LOANS - Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Loans receivable
Loans, net of unearned income	$ 689,362	$ 657,221
Consumer
Loans receivable
Loans, net of unearned income	389,197	368,067
Consumer | In North America offices | 90+ days past due | Personal Banking and Wealth Management
Loans receivable
Loans, net of unearned income	29,200	31,500
Consumer | Outside U.S. | 90+ days past due | Personal Banking and Wealth Management
Loans receivable
Loans, net of unearned income	17,000
Consumer | Residential first mortgages
Loans receivable
Loans, net of unearned income	108,711	96,039
Consumer | Residential first mortgages | In offices outside North America
Loans receivable
Loans, net of unearned income	26,426	28,114
Consumer | Home equity loans
Loans receivable
Loans, net of unearned income	3,592	4,580
Consumer | Credit cards
Loans receivable
Loans, net of unearned income	164,110	150,098
Consumer | Credit cards | Outside U.S.
Loans receivable
Revolving loans converted to term loans	51	75
Consumer | Personal, small business and other
Loans receivable
Revolving loans converted to term loans	37	67
Loans, net of unearned income	$ 35,258	$ 36,812
Consumer | Personal, small business and other | In offices outside North America | Internal Investment Grade
Loans receivable
Percentage internal risk rating	92.00%	98.00%
Consumer | Less than or equal to 80%
Loans receivable
Loans, net of unearned income	$ 101,290	$ 90,741
Consumer | Less than or equal to 80% | Residential first mortgages
Loans receivable
2023	13,907	15,644
2022	17,736	19,104
2021	18,795	16,935
2020	16,094	8,789
2019	8,198	3,598
Prior	23,120	22,367
Loans, net of unearned income	97,850	86,437
Consumer | Less than or equal to 80% | Residential first mortgages | In offices outside North America
Loans receivable
2023	2,756	3,106
2022	3,229	4,144
2021	3,257	3,293
2020	2,286	3,048
2019	2,525	2,074
Prior	8,000	9,201
Loans, net of unearned income	$ 22,053	$ 24,866
Loan to value ratio	55.00%	51.00%
Consumer | Less than or equal to 80% | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	$ 2,964	$ 3,677
Consumer | Less than or equal to 80% | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	476	627
Consumer | Less than or equal to 80% | Home equity loans
Loans receivable
Loans, net of unearned income	3,440	4,304
Consumer | 80% but less than or equal to 100%
Loans receivable
Loans, net of unearned income	9,119	8,385
Consumer | 80% but less than or equal to 100% | Residential first mortgages
Loans receivable
2023	3,769	6,497
2022	3,900	1,227
2021	728	267
2020	306	140
2019	191	74
Prior	191	132
Loans, net of unearned income	9,085	8,337
Consumer | 80% but less than or equal to 100% | Residential first mortgages | In offices outside North America
Loans receivable
2023	1,007	975
2022	807	964
2021	754	502
2020	454	92
2019	84	48
Prior	84	36
Loans, net of unearned income	3,190	2,617
Consumer | 80% but less than or equal to 100% | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	29	36
Consumer | 80% but less than or equal to 100% | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	5	12
Consumer | 80% but less than or equal to 100% | Home equity loans
Loans receivable
Loans, net of unearned income	34	48
Consumer | Greater than 100%
Loans receivable
Loans, net of unearned income	207	263
Consumer | Greater than 100% | Residential first mortgages
Loans receivable
2023	3	40
2022	52	33
2021	33	1
2020	1	23
2019	26	9
Prior	23	74
Loans, net of unearned income	138	180
Consumer | Greater than 100% | Residential first mortgages | In offices outside North America
Loans receivable
2023	112	294
2022	439	273
2021	382	25
2020	62	1
2019	2	0
Prior	3	7
Loans, net of unearned income	1,000	600
Consumer | Greater than 100% | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	57	56
Consumer | Greater than 100% | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	12	27
Consumer | Greater than 100% | Home equity loans
Loans receivable
Loans, net of unearned income	69	83
Consumer | LTV not available
Loans receivable
Loans, net of unearned income	1,687	1,230
Consumer | LTV not available | Residential first mortgages
Loans receivable
Loans, net of unearned income	1,638	1,085
Consumer | LTV not available | Residential first mortgages | In offices outside North America
Loans receivable
Loans, net of unearned income	183	31
Consumer | LTV not available | Home equity loans
Loans receivable
Loans, net of unearned income	49	145
Consumer | Total
Loans receivable
Loans, net of unearned income	112,303	100,619
Consumer | Less than 680
Loans receivable
Loans, net of unearned income	39,065	34,306
Consumer | Less than 680 | Residential first mortgages
Loans receivable
2023	373	691
2022	655	639
2021	560	431
2020	376	321
2019	296	302
Prior	1,934	2,020
Loans, net of unearned income	4,194	4,404
Consumer | Less than 680 | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	425	552
Consumer | Less than 680 | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	79	62
Consumer | Less than 680 | Home equity term loans
Loans receivable
2023	0	0
2022	0	0
2021	0	1
2020	1	1
2019	1	1
Prior	78	103
Loans, net of unearned income	80	106
Consumer | Less than 680 | Home equity loans
Loans receivable
Loans, net of unearned income	584	720
Consumer | Less than 680 | Credit cards
Loans receivable
Loans, net of unearned income	32,500	27,901
Consumer | Less than 680 | Credit cards
Loans receivable
Revolving loans converted to term loans	1,154	766
Loans, net of unearned income	33,654	28,667
Consumer | Less than 680 | Credit cards | Canada
Loans receivable
Loans, net of unearned income	610	545
Consumer | Less than 680 | Personal, small business and other
Loans receivable
2023	138	247
2022	279	96
2021	69	15
2020	8	21
2019	7	10
Prior	132	126
Loans, net of unearned income	633	515
Consumer | Less than 680 | Personal, small business and other | Canada
Loans receivable
Loans, net of unearned income	877	940
Consumer | 680 to 760
Loans receivable
Loans, net of unearned income	95,566	89,490
Consumer | 680 to 760 | Residential first mortgages
Loans receivable
2023	5,396	7,530
2022	5,976	5,933
2021	5,430	4,621
2020	3,945	2,505
2019	2,214	1,072
Prior	6,406	6,551
Loans, net of unearned income	29,367	28,212
Consumer | 680 to 760 | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	1,174	1,536
Consumer | 680 to 760 | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	75	65
Consumer | 680 to 760 | Home equity term loans
Loans receivable
2023	0	0
2022	0	1
2021	0	2
2020	2	2
2019	1	2
Prior	121	144
Loans, net of unearned income	124	151
Consumer | 680 to 760 | Home equity loans
Loans receivable
Loans, net of unearned income	1,373	1,752
Consumer | 680 to 760 | Credit cards
Loans receivable
Loans, net of unearned income	63,334	58,213
Consumer | 680 to 760 | Credit cards
Loans receivable
Revolving loans converted to term loans	401	354
Loans, net of unearned income	63,735	58,567
Consumer | 680 to 760 | Personal, small business and other
Loans receivable
2023	438	546
2022	375	170
2021	88	20
2020	9	23
2019	6	10
Prior	175	190
Loans, net of unearned income	1,091	959
Consumer | Greater than 760
Loans receivable
Loans, net of unearned income	135,369	120,733
Consumer | Greater than 760 | Residential first mortgages
Loans receivable
2023	11,461	12,928
2022	13,965	12,672
2021	12,481	10,936
2020	10,881	5,445
2019	5,276	1,899
Prior	13,323	12,649
Loans, net of unearned income	67,387	56,529
Consumer | Greater than 760 | Home equity line of credit (pre-reset)
Loans receivable
Loans, net of unearned income	1,479	1,876
Consumer | Greater than 760 | Home equity line of credit (post-reset)
Loans receivable
Loans, net of unearned income	52	40
Consumer | Greater than 760 | Home equity term loans
Loans receivable
2023	0	0
2022	0	1
2021	1	2
2020	2	2
2019	1	1
Prior	95	111
Loans, net of unearned income	99	117
Consumer | Greater than 760 | Home equity loans
Loans receivable
Loans, net of unearned income	1,630	2,033
Consumer | Greater than 760 | Credit cards
Loans receivable
Loans, net of unearned income	64,712	60,896
Consumer | Greater than 760 | Credit cards
Loans receivable
Revolving loans converted to term loans	54	54
Loans, net of unearned income	64,766	60,950
Consumer | Greater than 760 | Personal, small business and other
Loans receivable
2023	851	800
2022	484	210
2021	106	30
2020	12	28
2019	7	9
Prior	126	144
Loans, net of unearned income	1,586	1,221
Consumer | Classifiably managed
Loans receivable
Loans, net of unearned income	29,209	31,478
Consumer | Classifiably managed | Residential first mortgages
Loans receivable
Loans, net of unearned income
Consumer | Classifiably managed | Home equity loans
Loans receivable
Loans, net of unearned income
Consumer | Classifiably managed | Credit cards
Loans receivable
Loans, net of unearned income
Consumer | Classifiably managed | Personal, small business and other
Loans receivable
Loans, net of unearned income	29,209	31,478
Consumer | FICO not available
Loans receivable
Loans, net of unearned income	12,462	11,522
Consumer | FICO not available | Residential first mortgages
Loans receivable
Loans, net of unearned income	7,763	6,894
Consumer | FICO not available | Home equity loans
Loans receivable
Loans, net of unearned income	5	75
Consumer | FICO not available | Credit cards
Loans receivable
Loans, net of unearned income	1,955	1,914
Consumer | FICO not available | Personal, small business and other
Loans receivable
Loans, net of unearned income	2,739	2,639
Consumer | Total loans
Loans receivable
Loans, net of unearned income	$ 311,671	$ 287,529