Accumulated Other Comprehensive Income Loss - AOCI Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 17,843
Other comprehensive loss, net of tax	$ (1,152)	$ (263)	(4,586)	$ (863)
Ending balance	12,955	17,862	12,955	17,862
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,858)	2,204	1,616	2,834
OCI before reclassifications	(1,564)	(292)	(6,113)	(1,032)
Amounts reclassified from AOCI	70	(55)	222	(112)
OCI, before tax	(1,494)	(347)	(5,891)	(1,144)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	314	73	1,237	240
Other comprehensive loss, net of tax	(1,180)	(274)	(4,654)	(904)
Ending balance	(3,038)	1,930	(3,038)	1,930
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2)	(2)	(2)	(2)
OCI before reclassifications	(6)	0	(6)	0
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	(6)	0	(6)	0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	1	0	1	0
Other comprehensive loss, net of tax	(5)	0	(5)	0
Ending balance	(7)	(2)	(7)	(2)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	30	12	6	12
OCI before reclassifications	51	10	95	27
Amounts reclassified from AOCI	(2)	(9)	(16)	(26)
OCI, before tax	49	1	79	1
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(10)	0	(16)	0
Other comprehensive loss, net of tax	39	1	63	1
Ending balance	69	13	69	13
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	33	46	41	43
OCI before reclassifications	(24)	(5)	(34)	(1)
Amounts reclassified from AOCI	0	0	0	0
OCI, before tax	(24)	(5)	(34)	(1)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	5	1	7	0
Other comprehensive loss, net of tax	(19)	(4)	(27)	(1)
Ending balance	14	42	14	42
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,465)	(1,690)	(1,489)	(1,717)
OCI before reclassifications	1	1	1	(1)
Amounts reclassified from AOCI	15	17	46	53
OCI, before tax	16	18	47	52
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(3)	(4)	(10)	(11)
Other comprehensive loss, net of tax	13	14	37	41
Ending balance	(1,452)	(1,676)	(1,452)	(1,676)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,262)	570	172	1,170
OCI before reclassifications	(1,542)	(286)	(6,057)	(1,007)
Amounts reclassified from AOCI	83	(47)	252	(85)
OCI, before tax	(1,459)	(333)	(5,805)	(1,092)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	307	70	1,219	229
Other comprehensive loss, net of tax	(1,152)	(263)	(4,586)	(863)
Ending balance	$ (4,414)	$ 307	$ (4,414)	$ 307