Investment Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 46,596	$ 73,440
Available for sale, gross unrealized gains	21	404
Available for sale, gross unrealized losses	1,162	445
Available-for-sale, fair value	45,454	73,399
Held to maturity, amortized cost	64,261	42,430
Investment securities held-to-maturity	60,103	42,271
Allowance for credit losses on available-for-sale securities	2	2
Direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	9,720	18,111
Available for sale, gross unrealized gains	12	24
Available for sale, gross unrealized losses	321	196
Available-for-sale, fair value	9,411	17,939
Held to maturity, amortized cost	11,424	2,170
Held to maturity, gross unrealized gains	0	10
Held to maturity, gross unrealized losses	75	0
Investment securities held-to-maturity	11,349	2,180
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,409	18,154
Available for sale, gross unrealized gains	1	148
Available for sale, gross unrealized losses	139	94
Available-for-sale, fair value	10,271	18,208
Held to maturity, amortized cost	41,660	33,481
Held to maturity, gross unrealized gains	2	362
Held to maturity, gross unrealized losses	3,854	578
Investment securities held-to-maturity	37,808	33,265
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	20,129	36,265
Available for sale, gross unrealized gains	13	172
Available for sale, gross unrealized losses	460	290
Available-for-sale, fair value	19,682	36,147
Held to maturity, amortized cost	53,084	35,651
Held to maturity, gross unrealized gains	2	372
Held to maturity, gross unrealized losses	3,929	578
Investment securities held-to-maturity	49,157	35,445
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,972	1,986
Available for sale, gross unrealized gains	5	12
Available for sale, gross unrealized losses	18	3
Available-for-sale, fair value	1,959	1,995
Asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,901	2,087
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	25	2
Available-for-sale, fair value	1,876	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	15,300	23,533
Available for sale, gross unrealized gains	1	114
Available for sale, gross unrealized losses	374	100
Available-for-sale, fair value	14,927	23,547
Held to maturity, amortized cost	6,443	1,564
Held to maturity, gross unrealized gains	5	0
Held to maturity, gross unrealized losses	133	9
Investment securities held-to-maturity	6,315	1,555
Other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,358	3,113
Available for sale, gross unrealized gains	0	17
Available for sale, gross unrealized losses	154	32
Available-for-sale, fair value	2,204	3,098
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	21,531	30,719
Available for sale, gross unrealized gains	6	145
Available for sale, gross unrealized losses	571	137
Available-for-sale, fair value	20,966	30,727
Held to maturity, amortized cost	6,443	1,564
Held to maturity, gross unrealized gains	5	0
Held to maturity, gross unrealized losses	133	9
Investment securities held-to-maturity	6,315	1,555
Student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	152	209
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	2	0
Available-for-sale, fair value	150	211
Held to maturity, amortized cost	4,468	4,908
Held to maturity, gross unrealized gains	1	48
Held to maturity, gross unrealized losses	124	14
Investment securities held-to-maturity	4,345	4,942
Collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,378	2,155
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	43	2
Available-for-sale, fair value	2,334	2,155
Non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	200	52
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	5	0
Available-for-sale, fair value	195	52
Held to maturity, amortized cost	266	307
Held to maturity, gross unrealized gains	20	22
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	286	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	1	0
Available-for-sale, fair value	89	91
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,820	2,506
Available for sale, gross unrealized gains	0	5
Available for sale, gross unrealized losses	51	2
Available-for-sale, fair value	2,768	2,509
Held to maturity, amortized cost	4,734	5,215
Held to maturity, gross unrealized gains	21	70
Held to maturity, gross unrealized losses	124	14
Investment securities held-to-maturity	4,631	5,271
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,042	1,216
Available for sale, gross unrealized gains	2	59
Available for sale, gross unrealized losses	10	3
Available-for-sale, fair value	1,034	1,272
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,074	2,734
Available for sale, gross unrealized gains	0	23
Available for sale, gross unrealized losses	70	13
Available-for-sale, fair value	1,004	2,744
Including MMLF
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	64,261	42,430
Held to maturity, gross unrealized gains	28	442
Held to maturity, gross unrealized losses	4,186	601
Investment securities held-to-maturity	60,103	42,271
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	850	830
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 1,100	1,530
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%
US debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 1,000	2,440
Non-agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	256	292
Non-agency RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	$ 11	$ 14