ALLOWANCE FOR CREDIT LOSSES, NONACCRUAL LOANS AND LEASES, AND CONCENTRATIONS OF CREDIT RISK - Troubled Debt Restructurings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR's that defaulted within 12 months of modification date	$ 242	$ 118	$ 100
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR's that defaulted within 12 months of modification date	0	23	54
Retail | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR's that defaulted within 12 months of modification date	242	95	46
Retail | Loans Insured or Guaranteed by US Government Authorities
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR's that defaulted within 12 months of modification date	$ 187	$ 61	$ 16