FAIR VALUE MEASUREMENT - Items Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed and purchased under agreements to resell, Netting	$ (100,204)	$ (131,342)
Trading account assets	358,260	331,945
Netting agreements	(431,992)	(292,628)
Netting of cash collateral received	(34,709)	(24,447)
Trading derivatives	97,684	69,776
Investments	508,016	512,822
Loans held at fair value	3,879	6,082
Liabilities, Fair Value Disclosure [Abstract]
Federal funds purchased and securities loaned and sold under agreements to repurchase, Netting	(100,204)	(131,342)
Netting agreements	(431,992)	(292,628)
Netting of cash collateral paid	(44,172)	(29,306)
Total derivative liabilities	72,597	55,516
Fair Value Measured at Net Asset Value Per Share [Member]
Liabilities, Fair Value Disclosure [Abstract]
Investments measured at net asset value excluded from Level 3	100	100
Recurring
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed and purchased under agreements to resell	326,786	342,261
Federal funds sold and securities borrowed and purchased under agreements to resell, Netting	(97,767)	(125,795)
Federal funds sold and securities borrowed and purchased under agreements to resell	229,019	216,466
Investments	232,967	289,409
Loans held at fair value	3,879	6,082
Mortgage servicing rights	647	404
Assets before netting	1,399,187	1,299,518
Netting, Assets, total of netting agreements and cash collateral received	(564,468)	(442,870)
Total assets	834,719	856,648
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	2,440	1,666
Federal funds purchased and securities loaned and sold under agreements to repurchase, Gross	156,909	174,961
Federal funds purchased and securities loaned and sold under agreements to repurchase, Netting	(83,802)	(118,267)
Federal funds purchased and securities loaned and sold under agreements to repurchase	73,107	56,694
Securities sold, not yet purchased	123,878	106,008
Trading liabilities	123,882	106,013
Short-term borrowings	6,569	7,358
Long-term debt	91,825	82,609
Total liabilities, Gross	933,599	753,632
Total liabilities, Netting	(559,966)	(440,201)
Total liabilities	373,633	313,431
Recurring | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	548,761	377,450
Total trading derivatives and cash collateral, liability	548,761	377,450
Netting agreements	(431,992)	(292,628)
Netting of cash collateral paid	(44,172)	(29,306)
Netting, Liabilities, total of netting agreements and cash collateral received	(476,164)	(321,934)
Total derivative liabilities	72,597	55,516
Recurring | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	183,665	150,074
Recurring | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	249,318	135,298
Recurring | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	63,906	49,684
Recurring | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	42,530	31,379
Recurring | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	9,342	11,015
Recurring | Other financial liabilities measured on a recurring basis
Liabilities, Fair Value Disclosure [Abstract]
Netting of cash collateral paid		0
Netting, Liabilities, total of netting agreements and cash collateral received	0
Non-trading derivatives and other financial liabilities measured on a recurring basis, gross	3,213	3,575
Total other assets and cash collateral, gross	3,213	3,575
Recurring | Other trading liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	4	5
Recurring | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	33,118	36,637
Investments	11,811	33,621
Recurring | Mortgage securitizations - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	31,189	35,030
Investments	11,331	33,216
Recurring | Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	996	748
Investments	476	380
Recurring | Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	933	859
Investments	4	25
Recurring | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	80,482	48,134
Investments	89,663	122,440
Recurring | State and municipal
Assets, Fair Value Disclosure [Abstract]
Trading account assets	2,090	2,032
Investments	2,153	2,621
Recurring | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	69,425	70,684
Investments	118,971	118,740
Recurring | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	16,154	18,112
Investments	5,513	5,920
Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	41,080	64,054
Investments	431	543
Recurring | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	2,169	1,594
Investments	276	303
Recurring | Other trading assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	16,058	20,922
Investments	3,756	4,877
Recurring | Non-marketable equity securities
Assets, Fair Value Disclosure [Abstract]
Investments	393	344
Recurring | Trading non-derivative assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	260,576	262,169
Recurring | Trading account derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	564,385	386,851
Trading derivative, asset, gross net cash collateral paid	564,385	386,851
Netting agreements	(431,992)	(292,628)
Netting of cash collateral received	(34,709)	(24,447)
Total trading derivatives, netting	(466,701)	(317,075)
Trading derivatives	97,684	69,776
Recurring | Trading account derivatives | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	190,583	165,488
Recurring | Trading account derivatives | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	253,326	135,549
Recurring | Trading account derivatives | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	60,856	45,252
Recurring | Trading account derivatives | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	49,395	30,344
Recurring | Trading account derivatives | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	10,225	10,218
Recurring | Non-trading derivatives and other financial assets measured on a recurring basis
Assets, Fair Value Disclosure [Abstract]
Total trading derivatives, netting	0	0
Total other assets and cash collateral, gross	9,947	12,342
Other assets	9,947	12,342
Recurring | Level 1
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed and purchased under agreements to resell	0	0
Investments	144,001	182,324
Loans held at fair value	0	0
Mortgage servicing rights	0	0
Assets before netting	$ 302,048	$ 325,984
Total as a percentage of gross assets	21.60%	25.10%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 0	$ 0
Federal funds purchased and securities loaned and sold under agreements to repurchase, Gross	0	0
Securities sold, not yet purchased	108,425	82,675
Trading liabilities	108,425	82,675
Short-term borrowings	0	0
Long-term debt	0	0
Total liabilities, Gross	$ 111,931	$ 86,365
Total as a percentage of gross liabilities	12.00%	11.50%
Recurring | Level 1 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 442	$ 116
Recurring | Level 1 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	358	56
Recurring | Level 1 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	0	0
Recurring | Level 1 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	84	60
Recurring | Level 1 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	0	0
Recurring | Level 1 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	0	0
Recurring | Level 1 | Other financial liabilities measured on a recurring basis
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	3,064	3,574
Recurring | Level 1 | Other trading liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	0	0
Recurring | Level 1 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1	1
Investments	0	0
Recurring | Level 1 | Mortgage securitizations - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0
Investments	0	0
Recurring | Level 1 | Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1	1
Investments	0	0
Recurring | Level 1 | Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0
Investments	0	0
Recurring | Level 1 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	77,742	44,900
Investments	89,618	122,271
Recurring | Level 1 | State and municipal
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0
Investments	0	0
Recurring | Level 1 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	41,515	39,176
Investments	51,713	56,842
Recurring | Level 1 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,530	1,544
Investments	2,437	2,861
Recurring | Level 1 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	33,153	53,833
Investments	233	350
Recurring | Level 1 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	0
Investments	0	0
Recurring | Level 1 | Other trading assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1	0
Investments	0	0
Recurring | Level 1 | Non-marketable equity securities
Assets, Fair Value Disclosure [Abstract]
Investments	0	0
Recurring | Level 1 | Trading non-derivative assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	153,942	139,454
Recurring | Level 1 | Trading account derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	787	131
Recurring | Level 1 | Trading account derivatives | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	730	90
Recurring | Level 1 | Trading account derivatives | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	0	0
Recurring | Level 1 | Trading account derivatives | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	57	41
Recurring | Level 1 | Trading account derivatives | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	0	0
Recurring | Level 1 | Trading account derivatives | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	0	0
Recurring | Level 1 | Non-trading derivatives and other financial assets measured on a recurring basis
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	3,318	4,075
Recurring | Level 2
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed and purchased under agreements to resell	326,645	342,030
Investments	86,733	104,858
Loans held at fair value	3,244	5,371
Mortgage servicing rights	0	0
Assets before netting	$ 1,080,362	$ 958,810
Total as a percentage of gross assets	77.20%	73.80%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 2,424	$ 1,483
Federal funds purchased and securities loaned and sold under agreements to repurchase, Gross	155,912	174,318
Securities sold, not yet purchased	15,350	23,268
Trading liabilities	15,352	23,273
Short-term borrowings	6,534	7,253
Long-term debt	60,115	57,100
Total liabilities, Gross	$ 779,443	$ 632,091
Total as a percentage of gross liabilities	83.50%	83.90%
Recurring | Level 2 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 538,970	$ 368,664
Recurring | Level 2 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	179,520	147,846
Recurring | Level 2 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	248,737	134,572
Recurring | Level 2 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	61,530	46,177
Recurring | Level 2 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	41,377	30,004
Recurring | Level 2 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	7,806	10,065
Recurring | Level 2 | Other financial liabilities measured on a recurring basis
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	136	0
Recurring | Level 2 | Other trading liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	2	5
Recurring | Level 2 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	32,187	35,955
Investments	11,746	33,476
Recurring | Level 2 | Mortgage securitizations - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	30,517	34,534
Investments	11,305	33,165
Recurring | Level 2 | Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	853	643
Investments	437	286
Recurring | Level 2 | Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	817	778
Investments	4	25
Recurring | Level 2 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	2,740	3,230
Investments	45	168
Recurring | Level 2 | State and municipal
Assets, Fair Value Disclosure [Abstract]
Trading account assets	2,068	1,995
Investments	1,578	1,849
Recurring | Level 2 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	27,530	31,485
Investments	66,398	61,112
Recurring | Level 2 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	14,164	16,156
Investments	2,739	2,871
Recurring | Level 2 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	7,740	10,047
Investments	188	177
Recurring | Level 2 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	1,557	981
Investments	274	300
Recurring | Level 2 | Other trading assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	15,378	20,346
Investments	3,756	4,877
Recurring | Level 2 | Non-marketable equity securities
Assets, Fair Value Disclosure [Abstract]
Investments	9	28
Recurring | Level 2 | Trading non-derivative assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	103,364	120,195
Recurring | Level 2 | Trading account derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	553,797	378,162
Recurring | Level 2 | Trading account derivatives | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	186,092	161,500
Recurring | Level 2 | Trading account derivatives | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	252,468	134,912
Recurring | Level 2 | Trading account derivatives | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	58,446	43,904
Recurring | Level 2 | Trading account derivatives | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	47,989	28,547
Recurring | Level 2 | Trading account derivatives | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	8,802	9,299
Recurring | Level 2 | Non-trading derivatives and other financial assets measured on a recurring basis
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	6,579	8,194
Recurring | Level 3
Assets, Fair Value Disclosure [Abstract]
Federal funds sold and securities borrowed and purchased under agreements to resell	141	231
Investments	2,233	2,227
Loans held at fair value	635	711
Mortgage servicing rights	647	404
Assets before netting	$ 16,777	$ 14,724
Total as a percentage of gross assets	1.20%	1.10%
Liabilities, Fair Value Disclosure [Abstract]
Interest-bearing deposits	$ 16	$ 183
Federal funds purchased and securities loaned and sold under agreements to repurchase, Gross	997	643
Securities sold, not yet purchased	103	65
Trading liabilities	105	65
Short-term borrowings	35	105
Long-term debt	31,710	25,509
Total liabilities, Gross	$ 42,225	$ 35,176
Total as a percentage of gross liabilities	4.50%	4.70%
Recurring | Level 3 | Trading account liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	$ 9,349	$ 8,670
Recurring | Level 3 | Trading account liabilities | Interest rate contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	3,787	2,172
Recurring | Level 3 | Trading account liabilities | Foreign exchange contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	581	726
Recurring | Level 3 | Trading account liabilities | Equity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	2,292	3,447
Recurring | Level 3 | Trading account liabilities | Commodity contracts
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	1,153	1,375
Recurring | Level 3 | Trading account liabilities | Credit derivatives
Liabilities, Fair Value Disclosure [Abstract]
Trading derivatives, liability	1,536	950
Recurring | Level 3 | Other financial liabilities measured on a recurring basis
Liabilities, Fair Value Disclosure [Abstract]
Other liabilities, gross	13	1
Recurring | Level 3 | Other trading liabilities
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	2	0
Recurring | Level 3 | Mortgage-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	930	681
Investments	65	145
Recurring | Level 3 | Mortgage securitizations - U.S. agency-sponsored
Assets, Fair Value Disclosure [Abstract]
Trading account assets	672	496
Investments	26	51
Recurring | Level 3 | Residential
Assets, Fair Value Disclosure [Abstract]
Trading account assets	142	104
Investments	39	94
Recurring | Level 3 | Commercial
Assets, Fair Value Disclosure [Abstract]
Trading account assets	116	81
Investments	0	0
Recurring | Level 3 | U.S. Treasury and federal agency securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	0	4
Investments	0	1
Recurring | Level 3 | State and municipal
Assets, Fair Value Disclosure [Abstract]
Trading account assets	22	37
Investments	575	772
Recurring | Level 3 | Foreign government
Assets, Fair Value Disclosure [Abstract]
Trading account assets	380	23
Investments	860	786
Recurring | Level 3 | Corporate
Assets, Fair Value Disclosure [Abstract]
Trading account assets	460	412
Investments	337	188
Recurring | Level 3 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	187	174
Investments	10	16
Recurring | Level 3 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Trading account assets	612	613
Investments	2	3
Recurring | Level 3 | Other trading assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	679	576
Investments	0	0
Recurring | Level 3 | Non-marketable equity securities
Assets, Fair Value Disclosure [Abstract]
Investments	384	316
Recurring | Level 3 | Trading non-derivative assets
Assets, Fair Value Disclosure [Abstract]
Trading account assets	3,270	2,520
Recurring | Level 3 | Trading account derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	9,801	8,558
Recurring | Level 3 | Trading account derivatives | Interest rate contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	3,761	3,898
Recurring | Level 3 | Trading account derivatives | Foreign exchange contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	858	637
Recurring | Level 3 | Trading account derivatives | Equity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	2,353	1,307
Recurring | Level 3 | Trading account derivatives | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	1,406	1,797
Recurring | Level 3 | Trading account derivatives | Credit derivatives
Assets, Fair Value Disclosure [Abstract]
Trading derivatives, asset, Gross	1,423	919
Recurring | Level 3 | Non-trading derivatives and other financial assets measured on a recurring basis
Assets, Fair Value Disclosure [Abstract]
Other assets, gross	$ 50	$ 73