LOANS AND LEASES - Loans Held For Sale (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	$ 676	$ 774
Other loans held for sale	103	208
Retail | Residential loans held for sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	614	666
Other loans held for sale	0	0
Commercial | Commercial loans held for sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	62	108
Other loans held for sale	$ 103	$ 208