LOANS - Loan-to-Value Ratios Consumer Loans (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	$ 651,995	$ 657,221
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	363,696	368,067
Consumer | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	77,307	79,053
Consumer | Less than or equal to 80% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	90,499	90,741
Consumer | Greater than 80% but less than or equal to 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	11,118	8,385
Consumer | Greater than 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	307	263
Consumer | LTV not available | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	1,110	1,230
Consumer | Total | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	103,034	100,619
Consumer | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	98,790	96,039
Consumer | Residential mortgages | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	98,790	96,039
Consumer | Residential mortgages | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	26,913	28,114
Consumer | Residential mortgages | Less than or equal to 80% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	2,464	15,644
One year prior to current fiscal year	14,533	19,104
Two years prior to current fiscal year	18,590	16,935
Three years prior to current fiscal year	16,678	8,789
Four years prior to current fiscal year	8,532	3,598
Prior	25,655	22,367
Loans, net of unearned income	86,452	86,437
Consumer | Residential mortgages | Less than or equal to 80% | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	966	3,106
One year prior to current fiscal year	3,165	4,144
Two years prior to current fiscal year	3,816	3,293
Three years prior to current fiscal year	2,927	3,048
Four years prior to current fiscal year	2,841	2,074
Prior	9,668	9,201
Loans, net of unearned income	$ 23,383	$ 24,866
Loan to value ratio	52.00%	51.00%
Consumer | Residential mortgages | Greater than 80% but less than or equal to 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 985	$ 6,497
One year prior to current fiscal year	7,710	1,227
Two years prior to current fiscal year	1,556	267
Three years prior to current fiscal year	336	140
Four years prior to current fiscal year	220	74
Prior	261	132
Loans, net of unearned income	11,068	8,337
Consumer | Residential mortgages | Greater than 80% but less than or equal to 100% | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	399	975
One year prior to current fiscal year	1,018	964
Two years prior to current fiscal year	966	502
Three years prior to current fiscal year	475	92
Four years prior to current fiscal year	78	48
Prior	68	36
Loans, net of unearned income	3,004	2,617
Consumer | Residential mortgages | Greater than 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	40
One year prior to current fiscal year	148	33
Two years prior to current fiscal year	33	1
Three years prior to current fiscal year	1	23
Four years prior to current fiscal year	26	9
Prior	24	74
Loans, net of unearned income	232	180
Consumer | Residential mortgages | Greater than 100% | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	294
One year prior to current fiscal year	190	273
Two years prior to current fiscal year	197	25
Three years prior to current fiscal year	0	1
Four years prior to current fiscal year	1	0
Prior	8	7
Loans, net of unearned income	396	600
Consumer | Residential mortgages | LTV not available | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	1,038	1,085
Consumer | Residential mortgages | LTV not available | In offices outside North America
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	130	31
Consumer | Home equity loans (pre-reset) | Less than or equal to 80% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	3,559	3,677
Consumer | Home equity loans (pre-reset) | Greater than 80% but less than or equal to 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	41	36
Consumer | Home equity loans (pre-reset) | Greater than 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	61	56
Consumer | Home equity loans (post-reset) | Less than or equal to 80% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	488	627
Consumer | Home equity loans (post-reset) | Greater than 80% but less than or equal to 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	9	12
Consumer | Home equity loans (post-reset) | Greater than 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	14	27
Consumer | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	4,244	4,580
Consumer | Home equity loans | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	4,244	4,580
Consumer | Home equity loans | Less than or equal to 80% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	4,047	4,304
Consumer | Home equity loans | Greater than 80% but less than or equal to 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	50	48
Consumer | Home equity loans | Greater than 100% | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	75	83
Consumer | Home equity loans | LTV not available | UNITED STATES
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	$ 72	$ 145