Investment Securities - Fair Value and Gross Unrealized Losses by Aging Category (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Available-for-sale securities
Less than 12 months, Fair value	$ 33,159	$ 16,538
Less than 12 months, Gross unrealized losses	1,174	65
12 months or more, Fair Value	3,406	1,336
12 months or more, Gross unrealized losses	180	42
Total fair value	36,565	17,874
Total gross unrealized losses	1,354	107
Total mortgage-backed securities
Available-for-sale securities
Less than 12 months, Fair value	6,822	2,993
Less than 12 months, Gross unrealized losses	167	7
12 months or more, Fair Value	356	394
12 months or more, Gross unrealized losses	26	13
Total fair value	7,178	3,387
Total gross unrealized losses	193	20
U.S. GSEs and government agencies
Available-for-sale securities
Total fair value	9,200	2,200
Residential: U.S.
Available-for-sale securities
Less than 12 months, Fair value	1,603	303
Less than 12 months, Gross unrealized losses	54	1
12 months or more, Fair Value	30	45
12 months or more, Gross unrealized losses	1	1
Total fair value	1,633	348
Total gross unrealized losses	55	2
Residential: Non-U.S.
Available-for-sale securities
Less than 12 months, Fair value	3,392	133
Less than 12 months, Gross unrealized losses	20	1
12 months or more, Fair Value	0	0
12 months or more, Gross unrealized losses	0	0
Total fair value	3,392	133
Total gross unrealized losses	20	1
Commercial
Available-for-sale securities
Less than 12 months, Fair value	1,827	2,557
Less than 12 months, Gross unrealized losses	93	5
12 months or more, Fair Value	326	349
12 months or more, Gross unrealized losses	25	12
Total fair value	2,153	2,906
Total gross unrealized losses	118	17
Obligations of U.S. states and municipalities
Available-for-sale securities
Less than 12 months, Fair value	4,258	120
Less than 12 months, Gross unrealized losses	341	2
12 months or more, Fair Value	13	0
12 months or more, Gross unrealized losses	5	0
Total fair value	4,271	120
Total gross unrealized losses	346	2
Non-U.S. government debt securities
Available-for-sale securities
Less than 12 months, Fair value	9,832	5,060
Less than 12 months, Gross unrealized losses	374	37
12 months or more, Fair Value	1,313	510
12 months or more, Gross unrealized losses	77	9
Total fair value	11,145	5,570
Total gross unrealized losses	451	46
Corporate debt securities
Available-for-sale securities
Less than 12 months, Fair value	249	166
Less than 12 months, Gross unrealized losses	4	1
12 months or more, Fair Value	37	46
12 months or more, Gross unrealized losses	30	18
Total fair value	286	212
Total gross unrealized losses	34	19
Asset-backed securities: Collateralized loan obligations
Available-for-sale securities
Less than 12 months, Fair value	9,392	8,110
Less than 12 months, Gross unrealized losses	258	18
12 months or more, Fair Value	1,538	208
12 months or more, Gross unrealized losses	39	0
Total fair value	10,930	8,318
Total gross unrealized losses	297	18
Asset-backed securities: Other
Available-for-sale securities
Less than 12 months, Fair value	2,606	89
Less than 12 months, Gross unrealized losses	30	0
12 months or more, Fair Value	149	178
12 months or more, Gross unrealized losses	3	2
Total fair value	2,755	267
Total gross unrealized losses	$ 33	$ 2