Securities - Fair Value of Investments with Continuous Unrealized Loss Position (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	$ 73,253	$ 47,036
Less than 12 months, Unrealized losses	3,680	636
12 months or more, Fair value	10,746	4,661
12 months or more, Unrealized losses	1,152	158
Total, Fair value	83,999	51,697
Total, Unrealized losses	4,832	794
Debt securities, available-for-sale, unrealized loss position	83,999	51,697
Debt securities, available-for-sale, unrealized loss position, accumulated loss	4,832	794
AOCI, transfers from AFS to HTM Securities, gross unrealized losses, less than 12 months	134	47
AOCI, transfers from AFS to HTM Securities, gross unrealized losses, greater than 12 months	66	28
U.S. Treasury
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	26,959	16,855
Less than 12 months, Unrealized losses	1,593	235
12 months or more, Fair value	3,198	1,944
12 months or more, Unrealized losses	414	93
Total, Fair value	30,157	18,799
Total, Unrealized losses	2,007	328
Debt securities, available-for-sale, unrealized loss position	30,157	18,799
Debt securities, available-for-sale, unrealized loss position, accumulated loss	2,007	328
Sovereign debt/sovereign guaranteed
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	8,200	6,040
Less than 12 months, Unrealized losses	221	66
12 months or more, Fair value	1,409	58
12 months or more, Unrealized losses	122	1
Total, Fair value	9,609	6,098
Total, Unrealized losses	343	67
Debt securities, available-for-sale, unrealized loss position	9,609	6,098
Debt securities, available-for-sale, unrealized loss position, accumulated loss	343	67
Agency residential mortgage-backed securities (“RMBS”)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	7,709	4,089
Less than 12 months, Unrealized losses	305	44
12 months or more, Fair value	297	457
12 months or more, Unrealized losses	23	29
Total, Fair value	8,006	4,546
Total, Unrealized losses	328	73
Debt securities, available-for-sale, unrealized loss position	8,006	4,546
Debt securities, available-for-sale, unrealized loss position, accumulated loss	328	73
Agency commercial mortgage-backed securities (“MBS”)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	6,511	2,233
Less than 12 months, Unrealized losses	353	39
12 months or more, Fair value	805	585
12 months or more, Unrealized losses	57	3
Total, Fair value	7,316	2,818
Total, Unrealized losses	410	42
Debt securities, available-for-sale, unrealized loss position	7,316	2,818
Debt securities, available-for-sale, unrealized loss position, accumulated loss	410	42
Supranational
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	4,480	3,093
Less than 12 months, Unrealized losses	179	44
12 months or more, Fair value	904	305
12 months or more, Unrealized losses	85	6
Total, Fair value	5,384	3,398
Total, Unrealized losses	264	50
Debt securities, available-for-sale, unrealized loss position	5,384	3,398
Debt securities, available-for-sale, unrealized loss position, accumulated loss	264	50
Collateralized loan obligations (“CLOs”)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	4,748	1,808
Less than 12 months, Unrealized losses	135	3
12 months or more, Fair value	313	318
12 months or more, Unrealized losses	12	2
Total, Fair value	5,061	2,126
Total, Unrealized losses	147	5
Debt securities, available-for-sale, unrealized loss position	5,061	2,126
Debt securities, available-for-sale, unrealized loss position, accumulated loss	147	5
Foreign covered bonds
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	4,307	2,694
Less than 12 months, Unrealized losses	151	23
12 months or more, Fair value	481	0
12 months or more, Unrealized losses	34	0
Total, Fair value	4,788	2,694
Total, Unrealized losses	185	23
Debt securities, available-for-sale, unrealized loss position	4,788	2,694
Debt securities, available-for-sale, unrealized loss position, accumulated loss	185	23
Non-agency commercial MBS
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	2,565	947
Less than 12 months, Unrealized losses	205	16
12 months or more, Fair value	438	222
12 months or more, Unrealized losses	62	7
Total, Fair value	3,003	1,169
Total, Unrealized losses	267	23
Debt securities, available-for-sale, unrealized loss position	3,003	1,169
Debt securities, available-for-sale, unrealized loss position, accumulated loss	267	23
Foreign government agencies
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	1,966	1,446
Less than 12 months, Unrealized losses	59	17
12 months or more, Fair value	381	15
12 months or more, Unrealized losses	25	0
Total, Fair value	2,347	1,461
Total, Unrealized losses	84	17
Debt securities, available-for-sale, unrealized loss position	2,347	1,461
Debt securities, available-for-sale, unrealized loss position, accumulated loss	84	17
Non-agency RMBS
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	1,245	1,573
Less than 12 months, Unrealized losses	73	20
12 months or more, Fair value	823	345
12 months or more, Unrealized losses	86	5
Total, Fair value	2,068	1,918
Total, Unrealized losses	159	25
Debt securities, available-for-sale, unrealized loss position	2,068	1,918
Debt securities, available-for-sale, unrealized loss position, accumulated loss	159	25
State and political subdivisions
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	1,306	1,848
Less than 12 months, Unrealized losses	173	40
12 months or more, Fair value	461	13
12 months or more, Unrealized losses	68	0
Total, Fair value	1,767	1,861
Total, Unrealized losses	241	40
Debt securities, available-for-sale, unrealized loss position	1,767	1,861
Debt securities, available-for-sale, unrealized loss position, accumulated loss	241	40
U.S. government agencies
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	1,517	1,780
Less than 12 months, Unrealized losses	113	27
12 months or more, Fair value	182	0
12 months or more, Unrealized losses	23	0
Total, Fair value	1,699	1,780
Total, Unrealized losses	136	27
Debt securities, available-for-sale, unrealized loss position	1,699	1,780
Debt securities, available-for-sale, unrealized loss position, accumulated loss	136	27
Other asset-backed securities (“ABS”)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	1,087	1,383
Less than 12 months, Unrealized losses	71	20
12 months or more, Fair value	495	201
12 months or more, Unrealized losses	32	2
Total, Fair value	1,582	1,584
Total, Unrealized losses	103	22
Debt securities, available-for-sale, unrealized loss position	1,582	1,584
Debt securities, available-for-sale, unrealized loss position, accumulated loss	103	22
Corporate bonds
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, Fair value	653	1,247
Less than 12 months, Unrealized losses	49	42
12 months or more, Fair value	559	198
12 months or more, Unrealized losses	109	10
Total, Fair value	1,212	1,445
Total, Unrealized losses	158	52
Debt securities, available-for-sale, unrealized loss position	1,212	1,445
Debt securities, available-for-sale, unrealized loss position, accumulated loss	$ 158	$ 52