LOANS AND LEASES - Non-Performing Assets (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 102	$ 88
Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	102	88
Total non-performing loans	102	88
Other real estate owned	8	8
Total non-performing assets	$ 110	$ 96
Non-performing loans / total loans and leases	0.38%	0.35%
Non-performing assets + 90 days past due / total loans and leases + OREO	0.44%	0.41%
Past due	90 days	90 days