PARENT COMPANY FINANCIAL STATEMENTS - Statements of Income of Parent Company Only (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Interest income	$ 1,973	$ 1,285	$ 1,005
Other income	12	19	26
Interest expense	656	165	98
Income tax benefit	(99)	(114)	(98)
Net income	485	439	405
Parent Company
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:	385	260	220
Interest income	16	16	13
Other income	1	0	0
Total Income	402	276	233
Interest expense	47	34	25
Other expenses	21	17	17
Total Expenses	68	51	42
Income Before Taxes and Equity in Undistributed Income of Subsidiaries	334	225	191
Income tax benefit	15	9	7
Income after income taxes	349	234	198
Equity in undistributed income of subsidiaries:	136	203	207
Net income	485	439	405
Parent Company | Bank
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:	382	254	215
Equity in undistributed income of subsidiaries:	130	200	207
Parent Company | Non-bank
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:	3	6	5
Equity in undistributed income of subsidiaries:	$ 6	$ 5	$ 0