Accumulated Other Comprehensive Income (AOCI) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (435)
AOCI, net of tax, end of period	(442)
AOCI on Net Unrecognized Investment Gain (Loss)
AOCI, Before Tax
AOCI, before tax, beginning of period	(570)	$ (847)
Other comprehensive income before reclassification, before tax	(65)	163
Reclassification adjustment, before tax	10	0
Effect on other comprehensive income, before tax	(55)	163
AOCI, before tax, end of period	(625)	(684)
AOCI, Tax
AOCI, tax, beginning of period	(123)	(182)
Other comprehensive income before reclassification, tax	(13)	35
Reclassification adjustment, tax	2	0
Effect on other comprehensive income, tax	(11)	35
AOCI, tax, end of period	(134)	(147)
AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax	(447)	(665)
Other comprehensive income before reclassification, net of tax	(52)	128
Reclassification adjustment, net of tax	8	0
Effect on other comprehensive income, net of tax	(44)	128
AOCI, net of tax, end of period	(491)	(537)
AOCI on Pension Obligations
AOCI, Before Tax
AOCI, before tax, beginning of period	30	36
Other comprehensive income before reclassification, before tax	0	(5)
Reclassification adjustment, before tax	0	(1)
Effect on other comprehensive income, before tax	0	(6)
AOCI, before tax, end of period	30	30
AOCI, Tax
AOCI, tax, beginning of period	8	9
Other comprehensive income before reclassification, tax	0	(1)
Reclassification adjustment, tax	0	0
Effect on other comprehensive income, tax	0	(1)
AOCI, tax, end of period	8	8
AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax	22	27
Other comprehensive income before reclassification, net of tax	0	(4)
Reclassification adjustment, net of tax	0	(1)
Effect on other comprehensive income, net of tax	0	(5)
AOCI, net of tax, end of period	22	22
AOCI on Life Policy Reserves, Reinsurance Recoverable And Other
AOCI, Before Tax
AOCI, before tax, beginning of period	(13)	29
Other comprehensive income before reclassification, before tax	47	(45)
Reclassification adjustment, before tax	0	0
Effect on other comprehensive income, before tax	47	(45)
AOCI, before tax, end of period	34	(16)
AOCI, Tax
AOCI, tax, beginning of period	(3)	5
Other comprehensive income before reclassification, tax	10	(9)
Reclassification adjustment, tax	0	0
Effect on other comprehensive income, tax	10	(9)
AOCI, tax, end of period	7	(4)
AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax	(10)	24
Other comprehensive income before reclassification, net of tax	37	(36)
Reclassification adjustment, net of tax	0	0
Effect on other comprehensive income, net of tax	37	(36)
AOCI, net of tax, end of period	27	(12)
Summary of AOCI
AOCI, Before Tax
AOCI, before tax, beginning of period	(553)	(782)
Change in unrealized gains, net, on investments available for sale, before tax	(55)	163
Change in pension obligations, before tax	0	(6)
Change in life policy reserves, reinsurance recoverable and other, before tax	47	(45)
Effect on other comprehensive income, before tax	(8)	112
AOCI, before tax, end of period	(561)	(670)
AOCI, Tax
AOCI, tax, beginning of period	(118)	(168)
Change in unrealized gains, net, on investments available for sale, tax	(11)	35
Change in pension obligations, tax	0	(1)
Change in Life Policy Reserves, Reinsurance Recoverable and Other, Tax	10	(9)
Effect on other comprehensive income, tax	(1)	25
AOCI, tax, end of period	(119)	(143)
AOCI, Net of Tax
Accumulated Other Comprehensive Income (Loss), Net of Tax	(435)	(614)
Change in unrealized gains, net, on investments available for sale, net of tax	(44)	128
Change in pension obligations, net of tax	0	(5)
Change in Life Policy Reserves, Reinsurance Recoverable and Other, Net of Tax	37	(36)
Effect on other comprehensive income, net of tax	(7)	87
AOCI, net of tax, end of period	$ (442)	$ (527)