Investment Securities - Schedule of Contractual Maturities of Debt Securities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	$ 9,673
Available for sale, under 1 year, fair value	9,663
Available for sale, 1 to 5 years, amortized cost	38,325
Available for sale, 1 to 5 years, fair value	37,108
Available for sale, 6 to 10 years, amortized cost	15,147
Available for sale, 6 to 10 years, fair value	15,059
Available for sale, over 10 years, amortized cost	12,972
Available for sale, over 10 years, fair value	12,518
Available for sale, amortized cost	76,117	$ 73,440
Available for sale, fair value	74,348	73,399
Held to maturity, amortized cost	45,203	42,430
Held to maturity, fair value	42,834	42,271
US Treasury and federal agencies, direct obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	2,427
Available for sale, under 1 year, fair value	2,417
Available for sale, 1 to 5 years, amortized cost	18,654
Available for sale, 1 to 5 years, fair value	17,907
Available for sale, 6 to 10 years, amortized cost	606
Available for sale, 6 to 10 years, fair value	619
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	21,687	18,111
Available for sale, fair value	20,943	17,939
Held to maturity, under 1 year, amortized cost	701
Held to maturity, under 1 year, fair value	702
Held to maturity, 1 to 5 years, amortized cost	2
Held to maturity, 1 to 5 years, fair value	2
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	16
Held to maturity, over 10 years, fair value	17
Held to maturity, amortized cost	720	2,170
Held to maturity, fair value	722	2,180
US Treasury and federal agencies, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	63
Available for sale, under 1 year, fair value	63
Available for sale, 1 to 5 years, amortized cost	760
Available for sale, 1 to 5 years, fair value	761
Available for sale, 6 to 10 years, amortized cost	8,443
Available for sale, 6 to 10 years, fair value	8,409
Available for sale, over 10 years, amortized cost	9,938
Available for sale, over 10 years, fair value	9,508
Available for sale, amortized cost	19,204	18,154
Available for sale, fair value	18,741	18,208
Held to maturity, under 1 year, amortized cost	133
Held to maturity, under 1 year, fair value	130
Held to maturity, 1 to 5 years, amortized cost	428
Held to maturity, 1 to 5 years, fair value	418
Held to maturity, 6 to 10 years, amortized cost	4,619
Held to maturity, 6 to 10 years, fair value	4,245
Held to maturity, over 10 years, amortized cost	30,604
Held to maturity, over 10 years, fair value	28,700
Held to maturity, amortized cost	35,784	33,481
Held to maturity, fair value	33,493	33,265
Total U.S. Treasury and federal agencies
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	2,490
Available for sale, under 1 year, fair value	2,480
Available for sale, 1 to 5 years, amortized cost	19,414
Available for sale, 1 to 5 years, fair value	18,668
Available for sale, 6 to 10 years, amortized cost	9,049
Available for sale, 6 to 10 years, fair value	9,028
Available for sale, over 10 years, amortized cost	9,938
Available for sale, over 10 years, fair value	9,508
Available for sale, amortized cost	40,891	36,265
Available for sale, fair value	39,684	36,147
Held to maturity, under 1 year, amortized cost	834
Held to maturity, under 1 year, fair value	832
Held to maturity, 1 to 5 years, amortized cost	430
Held to maturity, 1 to 5 years, fair value	420
Held to maturity, 6 to 10 years, amortized cost	4,620
Held to maturity, 6 to 10 years, fair value	4,246
Held to maturity, over 10 years, amortized cost	30,620
Held to maturity, over 10 years, fair value	28,717
Held to maturity, amortized cost	36,504	35,651
Held to maturity, fair value	34,215	35,445
Non-U.S. debt securities, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	141
Available for sale, under 1 year, fair value	140
Available for sale, 1 to 5 years, amortized cost	501
Available for sale, 1 to 5 years, fair value	501
Available for sale, 6 to 10 years, amortized cost	31
Available for sale, 6 to 10 years, fair value	31
Available for sale, over 10 years, amortized cost	1,599
Available for sale, over 10 years, fair value	1,596
Available for sale, amortized cost	2,272	1,986
Available for sale, fair value	2,268	1,995
Non-U.S. debt securities, asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	283
Available for sale, under 1 year, fair value	281
Available for sale, 1 to 5 years, amortized cost	963
Available for sale, 1 to 5 years, fair value	961
Available for sale, 6 to 10 years, amortized cost	433
Available for sale, 6 to 10 years, fair value	432
Available for sale, over 10 years, amortized cost	394
Available for sale, over 10 years, fair value	392
Available for sale, amortized cost	2,073	2,087
Available for sale, fair value	2,066	2,087
Non-U.S. sovereign, supranational and non-U.S. agency
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	4,660
Available for sale, under 1 year, fair value	4,661
Available for sale, 1 to 5 years, amortized cost	12,768
Available for sale, 1 to 5 years, fair value	12,434
Available for sale, 6 to 10 years, amortized cost	3,679
Available for sale, 6 to 10 years, fair value	3,620
Available for sale, over 10 years, amortized cost	16
Available for sale, over 10 years, fair value	14
Available for sale, amortized cost	21,123	23,533
Available for sale, fair value	20,729	23,547
Held to maturity, under 1 year, amortized cost	233
Held to maturity, under 1 year, fair value	233
Held to maturity, 1 to 5 years, amortized cost	3,529
Held to maturity, 1 to 5 years, fair value	3,459
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	0
Held to maturity, over 10 years, fair value	0
Held to maturity, amortized cost	3,763	1,564
Held to maturity, fair value	3,693	1,555
Non-U.S. debt securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	1,008
Available for sale, under 1 year, fair value	1,009
Available for sale, 1 to 5 years, amortized cost	2,321
Available for sale, 1 to 5 years, fair value	2,232
Available for sale, 6 to 10 years, amortized cost	110
Available for sale, 6 to 10 years, fair value	101
Available for sale, over 10 years, amortized cost	55
Available for sale, over 10 years, fair value	47
Available for sale, amortized cost	3,494	3,113
Available for sale, fair value	3,389	3,098
Total non-U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	6,092
Available for sale, under 1 year, fair value	6,091
Available for sale, 1 to 5 years, amortized cost	16,553
Available for sale, 1 to 5 years, fair value	16,128
Available for sale, 6 to 10 years, amortized cost	4,253
Available for sale, 6 to 10 years, fair value	4,184
Available for sale, over 10 years, amortized cost	2,064
Available for sale, over 10 years, fair value	2,049
Available for sale, amortized cost	28,962	30,719
Available for sale, fair value	28,452	30,727
Held to maturity, under 1 year, amortized cost	233
Held to maturity, under 1 year, fair value	233
Held to maturity, 1 to 5 years, amortized cost	3,529
Held to maturity, 1 to 5 years, fair value	3,459
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	0
Held to maturity, over 10 years, fair value	0
Held to maturity, amortized cost	3,763	1,564
Held to maturity, fair value	3,693	1,555
Asset-backed securities, student loans
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	95
Available for sale, under 1 year, fair value	97
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	0
Available for sale, 6 to 10 years, fair value	0
Available for sale, over 10 years, amortized cost	91
Available for sale, over 10 years, fair value	90
Available for sale, amortized cost	186	209
Available for sale, fair value	187	211
Held to maturity, under 1 year, amortized cost	338
Held to maturity, under 1 year, fair value	330
Held to maturity, 1 to 5 years, amortized cost	29
Held to maturity, 1 to 5 years, fair value	28
Held to maturity, 6 to 10 years, amortized cost	988
Held to maturity, 6 to 10 years, fair value	990
Held to maturity, over 10 years, amortized cost	3,296
Held to maturity, over 10 years, fair value	3,272
Held to maturity, amortized cost	4,651	4,908
Held to maturity, fair value	4,620	4,942
Asset-backed securities, collateralized loan obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	110
Available for sale, under 1 year, fair value	110
Available for sale, 1 to 5 years, amortized cost	412
Available for sale, 1 to 5 years, fair value	410
Available for sale, 6 to 10 years, amortized cost	1,246
Available for sale, 6 to 10 years, fair value	1,241
Available for sale, over 10 years, amortized cost	652
Available for sale, over 10 years, fair value	650
Available for sale, amortized cost	2,420	2,155
Available for sale, fair value	2,411	2,155
Non-agency CMBS and RMBS
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	0
Available for sale, under 1 year, fair value	0
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	0
Available for sale, 6 to 10 years, fair value	0
Available for sale, over 10 years, amortized cost	170
Available for sale, over 10 years, fair value	168
Available for sale, amortized cost	170	52
Available for sale, fair value	168	52
Held to maturity, under 1 year, amortized cost	86
Held to maturity, under 1 year, fair value	93
Held to maturity, 1 to 5 years, amortized cost	124
Held to maturity, 1 to 5 years, fair value	125
Held to maturity, 6 to 10 years, amortized cost	0
Held to maturity, 6 to 10 years, fair value	0
Held to maturity, over 10 years, amortized cost	75
Held to maturity, over 10 years, fair value	88
Held to maturity, amortized cost	285	307
Held to maturity, fair value	306	329
Asset-backed securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	0
Available for sale, under 1 year, fair value	0
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	90
Available for sale, 6 to 10 years, fair value	90
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	90	90
Available for sale, fair value	90	91
Total asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	205
Available for sale, under 1 year, fair value	207
Available for sale, 1 to 5 years, amortized cost	412
Available for sale, 1 to 5 years, fair value	410
Available for sale, 6 to 10 years, amortized cost	1,336
Available for sale, 6 to 10 years, fair value	1,331
Available for sale, over 10 years, amortized cost	913
Available for sale, over 10 years, fair value	908
Available for sale, amortized cost	2,866	2,506
Available for sale, fair value	2,856	2,509
Held to maturity, under 1 year, amortized cost	424
Held to maturity, under 1 year, fair value	423
Held to maturity, 1 to 5 years, amortized cost	153
Held to maturity, 1 to 5 years, fair value	153
Held to maturity, 6 to 10 years, amortized cost	988
Held to maturity, 6 to 10 years, fair value	990
Held to maturity, over 10 years, amortized cost	3,371
Held to maturity, over 10 years, fair value	3,360
Held to maturity, amortized cost	4,936	5,215
Held to maturity, fair value	4,926	5,271
State and political subdivisions
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	178
Available for sale, under 1 year, fair value	178
Available for sale, 1 to 5 years, amortized cost	494
Available for sale, 1 to 5 years, fair value	496
Available for sale, 6 to 10 years, amortized cost	468
Available for sale, 6 to 10 years, fair value	475
Available for sale, over 10 years, amortized cost	57
Available for sale, over 10 years, fair value	53
Available for sale, amortized cost	1,197	1,216
Available for sale, fair value	1,202	1,272
Other U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	708
Available for sale, under 1 year, fair value	707
Available for sale, 1 to 5 years, amortized cost	1,452
Available for sale, 1 to 5 years, fair value	1,406
Available for sale, 6 to 10 years, amortized cost	41
Available for sale, 6 to 10 years, fair value	41
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	2,201	2,734
Available for sale, fair value	2,154	$ 2,744
Total
Contractual Maturities Of Debt Investment Securities [Line Items]
Held to maturity, under 1 year, amortized cost	1,491
Held to maturity, under 1 year, fair value	1,488
Held to maturity, 1 to 5 years, amortized cost	4,112
Held to maturity, 1 to 5 years, fair value	4,032
Held to maturity, 6 to 10 years, amortized cost	5,609
Held to maturity, 6 to 10 years, fair value	5,237
Held to maturity, over 10 years, amortized cost	33,991
Held to maturity, over 10 years, fair value	32,077
Held to maturity, amortized cost	45,203
Held to maturity, fair value	$ 42,834