BUSINESS OPERATING SEGMENTS - Schedule of Business Operating Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 6,012	$ 4,512	$ 4,586
Noninterest income	2,009	2,135	2,319
Total revenue	8,021	6,647	6,905
Noninterest expense	4,892	4,081	3,991
Profit (loss) before provision for credit losses	3,129	2,566	2,914
Provision (benefit) for credit losses	474	(411)	1,616
Income before income tax expense	2,655	2,977	1,298
Income tax expense	582	658	241
NET INCOME	2,073	2,319	1,057
Total average assets	215,061	185,106	176,442
Operating Segments
Segment Reporting Information [Line Items]
Noninterest income	2,009	2,135	2,319
Operating Segments | Consumer Banking
Segment Reporting Information [Line Items]
Net interest income	4,043	3,562	3,311
Noninterest income	1,063	1,223	1,655
Total revenue	5,106	4,785	4,966
Noninterest expense	3,391	2,987	2,964
Profit (loss) before provision for credit losses	1,715	1,798	2,002
Provision (benefit) for credit losses	226	185	288
Income before income tax expense	1,489	1,613	1,714
Income tax expense	381	410	429
NET INCOME	1,108	1,203	1,285
Total average assets	86,147	75,509	72,022
Operating Segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income	2,103	1,706	1,643
Noninterest income	845	809	595
Total revenue	2,948	2,515	2,238
Noninterest expense	1,223	973	860
Profit (loss) before provision for credit losses	1,725	1,542	1,378
Provision (benefit) for credit losses	46	156	398
Income before income tax expense	1,679	1,386	980
Income tax expense	375	300	206
NET INCOME	1,304	1,086	774
Total average assets	74,919	57,617	60,839
Other
Segment Reporting Information [Line Items]
Net interest income	(134)	(756)	(368)
Noninterest income	101	103	69
Total revenue	(33)	(653)	(299)
Noninterest expense	278	121	167
Profit (loss) before provision for credit losses	(311)	(774)	(466)
Provision (benefit) for credit losses	202	(752)	930
Income before income tax expense	(513)	(22)	(1,396)
Income tax expense	(174)	(52)	(394)
NET INCOME	(339)	30	(1,002)
Total average assets	$ 53,995	$ 51,980	$ 43,581