COMMITMENTS AND CONTINGENCIES - Schedule of Outstanding Off-balance sheet Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other Commitments [Line Items]
Commitment amount	$ 96,608	$ 96,295
Commitments to extend credit
Other Commitments [Line Items]
Commitment amount	94,436	94,201
Letters of credit
Other Commitments [Line Items]
Commitment amount	2,055	1,977
Loans sold with recourse
Other Commitments [Line Items]
Commitment amount	99	96
Marketing rights
Other Commitments [Line Items]
Commitment amount	17	18
Risk participation agreements
Other Commitments [Line Items]
Commitment amount	$ 1	$ 3