Accumulated Other Comprehensive Income Loss - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 13,676	$ 17,805
Other comprehensive loss, net of tax	$ (654)	$ (1,128)	(337)	(4,505)
Ending balance	13,679	12,999	13,679	12,999
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,277)	(1,858)	(2,594)	1,631
OCI before reclassifications	(876)	(1,564)	(522)	(6,133)
Amounts reclassified from AOCI	26	70	74	222
OCI, before tax	(850)	(1,494)	(448)	(5,911)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	179	314	94	1,242
Other comprehensive loss, net of tax	(671)	(1,180)	(354)	(4,669)
Ending balance	(2,948)	(3,038)	(2,948)	(3,038)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(10)	(2)	(7)	(2)
OCI before reclassifications	(1)	(6)	(7)	(6)
Amounts reclassified from AOCI	2	0	4	0
OCI, before tax	1	(6)	(3)	(6)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0	1	1	1
Other comprehensive loss, net of tax	1	(5)	(2)	(5)
Ending balance	(9)	(7)	(9)	(7)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	31	30	40	6
OCI before reclassifications	(5)	51	(19)	95
Amounts reclassified from AOCI	(1)	(2)	2	(16)
OCI, before tax	(6)	49	(17)	79
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	2	(10)	4	(16)
Other comprehensive loss, net of tax	(4)	39	(13)	63
Ending balance	27	69	27	69
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	36	33	31	41
OCI before reclassifications	(1)	(24)	5	(34)
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	(1)	(24)	5	(34)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0	5	(1)	7
Other comprehensive loss, net of tax	(1)	(19)	4	(27)
Ending balance	35	14	35	14
AOCI, Liability for Future Policy Benefit, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	32	13	35	(59)
OCI before reclassifications	19	31	15	122
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	19	31	15	122
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(4)	(7)	(3)	(26)
Other comprehensive loss, net of tax	15	24	12	96
Ending balance	47	37	47	37
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,336)	(1,465)	(1,346)	(1,489)
OCI before reclassifications	1	1	0	1
Amounts reclassified from AOCI	7	15	20	46
OCI, before tax	8	16	20	47
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(2)	(3)	(4)	(10)
Other comprehensive loss, net of tax	6	13	16	37
Ending balance	(1,330)	(1,452)	(1,330)	(1,452)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,524)	(3,249)	(3,841)	128
OCI before reclassifications	(863)	(1,511)	(528)	(5,955)
Amounts reclassified from AOCI	34	83	100	252
OCI, before tax	(829)	(1,428)	(428)	(5,703)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	175	300	91	1,198
Other comprehensive loss, net of tax	(654)	(1,128)	(337)	(4,505)
Ending balance	$ (4,178)	$ (4,377)	$ (4,178)	$ (4,377)