Investment Securities - Schedule of Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 59,006,000,000	$ 44,853,000,000
Available for sale, gross unrealized gains	172,000,000	209,000,000
Available for sale, gross unrealized losses	283,000,000	536,000,000
Available-for-sale investment securities:	58,895,000,000	44,526,000,000
Held to maturity, amortized cost	47,727,000,000	57,117,000,000
Investment securities held-to-maturity	41,906,000,000	51,503,000,000
Debt securities, HTM, allowance	0	1,000,000	$ 0
US Treasury and federal agencies, direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	23,539,000,000	8,427,000,000
Available for sale, gross unrealized gains	38,000,000	39,000,000
Available for sale, gross unrealized losses	52,000,000	165,000,000
Available-for-sale investment securities:	23,525,000,000	8,301,000,000
Held to maturity, amortized cost	5,417,000,000	8,584,000,000
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	55,000,000	163,000,000
Investment securities held-to-maturity	5,362,000,000	8,421,000,000
US Treasury and federal agencies, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,699,000,000	10,870,000,000
Available for sale, gross unrealized gains	21,000,000	49,000,000
Available for sale, gross unrealized losses	154,000,000	164,000,000
Available-for-sale investment securities:	10,566,000,000	10,755,000,000
Held to maturity, amortized cost	36,101,000,000	39,472,000,000
Held to maturity, gross unrealized gains	2,000,000	7,000,000
Held to maturity, gross unrealized losses	5,677,000,000	5,271,000,000
Investment securities held-to-maturity	30,426,000,000	34,208,000,000
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	34,238,000,000	19,297,000,000
Available for sale, gross unrealized gains	59,000,000	88,000,000
Available for sale, gross unrealized losses	206,000,000	329,000,000
Available-for-sale investment securities:	34,091,000,000	19,056,000,000
Held to maturity, amortized cost	41,518,000,000	48,056,000,000
Held to maturity, gross unrealized gains	2,000,000	7,000,000
Held to maturity, gross unrealized losses	5,732,000,000	5,434,000,000
Investment securities held-to-maturity	35,788,000,000	42,629,000,000
Non-U.S. debt securities, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,426,000,000	1,861,000,000
Available for sale, gross unrealized gains	5,000,000	3,000,000
Available for sale, gross unrealized losses	1,000,000	7,000,000
Available-for-sale investment securities:	2,430,000,000	1,857,000,000
Non-U.S. debt securities, asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,865,000,000	2,148,000,000
Available for sale, gross unrealized gains	5,000,000	2,000,000
Available for sale, gross unrealized losses	2,000,000	13,000,000
Available-for-sale investment securities:	1,868,000,000	2,137,000,000
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	13,954,000,000	15,159,000,000
Available for sale, gross unrealized gains	54,000,000	73,000,000
Available for sale, gross unrealized losses	69,000,000	132,000,000
Available-for-sale investment securities:	13,939,000,000	15,100,000,000
Held to maturity, amortized cost	3,673,000,000	5,757,000,000
Held to maturity, gross unrealized gains	7,000,000	8,000,000
Held to maturity, gross unrealized losses	73,000,000	153,000,000
Investment securities held-to-maturity	3,607,000,000	5,612,000,000
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,787,000,000	2,733,000,000
Available for sale, gross unrealized gains	38,000,000	39,000,000
Available for sale, gross unrealized losses	4,000,000	37,000,000
Available-for-sale investment securities:	2,821,000,000	2,735,000,000
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	21,032,000,000	21,901,000,000
Available for sale, gross unrealized gains	102,000,000	117,000,000
Available for sale, gross unrealized losses	76,000,000	189,000,000
Available-for-sale investment securities:	21,058,000,000	21,829,000,000
Held to maturity, amortized cost	3,673,000,000	5,757,000,000
Held to maturity, gross unrealized gains	7,000,000	8,000,000
Held to maturity, gross unrealized losses	73,000,000	153,000,000
Investment securities held-to-maturity	3,607,000,000	5,612,000,000
Asset-backed securities, student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	89,000,000	113,000,000
Available for sale, gross unrealized gains	1,000,000	1,000,000
Available for sale, gross unrealized losses	0	0
Available-for-sale investment securities:	90,000,000	114,000,000
Held to maturity, amortized cost	2,536,000,000	3,298,000,000
Held to maturity, gross unrealized gains	4,000,000	2,000,000
Held to maturity, gross unrealized losses	29,000,000	62,000,000
Investment securities held-to-maturity	2,511,000,000	3,238,000,000
Asset-backed securities, collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,447,000,000	90,000,000
Available for sale, gross unrealized gains	6,000,000	0
Available for sale, gross unrealized losses	0	0
Available-for-sale investment securities:	3,453,000,000	90,000,000
Asset-backed securities, non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,000,000	252,000,000
Available for sale, gross unrealized gains	3,000,000	0
Available for sale, gross unrealized losses	0	3,000,000
Available-for-sale investment securities:	4,000,000	249,000,000
Held to maturity, amortized cost	0	6,000,000
Held to maturity, gross unrealized gains	0	18,000,000
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	0	24,000,000
Asset-backed securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	90,000,000	2,530,000,000
Available for sale, gross unrealized gains	1,000,000	3,000,000
Available for sale, gross unrealized losses	0	6,000,000
Available-for-sale investment securities:	91,000,000	2,527,000,000
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,627,000,000	2,985,000,000
Available for sale, gross unrealized gains	11,000,000	4,000,000
Available for sale, gross unrealized losses	0	9,000,000
Available-for-sale investment securities:	3,638,000,000	2,980,000,000
Held to maturity, amortized cost	2,536,000,000	3,304,000,000
Held to maturity, gross unrealized gains	4,000,000	20,000,000
Held to maturity, gross unrealized losses	29,000,000	62,000,000
Investment securities held-to-maturity	2,511,000,000	3,262,000,000
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	56,000,000	356,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	1,000,000
Available-for-sale investment securities:	56,000,000	355,000,000
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	53,000,000	314,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	1,000,000	8,000,000
Available-for-sale investment securities:	52,000,000	306,000,000
Including money market mutual fund liquidity facility
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	47,727,000,000	57,117,000,000
Held to maturity, gross unrealized gains	13,000,000	35,000,000
Held to maturity, gross unrealized losses	5,834,000,000	5,649,000,000
Investment securities held-to-maturity	41,906,000,000	51,503,000,000
Agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	4,360,000,000	5,540,000,000
Held to maturity, amortized cost	5,180,000,000	5,230,000,000
Agency MBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	6,200,000,000	5,210,000,000
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	700,000,000	1,020,000,000.00
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 2,540,000,000	2,360,000,000
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	$ 50,000,000.00	$ 310,000,000