NONINTEREST INCOME - Components of Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,533	$ 1,266	$ 1,299
Total noninterest income	2,176	1,983	2,009
Bank-owned life insurance	108	93	88
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources	643	717	710
Total noninterest income	2,176	1,983	2,009
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	25	1	4
Total revenue from other sources	112	131	97
Total noninterest income	137	132	101
Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	869	783	769
Consumer Banking | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources	262	284	294
Total noninterest income	1,131	1,067	1,063
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	639	482	526
Commercial Banking | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources	269	302	319
Total noninterest income	908	784	845
Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Non-Core | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenue from other sources	0	0	0
Total noninterest income	0	0	0
Service charges and fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	417	409	418
Service charges and fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	3
Service charges and fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	288	277	291
Service charges and fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	128	131	124
Service charges and fees | Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Card fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	362	291	271
Card fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	0	0
Card fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	284	244	228
Card fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	54	47	43
Card fees | Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Capital markets fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	445	293	341
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	445	293	341
Capital markets fees | Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Wealth fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	294	259	250
Wealth fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Wealth fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	294	259	249
Wealth fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	1
Wealth fees | Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Other banking fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15	14	19
Other banking fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	1
Other banking fees | Consumer Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	3	1
Other banking fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	11	17
Other banking fees | Non-Core
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 0