Investment Securities - Schedule of Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 66,973,000,000	$ 59,006,000,000
Available for sale, gross unrealized gains	278,000,000	172,000,000
Available for sale, gross unrealized losses	97,000,000	283,000,000
Available-for-sale investment securities:	67,154,000,000	58,895,000,000
Held to maturity, amortized cost	38,171,000,000	47,727,000,000
Investment securities held-to-maturity	34,166,000,000	41,906,000,000
Debt securities, AFS, allowance	0	0
Debt securities, HTM, allowance		0	$ 1,000,000
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	38,760,000,000	34,238,000,000
Available for sale, gross unrealized gains	145,000,000	59,000,000
Available for sale, gross unrealized losses	59,000,000	206,000,000
Available-for-sale investment securities:	38,846,000,000	34,091,000,000
Held to maturity, amortized cost	33,449,000,000	41,518,000,000
Held to maturity, gross unrealized gains	9,000,000	2,000,000
Held to maturity, gross unrealized losses	3,968,000,000	5,732,000,000
Investment securities held-to-maturity	29,490,000,000	35,788,000,000
US Treasury and federal agencies, direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	23,210,000,000	23,539,000,000
Available for sale, gross unrealized gains	55,000,000	38,000,000
Available for sale, gross unrealized losses	5,000,000	52,000,000
Available-for-sale investment securities:	23,260,000,000	23,525,000,000
Held to maturity, amortized cost	573,000,000	5,417,000,000
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	3,000,000	55,000,000
Investment securities held-to-maturity	570,000,000	5,362,000,000
US Treasury and federal agencies, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	15,550,000,000	10,699,000,000
Available for sale, gross unrealized gains	90,000,000	21,000,000
Available for sale, gross unrealized losses	54,000,000	154,000,000
Available-for-sale investment securities:	15,586,000,000	10,566,000,000
Held to maturity, amortized cost	32,876,000,000	36,101,000,000
Held to maturity, gross unrealized gains	9,000,000	2,000,000
Held to maturity, gross unrealized losses	3,965,000,000	5,677,000,000
Investment securities held-to-maturity	28,920,000,000	30,426,000,000
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	25,131,000,000	21,032,000,000
Available for sale, gross unrealized gains	126,000,000	102,000,000
Available for sale, gross unrealized losses	37,000,000	76,000,000
Available-for-sale investment securities:	25,220,000,000	21,058,000,000
Held to maturity, amortized cost	2,461,000,000	3,673,000,000
Held to maturity, gross unrealized gains	4,000,000	7,000,000
Held to maturity, gross unrealized losses	31,000,000	73,000,000
Investment securities held-to-maturity	2,434,000,000	3,607,000,000
Non-U.S. debt securities, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,573,000,000	2,426,000,000
Available for sale, gross unrealized gains	6,000,000	5,000,000
Available for sale, gross unrealized losses	1,000,000	1,000,000
Available-for-sale investment securities:	2,578,000,000	2,430,000,000
Non-U.S. debt securities, asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,081,000,000	1,865,000,000
Available for sale, gross unrealized gains	5,000,000	5,000,000
Available for sale, gross unrealized losses	1,000,000	2,000,000
Available-for-sale investment securities:	2,085,000,000	1,868,000,000
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	17,693,000,000	13,954,000,000
Available for sale, gross unrealized gains	73,000,000	54,000,000
Available for sale, gross unrealized losses	35,000,000	69,000,000
Available-for-sale investment securities:	17,731,000,000	13,939,000,000
Held to maturity, amortized cost	2,461,000,000	3,673,000,000
Held to maturity, gross unrealized gains	4,000,000	7,000,000
Held to maturity, gross unrealized losses	31,000,000	73,000,000
Investment securities held-to-maturity	2,434,000,000	3,607,000,000
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,784,000,000	2,787,000,000
Available for sale, gross unrealized gains	42,000,000	38,000,000
Available for sale, gross unrealized losses	0	4,000,000
Available-for-sale investment securities:	2,826,000,000	2,821,000,000
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,057,000,000	3,627,000,000
Available for sale, gross unrealized gains	7,000,000	11,000,000
Available for sale, gross unrealized losses	1,000,000	0
Available-for-sale investment securities:	3,063,000,000	3,638,000,000
Held to maturity, amortized cost	2,261,000,000	2,536,000,000
Held to maturity, gross unrealized gains	5,000,000	4,000,000
Held to maturity, gross unrealized losses	24,000,000	29,000,000
Investment securities held-to-maturity	2,242,000,000	2,511,000,000
Asset-backed securities, student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	63,000,000	89,000,000
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:	64,000,000	90,000,000
Held to maturity, amortized cost	2,261,000,000	2,536,000,000
Held to maturity, gross unrealized gains	5,000,000	4,000,000
Held to maturity, gross unrealized losses	24,000,000	29,000,000
Investment securities held-to-maturity	2,242,000,000	2,511,000,000
Asset-backed securities, collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,904,000,000	3,447,000,000
Available for sale, gross unrealized gains	2,000,000	6,000,000
Available for sale, gross unrealized losses	1,000,000	0
Available-for-sale investment securities:	2,905,000,000	3,453,000,000
Asset-backed securities, non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	0	1,000,000
Available for sale, gross unrealized gains	3,000,000	3,000,000
Available for sale, gross unrealized losses	0	0
Available-for-sale investment securities:	3,000,000	4,000,000
Asset-backed securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	90,000,000	90,000,000
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:	91,000,000	91,000,000
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	25,000,000	56,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	0
Available-for-sale investment securities:	25,000,000	56,000,000
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	0	53,000,000
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	1,000,000
Available-for-sale investment securities:	0	52,000,000
Total held-to-maturity securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	38,171,000,000	47,727,000,000
Held to maturity, gross unrealized gains	18,000,000	13,000,000
Held to maturity, gross unrealized losses	4,023,000,000	5,834,000,000
Investment securities held-to-maturity	34,166,000,000	41,906,000,000
Debt securities, HTM, allowance	1,000,000	1,000,000
Agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,810,000,000	4,360,000,000
Held to maturity, amortized cost	5,080,000,000.00	5,180,000,000
Agency MBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	12,780,000,000	6,200,000,000
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	770,000,000	700,000,000
Non-U.S. debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 2,400,000,000	$ 2,540,000,000
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%