LOANS AND LEASES - Loans Held For Sale (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	$ 749	$ 774
Other loans held for sale	99	208
Residential loans held for sale | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	739	666
Other loans held for sale	0	0
Commercial loans held for sale | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at fair value	10	108
Other loans held for sale	$ 99	$ 208