Investment Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 73,440	$ 57,987
Available for sale, gross unrealized gains	404	1,087
Available for sale, gross unrealized losses	445	26
Available-for-sale, fair value	73,399	59,048
Held to maturity, amortized cost	42,430	48,929
Investment securities held-to-maturity	42,271	50,003
Debt securities, held-to-maturity, allowance for credit loss	0	3
US Treasury and federal agencies, direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	18,111	6,453
Available for sale, gross unrealized gains	24	123
Available for sale, gross unrealized losses	196	1
Available-for-sale, fair value	17,939	6,575
Held to maturity, amortized cost	2,170	6,057
Held to maturity, gross unrealized gains	10	83
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	2,180	6,140
US Treasury and federal agencies, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	18,154	13,891
Available for sale, gross unrealized gains	148	421
Available for sale, gross unrealized losses	94	7
Available-for-sale, fair value	18,208	14,305
Held to maturity, amortized cost	33,481	36,901
Held to maturity, gross unrealized gains	362	955
Held to maturity, gross unrealized losses	578	67
Investment securities held-to-maturity	33,265	37,789
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	36,265	20,344
Available for sale, gross unrealized gains	172	544
Available for sale, gross unrealized losses	290	8
Available-for-sale, fair value	36,147	20,880
Held to maturity, amortized cost	35,651	42,958
Held to maturity, gross unrealized gains	372	1,038
Held to maturity, gross unrealized losses	578	67
Investment securities held-to-maturity	35,445	43,929
Non-U.S. debt securities, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,986	1,994
Available for sale, gross unrealized gains	12	4
Available for sale, gross unrealized losses	3	2
Available-for-sale, fair value	1,995	1,996
Held to maturity, amortized cost	0	303
Held to maturity, gross unrealized gains	0	68
Held to maturity, gross unrealized losses	0	4
Investment securities held-to-maturity	0	367
Non-U.S. debt securities, asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,087	2,294
Available for sale, gross unrealized gains	2	1
Available for sale, gross unrealized losses	2	4
Available-for-sale, fair value	2,087	2,291
Non-U.S. sovereign, supranational and non-U.S. agency
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	23,533	21,769
Available for sale, gross unrealized gains	114	321
Available for sale, gross unrealized losses	100	3
Available-for-sale, fair value	23,547	22,087
Held to maturity, amortized cost	1,564	342
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	9	0
Investment securities held-to-maturity	1,555	342
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,113	3,297
Available for sale, gross unrealized gains	17	58
Available for sale, gross unrealized losses	32	0
Available-for-sale, fair value	3,098	3,355
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	30,719	29,354
Available for sale, gross unrealized gains	145	384
Available for sale, gross unrealized losses	137	9
Available-for-sale, fair value	30,727	29,729
Held to maturity, amortized cost	1,564	645
Held to maturity, gross unrealized gains	0	68
Held to maturity, gross unrealized losses	9	4
Investment securities held-to-maturity	1,555	709
Asset-backed securities, student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	209	313
Available for sale, gross unrealized gains	2	2
Available for sale, gross unrealized losses	0	1
Available-for-sale, fair value	211	314
Held to maturity, amortized cost	4,908	4,774
Held to maturity, gross unrealized gains	48	33
Held to maturity, gross unrealized losses	14	25
Investment securities held-to-maturity	4,942	4,782
Asset-backed securities, collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,155	2,969
Available for sale, gross unrealized gains	2	3
Available for sale, gross unrealized losses	2	6
Available-for-sale, fair value	2,155	2,966
Asset-backed securities, non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	52	76
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	0	0
Available-for-sale, fair value	52	78
Held to maturity, amortized cost	307	554
Held to maturity, gross unrealized gains	22	30
Held to maturity, gross unrealized losses	0	1
Investment securities held-to-maturity	329	583
Asset-backed securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	90	90
Available for sale, gross unrealized gains	1	0
Available for sale, gross unrealized losses	0	0
Available-for-sale, fair value	91	90
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,506	3,448
Available for sale, gross unrealized gains	5	7
Available for sale, gross unrealized losses	2	7
Available-for-sale, fair value	2,509	3,448
Held to maturity, amortized cost	5,215	5,328
Held to maturity, gross unrealized gains	70	63
Held to maturity, gross unrealized losses	14	26
Investment securities held-to-maturity	5,271	5,365
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,216	1,470
Available for sale, gross unrealized gains	59	80
Available for sale, gross unrealized losses	3	2
Available-for-sale, fair value	1,272	1,548
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,734	3,371
Available for sale, gross unrealized gains	23	72
Available for sale, gross unrealized losses	13	0
Available-for-sale, fair value	2,744	3,443
Total before money market mutual fund liquidity facility
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	42,430	48,931
Held to maturity, gross unrealized gains	442	1,169
Held to maturity, gross unrealized losses	601	97
Investment securities held-to-maturity	42,271	50,003
Held-to-maturity under money market mutual fund liquidity facility
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	0	3,300
Held to maturity, gross unrealized gains	0	4
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	0	3,304
Debt securities, held-to-maturity, allowance for credit loss	0	1
Including money market mutual fund liquidity facility
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	42,430	52,231
Held to maturity, gross unrealized gains	442	1,173
Held to maturity, gross unrealized losses	601	97
Investment securities held-to-maturity	42,271	53,307
Non-US Collateralized Loan Obiligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	830	960
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 1,530	1,880
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%
State and political subdivisions, securities in trusts
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Investment securities related to state and political subdivisions	$ 520	700
Debt Security, Corporate, US
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,440	3,440
Non-Agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	292	464
Non-Agency RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	$ 14	$ 90