Investment Securities - Schedule of Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 44,853,000,000	$ 41,858,000,000
Available for sale, gross unrealized gains	209,000,000	14,000,000
Available for sale, gross unrealized losses	536,000,000	1,293,000,000
Available-for-sale investment securities:	44,526,000,000	40,579,000,000
Held to maturity, amortized cost	57,117,000,000	64,700,000,000
Investment securities held-to-maturity	51,503,000,000	57,913,000,000
Debt securities, AFS, allowance	0	2,000,000	$ 2,000,000
Debt securities, HTM, allowance	1,000,000	0	$ 0
Asset Pledged as Collateral
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Pledged securities not separately reported	71,300,000,000	70,520,000,000
US Treasury and federal agencies, direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	8,427,000,000	8,232,000,000
Available for sale, gross unrealized gains	39,000,000	10,000,000
Available for sale, gross unrealized losses	165,000,000	261,000,000
Available-for-sale investment securities:	8,301,000,000	7,981,000,000
Held to maturity, amortized cost	8,584,000,000	11,693,000,000
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	163,000,000	341,000,000
Investment securities held-to-maturity	8,421,000,000	11,352,000,000
US Treasury and federal agencies, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,870,000,000	8,767,000,000
Available for sale, gross unrealized gains	49,000,000	2,000,000
Available for sale, gross unrealized losses	164,000,000	260,000,000
Available-for-sale investment securities:	10,755,000,000	8,509,000,000
Held to maturity, amortized cost	39,472,000,000	42,307,000,000
Held to maturity, gross unrealized gains	7,000,000	3,000,000
Held to maturity, gross unrealized losses	5,271,000,000	6,030,000,000
Investment securities held-to-maturity	34,208,000,000	36,280,000,000
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	19,297,000,000	16,999,000,000
Available for sale, gross unrealized gains	88,000,000	12,000,000
Available for sale, gross unrealized losses	329,000,000	521,000,000
Available-for-sale investment securities:	19,056,000,000	16,490,000,000
Held to maturity, amortized cost	48,056,000,000	54,000,000,000
Held to maturity, gross unrealized gains	7,000,000	3,000,000
Held to maturity, gross unrealized losses	5,434,000,000	6,371,000,000
Investment securities held-to-maturity	42,629,000,000	47,632,000,000
Non-U.S. debt securities, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,861,000,000	1,642,000,000
Available for sale, gross unrealized gains	3,000,000	0
Available for sale, gross unrealized losses	7,000,000	19,000,000
Available-for-sale investment securities:	1,857,000,000	1,623,000,000
Non-U.S. debt securities, asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,148,000,000	1,696,000,000
Available for sale, gross unrealized gains	2,000,000	0
Available for sale, gross unrealized losses	13,000,000	27,000,000
Available-for-sale investment securities:	2,137,000,000	1,669,000,000
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	15,159,000,000	14,512,000,000
Available for sale, gross unrealized gains	73,000,000	1,000,000
Available for sale, gross unrealized losses	132,000,000	424,000,000
Available-for-sale investment securities:	15,100,000,000	14,089,000,000
Held to maturity, amortized cost	5,757,000,000	6,603,000,000
Held to maturity, gross unrealized gains	8,000,000	0
Held to maturity, gross unrealized losses	153,000,000	304,000,000
Investment securities held-to-maturity	5,612,000,000	6,299,000,000
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,733,000,000	2,255,000,000
Available for sale, gross unrealized gains	39,000,000	0
Available for sale, gross unrealized losses	37,000,000	164,000,000
Available-for-sale investment securities:	2,735,000,000	2,091,000,000
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	21,901,000,000	20,105,000,000
Available for sale, gross unrealized gains	117,000,000	1,000,000
Available for sale, gross unrealized losses	189,000,000	634,000,000
Available-for-sale investment securities:	21,829,000,000	19,472,000,000
Held to maturity, amortized cost	5,757,000,000	6,603,000,000
Held to maturity, gross unrealized gains	8,000,000	0
Held to maturity, gross unrealized losses	153,000,000	304,000,000
Investment securities held-to-maturity	5,612,000,000	6,299,000,000
Asset-backed securities, student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	113,000,000	116,000,000
Available for sale, gross unrealized gains	1,000,000	0
Available for sale, gross unrealized losses	0	1,000,000
Available-for-sale investment securities:	114,000,000	115,000,000
Held to maturity, amortized cost	3,298,000,000	3,955,000,000
Held to maturity, gross unrealized gains	2,000,000	1,000,000
Held to maturity, gross unrealized losses	62,000,000	134,000,000
Investment securities held-to-maturity	3,238,000,000	3,822,000,000
Asset-backed securities, collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,530,000,000	90,000,000
Available for sale, gross unrealized gains	3,000,000	0
Available for sale, gross unrealized losses	6,000,000	2,000,000
Available-for-sale investment securities:	2,527,000,000	88,000,000
Asset-backed securities, non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	252,000,000	237,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	3,000,000	6,000,000
Available-for-sale investment securities:	249,000,000	231,000,000
Held to maturity, amortized cost	6,000,000	142,000,000
Held to maturity, gross unrealized gains	18,000,000	18,000,000
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	24,000,000	160,000,000
Asset-backed securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	90,000,000	2,394,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	39,000,000
Available-for-sale investment securities:	90,000,000	2,355,000,000
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,985,000,000	2,837,000,000
Available for sale, gross unrealized gains	4,000,000	0
Available for sale, gross unrealized losses	9,000,000	48,000,000
Available-for-sale investment securities:	2,980,000,000	2,789,000,000
Held to maturity, amortized cost	3,304,000,000	4,097,000,000
Held to maturity, gross unrealized gains	20,000,000	19,000,000
Held to maturity, gross unrealized losses	62,000,000	134,000,000
Investment securities held-to-maturity	3,262,000,000	3,982,000,000
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	356,000,000	839,000,000
Available for sale, gross unrealized gains	0	1,000,000
Available for sale, gross unrealized losses	1,000,000	17,000,000
Available-for-sale investment securities:	355,000,000	823,000,000
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	314,000,000	1,078,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	8,000,000	73,000,000
Available-for-sale investment securities:	306,000,000	1,005,000,000
Including money market mutual fund liquidity facility
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	57,117,000,000	64,700,000,000
Held to maturity, gross unrealized gains	35,000,000	22,000,000
Held to maturity, gross unrealized losses	5,649,000,000	6,809,000,000
Investment securities held-to-maturity	51,503,000,000	57,913,000,000
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,020,000,000.00	860,000,000
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 2,360,000,000	1,140,000,000
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 corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 310,000,000	1,010,000,000.00
Non-agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Debt securities, held-to-maturity, amortized cost, before allowance for credit loss	133,000,000	9,000,000
Agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	5,540,000,000	6,780,000,000
Held to maturity, amortized cost	5,230,000,000	4,990,000,000
Agency MBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 5,210,000,000	$ 1,730,000,000