ALLOWANCE FOR CREDIT LOSSES - Allowance Roll-forward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]
ALLL balance, beginning of period	$ 2,331	$ 2,304	$ 2,244	$ 2,255
Loan and lease charge-offs	(137)	(129)	(381)	(402)
Recoveries of loans and leases previously charged-off	62	36	154	127
Provision for loan and lease losses	118	24	357	255
ALLL balance, end of period	2,374	2,235	2,374	2,235
AULC balance, beginning of period	184	119	202	145
Provision for unfunded lending commitments	4	82	(14)	56
AULC balance, end of period	188	201	188	201
ACL balance, end of period	2,562	2,436	2,562	2,436
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
ALLL balance, beginning of period	1,548	1,587	1,484	1,563
Loan and lease charge-offs	(80)	(74)	(210)	(243)
Recoveries of loans and leases previously charged-off	44	20	99	77
Provision for loan and lease losses	56	(35)	195	101
ALLL balance, end of period	1,568	1,498	1,568	1,498
AULC balance, beginning of period	124	64	144	66
Provision for unfunded lending commitments	1	76	(19)	74
AULC balance, end of period	125	140	125	140
ACL balance, end of period	1,693	1,638	1,693	1,638
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
ALLL balance, beginning of period	783	717	760	692
Loan and lease charge-offs	(57)	(55)	(171)	(159)
Recoveries of loans and leases previously charged-off	18	16	55	50
Provision for loan and lease losses	62	59	162	154
ALLL balance, end of period	806	737	806	737
AULC balance, beginning of period	60	55	58	79
Provision for unfunded lending commitments	3	6	5	(18)
AULC balance, end of period	63	61	63	61
ACL balance, end of period	$ 869	$ 798	$ 869	$ 798