Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	$ 731		$ 731			$ 769
Accumulated other comprehensive income, net of tax, end of period	731		731
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Other comprehensive income before reclassification, before tax	141	$ 506	(52)	$ 107
Reclassification adjustment, before tax	(9)	0	(12)	75
Effect on other comprehensive income, before tax	132	506	(64)	182
Accumulated other comprehensive income, before tax, end of period	962	772	962	772
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income before reclassification, tax	28	107	(11)	23
Reclassification adjustment, tax	(1)	0	(3)	16
Effect on other comprehensive income, tax	27	107	(14)	39
Accumulated other comprehensive income, tax, end of period	201	162	201	162
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	761	610	761	610
Other comprehensive income before reclassification, net of tax	113	399	(41)	84
Reclassification adjustment, net of tax	(8)	0	(9)	59
Effect on other comprehensive income, net of tax	105	399	(50)	143
Accumulated other comprehensive income, net of tax, end of period	761	610	761	610
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	(37)	(8)	(41)	(9)
Other comprehensive income before reclassification, before tax	0	0	2	0
Reclassification adjustment, before tax	1	1	3	2
Effect on other comprehensive income, before tax	1	1	5	2
Accumulated other comprehensive income, before tax, end of period	(36)	(7)	(36)	(7)
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	(6)	0	(7)	0
Other comprehensive income before reclassification, tax	0	0	0	0
Reclassification adjustment, tax	0	0	1	0
Effect on other comprehensive income, tax	0	0	1	0
Accumulated other comprehensive income, tax, end of period	(6)	0	(6)	0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	(30)	(7)	(30)	(7)	$ (31)	(34)	$ (8)	$ (9)
Other comprehensive income before reclassification, net of tax	0	0	2	0
Reclassification adjustment, net of tax	1	1	2	2
Effect on other comprehensive income, net of tax	1	1	4	2
Accumulated other comprehensive income, net of tax, end of period	(30)	(7)	(30)	(7)
Accumulated Net Unrealized Gain (Loss) on Deferred Costs, Reserves And Other
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	0	1	(10)	(13)
Other comprehensive income before reclassification, before tax	0	(9)	10	5
Reclassification adjustment, before tax	0	0	0	0
Effect on other comprehensive income, before tax	0	(9)	10	5
Accumulated other comprehensive income, before tax, end of period	0	(8)	0	(8)
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	0	0	(2)	(3)
Other comprehensive income before reclassification, tax	0	(2)	2	1
Reclassification adjustment, tax	0	0	0	0
Effect on other comprehensive income, tax	0	(2)	2	1
Accumulated other comprehensive income, tax, end of period	0	(2)	0	(2)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	0	(6)	0	(6)	0	(8)	1	(10)
Other comprehensive income before reclassification, net of tax	0	(7)	8	4
Reclassification adjustment, net of tax	0	0	0	0
Effect on other comprehensive income, net of tax	0	(7)	8	4
Accumulated other comprehensive income, net of tax, end of period	0	(6)	0	(6)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Change in unrealized gains, net, on investments available for sale, before tax	132	506	(64)	182
Change in pension obligations, before tax	1	1	5	2
Change in life deferred acquisition costs, life policy reserves and other, before tax	0	(9)	10	5
Effect on other comprehensive income, before tax	133	498	(49)	189
Accumulated other comprehensive income, before tax, end of period	926	757	926	757
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Change in unrealized gains, net, on investments available for sale, tax	27	107	(14)	39
Change in pension obligations, tax	0	0	1	0
Change in life deferred acquisition costs, life policy reserves and other, tax	0	(2)	2	1
Effect on other comprehensive income, tax	27	105	(11)	40
Accumulated other comprehensive income, tax, end of period	195	160	195	160
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	731	597	731	597
Change in unrealized gains, net, on investments available for sale, net of tax	105	399	(50)	143
Change in pension obligations, net of tax	1	1	4	2
Change in life deferred acquisition costs, life policy reserves and other, net of tax	0	(7)	8	4
Effect on other comprehensive income, net of tax	106	393	(38)	149
Accumulated other comprehensive income, net of tax, end of period	731	597	731	597
Previously Reported | Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	830	266	1,026	590
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	174	55	215	123
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period					656	811	211	467
Previously Reported | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	793	259	975	568
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	$ 168	$ 55	$ 206	$ 120
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period					$ 625	$ 769	$ 204	$ 448