ALLOWANCE FOR LOAN AND LEASE LOSSES - Schedule of Allowance for Loan and Lease Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	$ 1,747	$ 922	$ 178
Initial PCD ALLL	0	220	272
Day 2 Provision for Loan and Lease Losses	0	462	454
Provision (benefit) for loan and lease losses	469	703	97
Total provision for loan and lease losses	469	1,165	551
Charge-offs	(657)	(638)	(146)
Recoveries	117	78	67
Allowance for loan and lease losses, ending balance	1,676	1,747	922
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	1,126	789	80
Initial PCD ALLL	0	14	258
Day 2 Provision for Loan and Lease Losses	0	39	432
Provision (benefit) for loan and lease losses	298	651	101
Total provision for loan and lease losses	298	690	533
Charge-offs	(407)	(414)	(126)
Recoveries	46	47	44
Allowance for loan and lease losses, ending balance	1,063	1,126	789
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	166	133	98
Initial PCD ALLL	0	3	14
Day 2 Provision for Loan and Lease Losses	0	43	22
Provision (benefit) for loan and lease losses	8	2	(4)
Total provision for loan and lease losses	8	45	18
Charge-offs	(30)	(28)	(20)
Recoveries	14	13	23
Allowance for loan and lease losses, ending balance	158	166	133
SVB
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning balance	455	0	0
Initial PCD ALLL	0	203	0
Day 2 Provision for Loan and Lease Losses	0	380	0
Provision (benefit) for loan and lease losses	163	50	0
Total provision for loan and lease losses	163	430	0
Charge-offs	(220)	(196)	0
Recoveries	57	18	0
Allowance for loan and lease losses, ending balance	$ 455	$ 455	$ 0