LOANS AND LEASES - Schedule of Amortized Cost of Loans (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net unamortized discount	$ 1,524	$ 1,598
Non-PCD
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred fees, including unamortized costs and unearned fees on non-PCD loans	(85)	(91)
Total net unamortized discount	1,449	1,504
PCD
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net unamortized discount	$ 75	$ 94