Investment Securities - Amortized Costs, Fair Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Available-for-sale securities
Amortized cost	$ 216,188,000,000	$ 308,254,000,000
Gross unrealized gains	890,000,000	2,614,000,000
Gross unrealized losses	11,221,000,000	2,343,000,000
Fair value	205,857,000,000	308,525,000,000
Held-to-maturity securities
Amortized cost	425,305,000,000	363,707,000,000
Gross unrealized gains	105,000,000	2,110,000,000
Gross unrealized losses	36,762,000,000	3,189,000,000
Fair value	388,648,000,000	362,628,000,000
Total investment securities, net of allowance for credit losses
Amortized cost	641,493,000,000	671,961,000,000
Gross unrealized gains	995,000,000	4,724,000,000
Gross unrealized losses	47,983,000,000	5,532,000,000
Fair value	594,505,000,000	671,153,000,000
HTM securities purchased	33,700,000,000	111,800,000,000	$ 12,400,000,000
Allowance for credit losses on investment securities	96,000,000	42,000,000	$ 78,000,000
Accrued interest receivables on investment securities	2,500,000,000	1,900,000,000
Accrued interest receivables reversed through interest income on HTM securities	0	0
Accrued interest receivables reversed through interest income on AFS securities	0	0
Total mortgage-backed securities
Available-for-sale securities
Amortized cost	84,059,000,000	83,754,000,000
Gross unrealized gains	485,000,000	821,000,000
Gross unrealized losses	6,463,000,000	1,013,000,000
Fair value	78,081,000,000	83,562,000,000
Held-to-maturity securities
Amortized cost	134,356,000,000	113,602,000,000
Gross unrealized gains	48,000,000	1,412,000,000
Gross unrealized losses	15,687,000,000	1,013,000,000
Fair value	118,717,000,000	114,001,000,000
U.S. GSEs and government agencies
Available-for-sale securities
Amortized cost	77,194,000,000	72,800,000,000
Gross unrealized gains	479,000,000	736,000,000
Gross unrealized losses	6,170,000,000	993,000,000
Fair value	71,503,000,000	72,543,000,000
Held-to-maturity securities
Amortized cost	113,492,000,000	102,556,000,000
Gross unrealized gains	35,000,000	1,400,000,000
Gross unrealized losses	13,709,000,000	853,000,000
Fair value	99,818,000,000	103,103,000,000
Residential: U.S.
Available-for-sale securities
Amortized cost	1,576,000,000	2,128,000,000
Gross unrealized gains	1,000,000	38,000,000
Gross unrealized losses	111,000,000	2,000,000
Fair value	1,466,000,000	2,164,000,000
Held-to-maturity securities
Amortized cost	10,503,000,000	7,316,000,000
Gross unrealized gains	3,000,000	1,000,000
Gross unrealized losses	1,244,000,000	106,000,000
Fair value	9,262,000,000	7,211,000,000
Residential: Non-U.S.
Available-for-sale securities
Amortized cost	3,176,000,000	3,882,000,000
Gross unrealized gains	5,000,000	25,000,000
Gross unrealized losses	27,000,000	1,000,000
Fair value	3,154,000,000	3,906,000,000
Commercial
Available-for-sale securities
Amortized cost	2,113,000,000	4,944,000,000
Gross unrealized gains	0	22,000,000
Gross unrealized losses	155,000,000	17,000,000
Fair value	1,958,000,000	4,949,000,000
Held-to-maturity securities
Amortized cost	10,361,000,000	3,730,000,000
Gross unrealized gains	10,000,000	11,000,000
Gross unrealized losses	734,000,000	54,000,000
Fair value	9,637,000,000	3,687,000,000
U.S. Treasury and government agencies
Available-for-sale securities
Amortized cost	95,217,000,000	178,038,000,000
Gross unrealized gains	302,000,000	668,000,000
Gross unrealized losses	3,459,000,000	1,243,000,000
Fair value	92,060,000,000	177,463,000,000
Held-to-maturity securities
Amortized cost	207,463,000,000	185,204,000,000
Gross unrealized gains	0	169,000,000
Gross unrealized losses	18,363,000,000	2,103,000,000
Fair value	189,100,000,000	183,270,000,000
Obligations of U.S. states and municipalities
Available-for-sale securities
Amortized cost	7,103,000,000	14,890,000,000
Gross unrealized gains	86,000,000	972,000,000
Gross unrealized losses	403,000,000	2,000,000
Fair value	6,786,000,000	15,860,000,000
Held-to-maturity securities
Amortized cost	19,747,000,000	13,985,000,000
Gross unrealized gains	53,000,000	453,000,000
Gross unrealized losses	1,080,000,000	44,000,000
Fair value	18,720,000,000	14,394,000,000
Non-U.S. government debt securities
Available-for-sale securities
Amortized cost	20,360,000,000	16,163,000,000
Gross unrealized gains	14,000,000	92,000,000
Gross unrealized losses	678,000,000	46,000,000
Fair value	19,696,000,000	16,209,000,000
Corporate debt securities
Available-for-sale securities
Amortized cost	381,000,000	332,000,000
Gross unrealized gains	0	8,000,000
Gross unrealized losses	24,000,000	19,000,000
Fair value	357,000,000	321,000,000
Asset-backed securities: Collateralized loan obligations
Available-for-sale securities
Amortized cost	5,916,000,000	9,674,000,000
Gross unrealized gains	1,000,000	6,000,000
Gross unrealized losses	125,000,000	18,000,000
Fair value	5,792,000,000	9,662,000,000
Held-to-maturity securities
Amortized cost	61,414,000,000	48,869,000,000
Gross unrealized gains	4,000,000	75,000,000
Gross unrealized losses	1,522,000,000	22,000,000
Fair value	59,896,000,000	48,922,000,000
Asset-backed securities: Other
Available-for-sale securities
Amortized cost	3,152,000,000	5,403,000,000
Gross unrealized gains	2,000,000	47,000,000
Gross unrealized losses	69,000,000	2,000,000
Fair value	3,085,000,000	5,448,000,000
Held-to-maturity securities
Amortized cost	2,325,000,000	2,047,000,000
Gross unrealized gains	0	1,000,000
Gross unrealized losses	110,000,000	7,000,000
Fair value	$ 2,215,000,000	$ 2,041,000,000