LOANS - Consumer Loan Delinquency and Non-Accruals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) payment	Dec. 31, 2022 USD ($)
Loans receivable
Total loans	$ 689,362	$ 657,221
Loans held at fair value	7,594	5,360
Loans, net of unearned income	689,362	657,221
Reversal of accrued interest	$ 1,100	600
Open-ended consumer loans
Loans receivable
Minimum number of payments made consecutively for the loans to be re-aged | payment	3
Consumer
Loans receivable
Total loans	$ 389,197	368,067
Non-accrual loans for which there is no ACLL	159	140
Non-accrual loans for which there is an ACLL	1,156	1,177
Total non-accrual	1,315	1,317
90 days  past due and accruing	2,674	1,658
Loans held at fair value	313	237
Loans, net of unearned income	389,197	368,067
Unearned income related to consumer loans	802	712
Accrued interest receivable	1,000	1,000
Consumer | Classifiably managed
Loans receivable
Loans, net of unearned income	$ 29,209	31,478
Consumer | Minimum
Loans receivable
Minimum number of payments made consecutively for the loans to be re-aged | payment	1
Consumer | Maximum
Loans receivable
Minimum number of payments made consecutively for the loans to be re-aged | payment	3
Consumer | Current
Loans receivable
Total loans	$ 382,466	363,256
Consumer | Past due | Past due government guaranteed
Loans receivable
Total loans	239	286
Consumer | 30–89 days past due
Loans receivable
Total loans	3,259	2,372
Consumer | 90+ days past due
Loans receivable
Total loans	3,233	2,153
Consumer | In North America offices
Loans receivable
Total loans	313,158	289,014
Non-accrual loans for which there is no ACLL	159	140
Non-accrual loans for which there is an ACLL	569	608
Total non-accrual	728	748
90 days  past due and accruing	2,586	1,589
Consumer | In North America offices | Current
Loans receivable
Total loans	307,127	284,782
Consumer | In North America offices | Past due | Past due government guaranteed
Loans receivable
Total loans	239	286
Consumer | In North America offices | 30–89 days past due
Loans receivable
Total loans	2,895	2,058
Consumer | In North America offices | 90+ days past due
Loans receivable
Total loans	2,897	1,888
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 | In offices outside North America
Loans receivable
Total loans	76,039	79,053
Non-accrual loans for which there is no ACLL	0	0
Non-accrual loans for which there is an ACLL	587	569
Total non-accrual	587	569
90 days  past due and accruing	88	69
Consumer | In offices outside North America | Classifiably managed
Loans receivable
Total loans	17,007	17,762
Consumer | In offices outside North America | Current
Loans receivable
Total loans	75,339	78,474
Consumer | In offices outside North America | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | In offices outside North America | 30–89 days past due
Loans receivable
Total loans	364	314
Consumer | In offices outside North America | 90+ days past due
Loans receivable
Total loans	336	265
Consumer | In offices outside North America | 90+ days past due | Personal Banking and Wealth Management
Loans receivable
Total loans		17,800
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
Number of days past due, non-accrual status	90 days
Loans held at fair value	$ 313	237
Loans, net of unearned income	108,711	96,039
Consumer | Residential first mortgages | Classifiably managed
Loans receivable
Loans, net of unearned income
Consumer | Residential first mortgages | In North America offices
Loans receivable
Total loans	108,711	96,039
Non-accrual loans for which there is no ACLL	105	86
Non-accrual loans for which there is an ACLL	384	434
Total non-accrual	489	520
90 days  past due and accruing	120	163
Residential first mortgage loans in process of foreclosure	100	100
Consumer | Residential first mortgages | In North America offices | Current
Loans receivable
Total loans	107,720	95,023
Consumer | Residential first mortgages | In North America offices | Past due | Past due government guaranteed
Loans receivable
Total loans	235	279
Consumer | Residential first mortgages | In North America offices | 30–89 days past due
Loans receivable
Total loans	462	421
Consumer | Residential first mortgages | In North America offices | 30–89 days past due | Past due government guaranteed
Loans receivable
Total loans	100	100
Consumer | Residential first mortgages | In North America offices | 90+ days past due
Loans receivable
Total loans	294	316
Consumer | Residential first mortgages | In North America offices | 90+ days past due | Past due government guaranteed
Loans receivable
Total loans	100	200
Consumer | Residential first mortgages | In offices outside North America
Loans receivable
Total loans	26,426	28,114
Non-accrual loans for which there is no ACLL	0	0
Non-accrual loans for which there is an ACLL	243	305
Total non-accrual	243	305
90 days  past due and accruing	0	13
Residential first mortgage loans in process of foreclosure	0	0
Loans, net of unearned income	26,426	28,114
Consumer | Residential first mortgages | In offices outside North America | Classifiably managed
Loans receivable
Total loans	0	0
Consumer | Residential first mortgages | In offices outside North America | Global Wealth Management Business
Loans receivable
Total loans	19,900	19,800
Consumer | Residential first mortgages | In offices outside North America | Current
Loans receivable
Total loans	26,309	27,946
Consumer | Residential first mortgages | In offices outside North America | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | Residential first mortgages | In offices outside North America | 30–89 days past due
Loans receivable
Total loans	48	62
Consumer | Residential first mortgages | In offices outside North America | 90+ days past due
Loans receivable
Total loans	$ 69	106
Consumer | Home equity loans
Loans receivable
Number of days past due, non-accrual status	90 days
Loans, net of unearned income	$ 3,592	4,580
Consumer | Home equity loans | Classifiably managed
Loans receivable
Loans, net of unearned income
Consumer | Home equity loans | In North America offices
Loans receivable
Total loans	3,592	4,580
Non-accrual loans for which there is no ACLL	48	51
Non-accrual loans for which there is an ACLL	126	151
Total non-accrual	174	202
90 days  past due and accruing	0	0
Home equity loans in process of foreclosure	0	100
Consumer | Home equity loans | In North America offices | Current
Loans receivable
Total loans	3,471	4,407
Consumer | Home equity loans | In North America offices | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | Home equity loans | In North America offices | 30–89 days past due
Loans receivable
Total loans	36	38
Consumer | Home equity loans | In North America offices | 90+ days past due
Loans receivable
Total loans	$ 85	135
Consumer | Credit cards
Loans receivable
Number of days past due, non-accrual status	180 days
Loans, net of unearned income	$ 164,110	150,098
Consumer | Credit cards | Classifiably managed
Loans receivable
Loans, net of unearned income
Consumer | Credit cards | In North America offices
Loans receivable
Total loans	164,720	150,643
Non-accrual loans for which there is no ACLL	0	0
Non-accrual loans for which there is an ACLL	0	0
Total non-accrual	0	0
90 days  past due and accruing	2,461	1,415
Consumer | Credit cards | In North America offices | Current
Loans receivable
Total loans	159,966	147,717
Consumer | Credit cards | In North America offices | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | Credit cards | In North America offices | 30–89 days past due
Loans receivable
Total loans	2,293	1,511
Consumer | Credit cards | In North America offices | 90+ days past due
Loans receivable
Total loans	2,461	1,415
Consumer | Credit cards | In offices outside North America
Loans receivable
Total loans	14,233	12,955
Non-accrual loans for which there is no ACLL	0	0
Non-accrual loans for which there is an ACLL	211	127
Total non-accrual	211	127
90 days  past due and accruing	88	56
Consumer | Credit cards | In offices outside North America | Classifiably managed
Loans receivable
Total loans	0	0
Consumer | Credit cards | In offices outside North America | Current
Loans receivable
Total loans	13,797	12,659
Consumer | Credit cards | In offices outside North America | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | Credit cards | In offices outside North America | 30–89 days past due
Loans receivable
Total loans	209	147
Consumer | Credit cards | In offices outside North America | 90+ days past due
Loans receivable
Total loans	$ 227	149
Consumer | Personal, small business and other
Loans receivable
Number of days past due, non-accrual status	90 days
Loans, net of unearned income	$ 35,258	36,812
Consumer | Personal, small business and other | Classifiably managed
Loans receivable
Loans, net of unearned income	29,209	31,478
Consumer | Personal, small business and other | In North America offices
Loans receivable
Total loans	36,135	37,752
Non-accrual loans for which there is no ACLL	6	3
Non-accrual loans for which there is an ACLL	59	23
Total non-accrual	65	26
90 days  past due and accruing	5	11
Consumer | Personal, small business and other | In North America offices | Global Wealth Management Business
Loans receivable
Loans, net of unearned income	31,600	34,000
Consumer | Personal, small business and other | In North America offices | Current
Loans receivable
Total loans	35,970	37,635
Consumer | Personal, small business and other | In North America offices | Past due | Past due government guaranteed
Loans receivable
Total loans	4	7
Consumer | Personal, small business and other | In North America offices | 30–89 days past due
Loans receivable
Total loans	104	88
Consumer | Personal, small business and other | In North America offices | 90+ days past due
Loans receivable
Total loans	57	22
Consumer | Personal, small business and other | In offices outside North America
Loans receivable
Total loans	35,380	37,984
Non-accrual loans for which there is no ACLL	0	0
Non-accrual loans for which there is an ACLL	133	137
Total non-accrual	133	137
90 days  past due and accruing	0	0
Consumer | Personal, small business and other | In offices outside North America | Classifiably managed
Loans receivable
Total loans	$ 17,007	$ 17,762
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 | Personal, small business and other | In offices outside North America | Global Wealth Management Business | Internal Investment Grade
Loans receivable
Percentage internal risk rating	74.00%	94.00%
Consumer | Personal, small business and other | In offices outside North America | Current
Loans receivable
Total loans	$ 35,233	$ 37,869
Consumer | Personal, small business and other | In offices outside North America | Past due | Past due government guaranteed
Loans receivable
Total loans	0	0
Consumer | Personal, small business and other | In offices outside North America | 30–89 days past due
Loans receivable
Total loans	107	105
Consumer | Personal, small business and other | In offices outside North America | 90+ days past due
Loans receivable
Total loans	40	10
Consumer | Personal, small business and other | Outside U.S. | Global Wealth Management Business
Loans receivable
Loans, net of unearned income	$ 24,900	$ 26,600
Percentage internal risk rating		94.00%
Consumer | Mortgage loans other than federal housing administration-insured loans
Loans receivable
Number of days past due, non-accrual status	60 days
Consumer | Unsecured revolving loans
Loans receivable
Number of days past due, non-accrual status	180 days