Investment Securities - Schedule of Marketable Securities (Details) - USD ($)	9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 42,377,000,000		$ 41,858,000,000
Available for sale, gross unrealized gains	19,000,000		14,000,000
Available for sale, gross unrealized losses	850,000,000		1,293,000,000
Available-for-sale, fair value	41,546,000,000		40,579,000,000
Held to maturity, amortized cost	61,956,000,000		64,700,000,000
Investment securities held-to-maturity	54,121,000,000		57,913,000,000
Allowance for credit losses on available-for-sale securities	0	$ 0	2,000,000	$ 1,000,000	$ 2,000,000	$ 2,000,000
Direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	7,812,000,000		8,232,000,000
Available for sale, gross unrealized gains	12,000,000		10,000,000
Available for sale, gross unrealized losses	197,000,000		261,000,000
Available-for-sale, fair value	7,627,000,000		7,981,000,000
Held to maturity, amortized cost	11,758,000,000		11,693,000,000
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	289,000,000		341,000,000
Investment securities held-to-maturity	11,469,000,000		11,352,000,000
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,266,000,000		8,767,000,000
Available for sale, gross unrealized gains	0		2,000,000
Available for sale, gross unrealized losses	280,000,000		260,000,000
Available-for-sale, fair value	9,986,000,000		8,509,000,000
Held to maturity, amortized cost	40,297,000,000		42,307,000,000
Held to maturity, gross unrealized gains	0		3,000,000
Held to maturity, gross unrealized losses	7,232,000,000		6,030,000,000
Investment securities held-to-maturity	33,065,000,000		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	18,078,000,000		16,999,000,000
Available for sale, gross unrealized gains	12,000,000		12,000,000
Available for sale, gross unrealized losses	477,000,000		521,000,000
Available-for-sale, fair value	17,613,000,000		16,490,000,000
Held to maturity, amortized cost	52,055,000,000		54,000,000,000
Held to maturity, gross unrealized gains	0		3,000,000
Held to maturity, gross unrealized losses	7,521,000,000		6,371,000,000
Investment securities held-to-maturity	44,534,000,000		47,632,000,000
Mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,551,000,000		1,642,000,000
Available for sale, gross unrealized gains	1,000,000		0
Available for sale, gross unrealized losses	11,000,000		19,000,000
Available-for-sale, fair value	1,541,000,000		1,623,000,000
Asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,903,000,000		1,696,000,000
Available for sale, gross unrealized gains	1,000,000		0
Available for sale, gross unrealized losses	14,000,000		27,000,000
Available-for-sale, fair value	1,890,000,000		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	14,910,000,000		14,512,000,000
Available for sale, gross unrealized gains	2,000,000		1,000,000
Available for sale, gross unrealized losses	246,000,000		424,000,000
Available-for-sale, fair value	14,666,000,000		14,089,000,000
Held to maturity, amortized cost	6,452,000,000		6,603,000,000
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	262,000,000		304,000,000
Investment securities held-to-maturity	6,190,000,000		6,299,000,000
Other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,085,000,000		2,255,000,000
Available for sale, gross unrealized gains	1,000,000		0
Available for sale, gross unrealized losses	64,000,000		164,000,000
Available-for-sale, fair value	2,022,000,000		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	20,449,000,000		20,105,000,000
Available for sale, gross unrealized gains	5,000,000		1,000,000
Available for sale, gross unrealized losses	335,000,000		634,000,000
Available-for-sale, fair value	20,119,000,000		19,472,000,000
Held to maturity, amortized cost	6,452,000,000		6,603,000,000
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	262,000,000		304,000,000
Investment securities held-to-maturity	6,190,000,000		6,299,000,000
Student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	118,000,000		116,000,000
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	0		1,000,000
Available-for-sale, fair value	118,000,000		115,000,000
Held to maturity, amortized cost	3,442,000,000		3,955,000,000
Held to maturity, gross unrealized gains	3,000,000		1,000,000
Held to maturity, gross unrealized losses	73,000,000		134,000,000
Investment securities held-to-maturity	3,372,000,000		3,822,000,000
Collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,649,000,000		2,394,000,000
Available for sale, gross unrealized gains	2,000,000		0
Available for sale, gross unrealized losses	11,000,000		39,000,000
Available-for-sale, fair value	2,640,000,000		2,355,000,000
Non-agency CMBS and RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	268,000,000		237,000,000
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	4,000,000		6,000,000
Available-for-sale, fair value	264,000,000		231,000,000
Held to maturity, amortized cost	7,000,000		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	25,000,000		160,000,000
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	0		0
Available for sale, gross unrealized losses	0		2,000,000
Available-for-sale, fair value	90,000,000		88,000,000
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,125,000,000		2,837,000,000
Available for sale, gross unrealized gains	2,000,000		0
Available for sale, gross unrealized losses	15,000,000		48,000,000
Available-for-sale, fair value	3,112,000,000		2,789,000,000
Held to maturity, amortized cost	3,449,000,000		4,097,000,000
Held to maturity, gross unrealized gains	21,000,000		19,000,000
Held to maturity, gross unrealized losses	73,000,000		134,000,000
Investment securities held-to-maturity	3,397,000,000		3,982,000,000
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	387,000,000		839,000,000
Available for sale, gross unrealized gains	0		1,000,000
Available for sale, gross unrealized losses	10,000,000		17,000,000
Available-for-sale, fair value	377,000,000		823,000,000
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	338,000,000		1,078,000,000
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	13,000,000		73,000,000
Available-for-sale, fair value	325,000,000		1,005,000,000
Including MMLF
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	61,956,000,000		64,700,000,000
Held to maturity, gross unrealized gains	21,000,000		22,000,000
Held to maturity, gross unrealized losses	7,856,000,000		6,809,000,000
Investment securities held-to-maturity	54,121,000,000		57,913,000,000
Non-US collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	970,000,000		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	1,670,000,000		1,140,000,000
US debt securities, corporate bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	330,000,000		1,010,000,000.00
Non-agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost	$ 7,000,000		133,000,000
Non-agency RMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Held to maturity, amortized cost			9,000,000
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%
Agency CMBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 5,630,000,000		6,780,000,000
Held to maturity, amortized cost	5,240,000,000		4,990,000,000
Agency MBS
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 4,360,000,000		$ 1,730,000,000