$ 0	$ 0