CREDIT QUALITY AND THE ALLOWANCE FOR CREDIT LOSSES - Summary of Changes in Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses, beginning of period	$ 2,061	$ 2,098	$ 1,983
Charge-offs	(817)	(923)	(757)
Recoveries	133	177	148
Net charge-offs	(684)	(746)	(609)
Provision expense (benefit) for loans and leases	566	709	724
Allowance for loan and lease losses, end of period	1,943	2,061	2,098
Unfunded lending commitments [Roll Forward]
Allowance for unfunded lending commitments, beginning of period	198	220	257
Provision expense (benefit) for unfunded lending commitments	42	(22)	(37)
Allowance for unfunded lending commitments, end of period	240	198	220
Total allowance for credit losses, end of period	2,183	2,259	2,318
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses, beginning of period	1,140	1,250	1,060
Charge-offs	(351)	(419)	(285)
Recoveries	18	43	18
Net charge-offs	(333)	(376)	(267)
Provision expense (benefit) for loans and leases	251	266	457
Allowance for loan and lease losses, end of period	1,058	1,140	1,250
Unfunded lending commitments [Roll Forward]
Allowance for unfunded lending commitments, beginning of period	155	175	207
Provision expense (benefit) for unfunded lending commitments	39	(20)	(32)
Allowance for unfunded lending commitments, end of period	194	155	175
Total allowance for credit losses, end of period	1,252	1,295	1,425
Retail
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses, beginning of period	921	848	923
Charge-offs	(466)	(504)	(472)
Recoveries	115	134	130
Net charge-offs	(351)	(370)	(342)
Provision expense (benefit) for loans and leases	315	443	267
Allowance for loan and lease losses, end of period	885	921	848
Unfunded lending commitments [Roll Forward]
Allowance for unfunded lending commitments, beginning of period	43	45	50
Provision expense (benefit) for unfunded lending commitments	3	(2)	(5)
Allowance for unfunded lending commitments, end of period	46	43	45
Total allowance for credit losses, end of period	$ 931	$ 964	$ 893