LOANS AND LEASES - Schedule of Loans and Leases Delinquency Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 139,037	$ 132,333
Nonaccrual Loans	1,184	969
Loans and leases, net of allowance for loan and lease losses	140,221	133,302
Financing receivable, accrued interest reversed to nonaccrual status	14	10
Financing receivable, nonaccrual without allowance for credit loss	303	138
Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	751	944
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	516	552
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	126	269
90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	109	123
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	138,286	131,389
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	70,987	65,534
Nonaccrual Loans	812	698
Loans and leases, net of allowance for loan and lease losses	71,799	66,232
Commercial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	431	700
Commercial | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	245	362
Commercial | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	87	224
Commercial | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	99	114
Commercial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	70,556	64,834
Commercial | Commercial construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	5,100	3,916
Nonaccrual Loans	9	2
Loans and leases, net of allowance for loan and lease losses	5,109	3,918
Commercial | Commercial construction | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	23	52
Commercial | Commercial construction | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	21	43
Commercial | Commercial construction | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1	8
Commercial | Commercial construction | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1	1
Commercial | Commercial construction | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	5,077	3,864
Commercial | Owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	16,780	15,411
Nonaccrual Loans	62	60
Loans and leases, net of allowance for loan and lease losses	16,842	15,471
Commercial | Owner occupied commercial mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	41	29
Commercial | Owner occupied commercial mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	30	19
Commercial | Owner occupied commercial mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9	2
Commercial | Owner occupied commercial mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	8
Commercial | Owner occupied commercial mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	16,739	15,382
Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	15,769	14,584
Nonaccrual Loans	425	411
Loans and leases, net of allowance for loan and lease losses	16,194	14,995
Commercial | Non-owner occupied commercial mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	148	296
Commercial | Non-owner occupied commercial mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	43	97
Commercial | Non-owner occupied commercial mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27	160
Commercial | Non-owner occupied commercial mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	78	39
Commercial | Non-owner occupied commercial mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	15,621	14,288
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	31,355	29,600
Nonaccrual Loans	285	194
Loans and leases, net of allowance for loan and lease losses	31,640	29,794
Commercial | Commercial and industrial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	173	252
Commercial | Commercial and industrial | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	118	152
Commercial | Commercial and industrial | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	39	41
Commercial | Commercial and industrial | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	16	59
Commercial | Commercial and industrial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	31,182	29,348
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,983	2,023
Nonaccrual Loans	31	31
Loans and leases, net of allowance for loan and lease losses	2,014	2,054
Commercial | Leases | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	46	71
Commercial | Leases | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	33	51
Commercial | Leases | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	11	13
Commercial | Leases | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	7
Commercial | Leases | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,937	1,952
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	28,047	27,405
Nonaccrual Loans	181	154
Loans and leases, net of allowance for loan and lease losses	28,228	27,559
Consumer | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	256	194
Consumer | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	209	155
Consumer | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	37	32
Consumer | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10	7
Consumer | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27,791	27,211
Consumer | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	23,004	22,649
Nonaccrual Loans	148	127
Loans and leases, net of allowance for loan and lease losses	23,152	22,776
Consumer | Residential mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	206	154
Consumer | Residential mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	172	125
Consumer | Residential mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27	25
Consumer | Residential mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	7	4
Consumer | Residential mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	22,798	22,495
Consumer | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,543	2,144
Nonaccrual Loans	24	21
Loans and leases, net of allowance for loan and lease losses	2,567	2,165
Consumer | Revolving mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	24	15
Consumer | Revolving mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	20	13
Consumer | Revolving mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4	2
Consumer | Revolving mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Consumer | Revolving mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,519	2,129
Consumer | Consumer auto
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,515	1,437
Nonaccrual Loans	8	5
Loans and leases, net of allowance for loan and lease losses	1,523	1,442
Consumer | Consumer auto | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	15	11
Consumer | Consumer auto | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	12	9
Consumer | Consumer auto | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3	2
Consumer | Consumer auto | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Consumer | Consumer auto | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,500	1,426
Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	985	1,175
Nonaccrual Loans	1	1
Loans and leases, net of allowance for loan and lease losses	986	1,176
Consumer | Consumer other | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	11	14
Consumer | Consumer other | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	5	8
Consumer | Consumer other | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3	3
Consumer | Consumer other | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3	3
Consumer | Consumer other | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	974	1,161
SVB
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	40,003	39,394
Nonaccrual Loans	191	117
Loans and leases, net of allowance for loan and lease losses	40,194	39,511
SVB | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	64	50
SVB | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	62	35
SVB | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	13
SVB | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	2
SVB | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	39,939	39,344
SVB | Global fund banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27,904	25,553
Nonaccrual Loans	0	0
Loans and leases, net of allowance for loan and lease losses	27,904	25,553
SVB | Global fund banking | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Global fund banking | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Global fund banking | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Global fund banking | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Global fund banking | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27,904	25,553
SVB | Investor dependent - early stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	956	1,366
Nonaccrual Loans	41	37
Loans and leases, net of allowance for loan and lease losses	997	1,403
SVB | Investor dependent - early stage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9	19
SVB | Investor dependent - early stage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8	8
SVB | Investor dependent - early stage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1	9
SVB | Investor dependent - early stage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	2
SVB | Investor dependent - early stage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	947	1,347
SVB | Investor dependent - growth stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,150	2,860
Nonaccrual Loans	46	37
Loans and leases, net of allowance for loan and lease losses	2,196	2,897
SVB | Investor dependent - growth stage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	1
SVB | Investor dependent - growth stage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	0
SVB | Investor dependent - growth stage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	1
SVB | Investor dependent - growth stage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Investor dependent - growth stage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,148	2,859
SVB | Innovation C&I and cash flow dependent
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8,993	9,615
Nonaccrual Loans	104	43
Loans and leases, net of allowance for loan and lease losses	9,097	9,658
SVB | Innovation C&I and cash flow dependent | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	53	30
SVB | Innovation C&I and cash flow dependent | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	52	27
SVB | Innovation C&I and cash flow dependent | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1	3
SVB | Innovation C&I and cash flow dependent | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
SVB | Innovation C&I and cash flow dependent | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 8,940	$ 9,585