Investment Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 42,363	$ 73,440
Available for sale, gross unrealized gains	15	404
Available for sale, gross unrealized losses	1,392	445
Available-for-sale, fair value	40,986	73,399
Held to maturity, amortized cost	65,232	42,430
Investment securities held-to-maturity	58,320	42,271
Allowance for credit losses on available-for-sale securities	1	2
Direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	8,150	18,111
Available for sale, gross unrealized gains	13	24
Available for sale, gross unrealized losses	307	196
Available-for-sale, fair value	7,856	17,939
Held to maturity, amortized cost	11,637	2,170
Held to maturity, gross unrealized gains	0	10
Held to maturity, gross unrealized losses	353	0
Investment securities held-to-maturity	11,284	2,180
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	9,618	18,154
Available for sale, gross unrealized gains	0	148
Available for sale, gross unrealized losses	215	94
Available-for-sale, fair value	9,403	18,208
Held to maturity, amortized cost	42,967	33,481
Held to maturity, gross unrealized gains	0	362
Held to maturity, gross unrealized losses	6,207	578
Investment securities held-to-maturity	36,760	33,265
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	17,768	36,265
Available for sale, gross unrealized gains	13	172
Available for sale, gross unrealized losses	522	290
Available-for-sale, fair value	17,259	36,147
Held to maturity, amortized cost	54,604	35,651
Held to maturity, gross unrealized gains	0	372
Held to maturity, gross unrealized losses	6,560	578
Investment securities held-to-maturity	48,044	35,445
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,680	1,986
Available for sale, gross unrealized gains	0	12
Available for sale, gross unrealized losses	18	3
Available-for-sale, fair value	1,662	1,995
Asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,671	2,087
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	31	2
Available-for-sale, fair value	1,640	2,087
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	14,142	23,533
Available for sale, gross unrealized gains	2	114
Available for sale, gross unrealized losses	470	100
Available-for-sale, fair value	13,674	23,547
Held to maturity, amortized cost	6,141	1,564
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	268	9
Investment securities held-to-maturity	5,873	1,555
Other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,262	3,113
Available for sale, gross unrealized gains	0	17
Available for sale, gross unrealized losses	178	32
Available-for-sale, fair value	2,084	3,098
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	19,755	30,719
Available for sale, gross unrealized gains	2	145
Available for sale, gross unrealized losses	697	137
Available-for-sale, fair value	19,060	30,727
Held to maturity, amortized cost	6,141	1,564
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	268	9
Investment securities held-to-maturity	5,873	1,555
Student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	134	209
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	1	0
Available-for-sale, fair value	133	211
Held to maturity, amortized cost	4,238	4,908
Held to maturity, gross unrealized gains	1	48
Held to maturity, gross unrealized losses	104	14
Investment securities held-to-maturity	4,135	4,942
Collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,371	2,155
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	54	2
Available-for-sale, fair value	2,317	2,155
Non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	220	52
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	5	0
Available-for-sale, fair value	215	52
Held to maturity, amortized cost	249	307
Held to maturity, gross unrealized gains	19	22
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	268	329
Other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	90	90
Available for sale, gross unrealized gains	0	1
Available for sale, gross unrealized losses	2	0
Available-for-sale, fair value	88	91
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,815	2,506
Available for sale, gross unrealized gains	0	5
Available for sale, gross unrealized losses	62	2
Available-for-sale, fair value	2,753	2,509
Held to maturity, amortized cost	4,487	5,215
Held to maturity, gross unrealized gains	20	70
Held to maturity, gross unrealized losses	104	14
Investment securities held-to-maturity	4,403	5,271
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	952	1,216
Available for sale, gross unrealized gains	0	59
Available for sale, gross unrealized losses	28	3
Available-for-sale, fair value	924	1,272
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,073	2,734
Available for sale, gross unrealized gains	0	23
Available for sale, gross unrealized losses	83	13
Available-for-sale, fair value	990	2,744
Including MMLF
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	65,232	42,430
Held to maturity, gross unrealized gains	20	442
Held to maturity, gross unrealized losses	6,932	601
Investment securities held-to-maturity	58,320	42,271
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	780	830
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,110	1,530
US debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	990	2,440
Non-agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	239	292
Non-agency RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	$ 10	$ 14
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%