Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Summary of the Aging of Loans Broken out by Risk-based Segments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	$ 61,487	$ 45,181
Loans Past Due 90 Days or More Still Accruing Interest	3	0
30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	22	59
60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	6	7
Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	27	2
Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	55	68
Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	61,432	45,113
Global fund banking
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	34,120	25,543
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Global fund banking | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	28
Global fund banking | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Global fund banking | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Global fund banking | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	28
Global fund banking | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	34,120	25,515
Investor dependent
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	5,377	4,972
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Investor dependent | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3	17
Investor dependent | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	2
Investor dependent | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	1
Investor dependent | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3	20
Investor dependent | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	5,374	4,952
Investor dependent | Early stage
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,550	1,486
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Investor dependent | Early stage | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	6
Investor dependent | Early stage | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	2
Investor dependent | Early stage | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Investor dependent | Early stage | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	8
Investor dependent | Early stage | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,549	1,478
Investor dependent | Growth stage
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3,827	3,486
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Investor dependent | Growth stage | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	2	11
Investor dependent | Growth stage | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Investor dependent | Growth stage | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	1
Investor dependent | Growth stage | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	2	12
Investor dependent | Growth stage | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3,825	3,474
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,895	1,989
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Cash flow dependent - SLBO | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,895	1,989
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	5,916	5,136
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	7
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3	1
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	4	8
Cash flow dependent and innovation C&I (Commercial and Industrial) | Innovation C&I | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	5,912	5,128
Private bank
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	8,370	4,901
Loans Past Due 90 Days or More Still Accruing Interest	2	0
Private bank | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	4
Private bank | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	2	4
Private bank | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	8	0
Private bank | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	11	8
Private bank | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	8,359	4,893
CRE
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	2,753	0
Loans Past Due 90 Days or More Still Accruing Interest	0
CRE | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	14
CRE | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0
CRE | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0
CRE | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	14
CRE | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	2,739
Premium wine and other | Premium wine
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	980	1,053
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Premium wine and other | Premium wine | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	3
Premium wine and other | Premium wine | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Premium wine and other | Premium wine | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	17	1
Premium wine and other | Premium wine | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	17	4
Premium wine and other | Premium wine | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	963	1,049
Premium wine and other | Other
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	252	28
Loans Past Due 90 Days or More Still Accruing Interest	0	0
Premium wine and other | Other | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Premium wine and other | Other | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Premium wine and other | Other | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Premium wine and other | Other | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
Premium wine and other | Other | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	252	28
Other C&I
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,259	0
Loans Past Due 90 Days or More Still Accruing Interest	0
Other C&I | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	3
Other C&I | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1
Other C&I | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1
Other C&I | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	5
Other C&I | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1,254
PPP Loans
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	565	1,559
Loans Past Due 90 Days or More Still Accruing Interest	1	0
PPP Loans | 30 - 59   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
PPP Loans | 60 - 89   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	0	0
PPP Loans | Equal to or Greater Than 90   Days Past   Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	0
PPP Loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	1	0
PPP Loans | Current
Financing Receivable, Past Due [Line Items]
Loans, amortized cost	$ 564	$ 1,559