LOANS AND LEASES - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable		$ 875	$ 820
Net loans and leases	[1]	143,861	154,679
Interest income on direct financing and sales-type leases		46	46	$ 49
Retail | Residential mortgages | Pledged as collateral for FHLB borrowing capacity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net loans and leases		36,000	38,400
Retail and Commercial | Auto, commercial and commercial real estate loans | Notes Payable, Other Payables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net loans and leases		$ 31,900	$ 34,800
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Term of contract		3 years
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Term of contract		10 years

[1] Includes amounts in consolidated VIEs. See Note 11 for additional information.