LOANS - Corporate Loan Delinquency (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	$ 645,960	$ 667,767
Loans held at fair value	3,879	6,082
Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	400	500
Corporate
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	1,785	1,895
Total non-accrual	1,485	1,553
Loans, net of unearned income	288,377	291,233
Loans held at fair value	3,638	6,070
Corporate | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	1,289	1,311
Total non-accrual	1,085	1,263
Loans, net of unearned income	151,610	147,004
Corporate | Financial institutions
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	287	486
Total non-accrual	178	2
Loans, net of unearned income	66,904	71,767
Corporate | Mortgage and real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	37	2
Total non-accrual	110	136
Loans, net of unearned income	21,720	20,291
Corporate | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	0	0
Total non-accrual	10	14
Loans, net of unearned income	431	455
Corporate | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	172	96
Total non-accrual	102	138
Loans, net of unearned income	44,074	45,646
Corporate | 30 to 89 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	813	1,470
Corporate | 30 to 89 days past due | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	598	1,072
Corporate | 30 to 89 days past due | Financial institutions
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	147	320
Corporate | 30 to 89 days past due | Mortgage and real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	22	1
Corporate | 30 to 89 days past due | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	0	0
Corporate | 30 to 89 days past due | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	46	77
Corporate | Equal to and greater than 90 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	972	425
Corporate | Equal to and greater than 90 days past due and accruing | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	691	239
Corporate | Equal to and greater than 90 days past due and accruing | Financial institutions
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	140	166
Corporate | Equal to and greater than 90 days past due and accruing | Mortgage and real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	15	1
Corporate | Equal to and greater than 90 days past due and accruing | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	0	0
Corporate | Equal to and greater than 90 days past due and accruing | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Past due and accruing	126	19
Corporate | Current
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	281,469	281,715
Corporate | Current | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	149,236	144,430
Corporate | Current | Financial institutions
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	66,439	71,279
Corporate | Current | Mortgage and real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	21,573	20,153
Corporate | Current | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	421	441
Corporate | Current | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	$ 43,800	$ 45,412