NONINTEREST INCOME - Components of Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,299	$ 1,325	$ 1,080
Total noninterest income	2,009	2,135	2,319
Bank-owned life insurance	88	67	57
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources(1)	710	810	1,239
Total noninterest income	2,009	2,135	2,319
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	0	0
Total revenue from other sources(1)	97	103	69
Total noninterest income	101	103	69
Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	769	757	690
Consumer Banking | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources(1)	294	466	965
Total noninterest income	1,063	1,223	1,655
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	526	568	390
Commercial Banking | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources(1)	319	241	205
Total noninterest income	845	809	595
Service charges and fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	418	407	401
Service charges and fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	0	0
Service charges and fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	291	302	301
Service charges and fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	124	105	100
Card fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	271	248	216
Card fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Card fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	228	216	185
Card fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	43	32	31
Capital markets fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	341	419	249
Capital markets fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Capital markets fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Capital markets fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	341	419	249
Trust and investment services fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	250	239	203
Trust and investment services fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Trust and investment services fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	249	239	203
Trust and investment services fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0	0
Other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	19	12	11
Other banking fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0	0
Other banking fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0	1
Other banking fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 17	$ 12	$ 10