Investment Securities - Fair Value and Gross Unrealized Losses by Aging Category (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Available-for-sale securities
Less than 12 months, Fair value	$ 13,444	$ 20,904
Less than 12 months, Gross unrealized losses	208	846
12 months or more, Fair Value	17,272	8,519
12 months or more, Gross unrealized losses	1,110	746
Total fair value	30,716	29,423
Total gross unrealized losses	1,318	1,592
Total mortgage-backed securities
Available-for-sale securities
Less than 12 months, Fair value	1,689	5,166
Less than 12 months, Gross unrealized losses	37	170
12 months or more, Fair Value	4,393	1,143
12 months or more, Gross unrealized losses	231	123
Total fair value	6,082	6,309
Total gross unrealized losses	268	293
U.S. GSEs and government agencies
Available-for-sale securities
Total fair value	7,400	9,600
Residential: U.S.
Available-for-sale securities
Less than 12 months, Fair value	474	1,187
Less than 12 months, Gross unrealized losses	16	71
12 months or more, Fair Value	1,062	260
12 months or more, Gross unrealized losses	87	40
Total fair value	1,536	1,447
Total gross unrealized losses	103	111
Residential: Non-U.S.
Available-for-sale securities
Less than 12 months, Fair value	966	2,848
Less than 12 months, Gross unrealized losses	4	25
12 months or more, Fair Value	1,653	70
12 months or more, Gross unrealized losses	7	2
Total fair value	2,619	2,918
Total gross unrealized losses	11	27
Commercial
Available-for-sale securities
Less than 12 months, Fair value	249	1,131
Less than 12 months, Gross unrealized losses	17	74
12 months or more, Fair Value	1,678	813
12 months or more, Gross unrealized losses	137	81
Total fair value	1,927	1,944
Total gross unrealized losses	154	155
Obligations of U.S. states and municipalities
Available-for-sale securities
Less than 12 months, Fair value	2,164	3,051
Less than 12 months, Gross unrealized losses	66	241
12 months or more, Fair Value	1,202	364
12 months or more, Gross unrealized losses	263	162
Total fair value	3,366	3,415
Total gross unrealized losses	329	403
Non-U.S. government debt securities
Available-for-sale securities
Less than 12 months, Fair value	7,592	6,941
Less than 12 months, Gross unrealized losses	70	321
12 months or more, Fair Value	5,475	3,848
12 months or more, Gross unrealized losses	473	357
Total fair value	13,067	10,789
Total gross unrealized losses	543	678
Corporate debt securities
Available-for-sale securities
Less than 12 months, Fair value	110	150
Less than 12 months, Gross unrealized losses	2	2
12 months or more, Fair Value	249	207
12 months or more, Gross unrealized losses	26	22
Total fair value	359	357
Total gross unrealized losses	28	24
Asset-backed securities: Collateralized loan obligations
Available-for-sale securities
Less than 12 months, Fair value	352	3,010
Less than 12 months, Gross unrealized losses	4	61
12 months or more, Fair Value	4,882	2,701
12 months or more, Gross unrealized losses	85	64
Total fair value	5,234	5,711
Total gross unrealized losses	89	125
Asset-backed securities: Other
Available-for-sale securities
Less than 12 months, Fair value	1,537	2,586
Less than 12 months, Gross unrealized losses	29	51
12 months or more, Fair Value	1,071	256
12 months or more, Gross unrealized losses	32	18
Total fair value	2,608	2,842
Total gross unrealized losses	$ 61	$ 69