Accumulated Other Comprehensive Income Loss - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 13,676	$ 17,805
Other comprehensive income (loss), net of tax	$ (270)	$ (1,539)	317	(3,377)
Ending balance	14,152	14,245	14,152	14,245
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,008)	(261)	(2,594)	1,631
OCI before reclassifications	(362)	(2,087)	353	(4,568)
Amounts reclassified from AOCI	21	65	48	152
OCI, before tax	(341)	(2,022)	401	(4,416)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	72	425	(84)	927
Other comprehensive income (loss), net of tax	(269)	(1,597)	317	(3,489)
Ending balance	(2,277)	(1,858)	(2,277)	(1,858)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(13)	(2)	(7)	(2)
OCI before reclassifications	2	0	(6)	0
Amounts reclassified from AOCI	2	0	2	0
OCI, before tax	4	0	(4)	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	0	1	0
Other comprehensive income (loss), net of tax	3	0	(3)	0
Ending balance	(10)	(2)	(10)	(2)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	48	5	40	6
OCI before reclassifications	(21)	38	(14)	45
Amounts reclassified from AOCI	0	(6)	3	(14)
OCI, before tax	(21)	32	(11)	31
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	4	(7)	2	(7)
Other comprehensive income (loss), net of tax	(17)	25	(9)	24
Ending balance	31	30	31	30
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	33	41	31	41
OCI before reclassifications	4	(10)	6	(10)
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	4	(10)	6	(10)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	2	(1)	2
Other comprehensive income (loss), net of tax	3	(8)	5	(8)
Ending balance	36	33	36	33
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,341)	(1,477)	(1,346)	(1,489)
OCI before reclassifications	(1)	(1)	0	(1)
Amounts reclassified from AOCI	7	16	13	31
OCI, before tax	6	15	13	30
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	(3)	(3)	(6)
Other comprehensive income (loss), net of tax	5	12	10	24
Ending balance	(1,336)	(1,465)	(1,336)	(1,465)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,254)	(1,710)	(3,841)	128
OCI before reclassifications	(372)	(2,023)	335	(4,443)
Amounts reclassified from AOCI	30	75	66	169
OCI, before tax	(342)	(1,948)	401	(4,274)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	72	409	(84)	897
Other comprehensive income (loss), net of tax	(270)	(1,539)	317	(3,377)
Ending balance	(3,524)	(3,249)	(3,524)	(3,249)
AOCI, Liability for Future Policy Benefit, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	27	(16)	35	(59)
OCI before reclassifications	6	37	(4)	91
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	6	37	(4)	91
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(1)	(8)	1	(19)
Other comprehensive income (loss), net of tax	5	29	(3)	72
Ending balance	$ 32	$ 13	$ 32	$ 13