Loans and Leases - Schedule of Loans and Leases Delinquency Status (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 133,202	$ 70,781	$ 69,790
Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,166	864
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	369	480
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	231	214
90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	566	170
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	132,036	69,917
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	58,050	53,455
Commercial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	798	685
Commercial | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	197	387
Commercial | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	129	192
Commercial | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	472	106
Commercial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	57,252	52,770
Commercial | Commercial construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3,382	2,804
Commercial | Commercial construction | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	40	51
Commercial | Commercial construction | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	17	50
Commercial | Commercial construction | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	11	0
Commercial | Commercial construction | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	12	1
Commercial | Commercial construction | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3,342	2,753
Commercial | Owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	15,230	14,473
Commercial | Owner occupied commercial mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	77	59
Commercial | Owner occupied commercial mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	29	29
Commercial | Owner occupied commercial mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4	5
Commercial | Owner occupied commercial mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	44	25
Commercial | Owner occupied commercial mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	15,153	14,414
Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10,941	9,902
Commercial | Non-owner occupied commercial mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	375	231
Commercial | Non-owner occupied commercial mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1	76
Commercial | Non-owner occupied commercial mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	45	144
Commercial | Non-owner occupied commercial mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	329	11
Commercial | Non-owner occupied commercial mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10,566	9,671
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	26,389	24,105
Commercial | Commercial and industrial | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	235	252
Commercial | Commercial and industrial | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	107	173
Commercial | Commercial and industrial | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	53	26
Commercial | Commercial and industrial | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	75	53
Commercial | Commercial and industrial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	26,154	23,853
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,108	2,171
Commercial | Leases | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	71	92
Commercial | Leases | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	43	59
Commercial | Leases | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	16	17
Commercial | Leases | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	12	16
Commercial | Leases | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,037	2,079
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	18,288	17,326
Consumer | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	215	179
Consumer | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	120	93
Consumer | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	29	22
Consumer | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	66	64
Consumer | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	18,073	17,147
Consumer | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	14,287	13,309
Consumer | Residential mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	169	141
Consumer | Residential mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	95	73
Consumer | Residential mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	22	16
Consumer | Residential mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	52	52
Consumer | Residential mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	14,118	13,168
Consumer | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,909	1,951
Consumer | Revolving mortgage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	25	20
Consumer | Revolving mortgage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	13	9
Consumer | Revolving mortgage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3	3
Consumer | Revolving mortgage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9	8
Consumer | Revolving mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,884	1,931
Consumer | Consumer auto
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,411	1,414
Consumer | Consumer auto | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	12	9
Consumer | Consumer auto | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8	7
Consumer | Consumer auto | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	1
Consumer | Consumer auto | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	1
Consumer | Consumer auto | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,399	1,405
Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	681	652
Consumer | Consumer other | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9	9
Consumer | Consumer other | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4	4
Consumer | Consumer other | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2	2
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	672	643
SVB
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	56,864	0
SVB | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	153
SVB | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	52
SVB | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	73
SVB | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	28
SVB | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	56,711
SVB | Global fund banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27,516	0
SVB | Global fund banking | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | Global fund banking | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | Global fund banking | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | Global fund banking | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | Global fund banking | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	27,516
SVB | Investor dependent - early stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,718	0
SVB | Investor dependent - early stage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	18
SVB | Investor dependent - early stage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4
SVB | Investor dependent - early stage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	7
SVB | Investor dependent - early stage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	7
SVB | Investor dependent - early stage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,700
SVB | Investor dependent - growth stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3,948	0
SVB | Investor dependent - growth stage | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	23
SVB | Investor dependent - growth stage | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	5
SVB | Investor dependent - growth stage | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	17
SVB | Investor dependent - growth stage | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1
SVB | Investor dependent - growth stage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	3,925
SVB | Innovation C&I and cash flow dependent
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8,724	0
SVB | Innovation C&I and cash flow dependent | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	58
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	19
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	37
SVB | Innovation C&I and cash flow dependent | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2
SVB | Innovation C&I and cash flow dependent | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8,666
SVB | Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9,648	0
SVB | Private Bank | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	32
SVB | Private Bank | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	8
SVB | Private Bank | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10
SVB | Private Bank | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	14
SVB | Private Bank | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9,616
SVB | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,629	0
SVB | CRE | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10
SVB | CRE | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10
SVB | CRE | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | CRE | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
SVB | CRE | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,619
SVB | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,681	$ 0
SVB | Other | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	12
SVB | Other | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	6
SVB | Other | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2
SVB | Other | 90 Days or Greater
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4
SVB | Other | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 2,669