Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Credit Quality Indicators, Broken out by Risk-Based Segments and Vintage Year (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	$ 8,189	$ 9,153
Year Two	6,755	4,008
Year Three	3,528	1,863
Year Four	1,639	934
Year Five	1,217	530
Prior	2,651	600
Revolving Loans	37,456	28,038
Revolving Loans Converted to Term Loans	81	55
Unallocated	(29)
Loans, amortized cost	61,487	45,181
Global fund banking
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	470	440
Year Two	111	48
Year Three	40	69
Year Four	54	23
Year Five	12	2
Prior	6	6
Revolving Loans	33,426	24,947
Revolving Loans Converted to Term Loans	1	8
Unallocated	0
Loans, amortized cost	34,120	25,543
Global fund banking \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	0	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	0	0
Global fund banking \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	470	440
Year Two	111	48
Year Three	40	69
Year Four	54	23
Year Five	12	2
Prior	6	6
Revolving Loans	33,423	24,947
Revolving Loans Converted to Term Loans	0	2
Unallocated	0
Loans, amortized cost	34,116	25,537
Global fund banking \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	3	0
Revolving Loans Converted to Term Loans	1	6
Unallocated	0
Loans, amortized cost	4	6
Investor dependent
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	2,320	2,544
Year Two	1,703	1,254
Year Three	629	528
Year Four	161	116
Year Five	32	10
Prior	3	17
Revolving Loans	524	494
Revolving Loans Converted to Term Loans	5	9
Unallocated	0
Loans, amortized cost	5,377	4,972
Investor dependent \| Early stage
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	631	716
Year Two	485	452
Year Three	208	152
Year Four	41	43
Year Five	9	5
Prior	1	1
Revolving Loans	175	116
Revolving Loans Converted to Term Loans	0	1
Unallocated	0
Loans, amortized cost	1,550	1,486
Investor dependent \| Early stage \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	2
Year Two	0	9
Year Three	3	5
Year Four	1	1
Year Five	0	0
Prior	0	0
Revolving Loans	0	1
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	4	18
Investor dependent \| Early stage \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	605	667
Year Two	386	370
Year Three	174	121
Year Four	35	32
Year Five	8	1
Prior	1	1
Revolving Loans	149	96
Revolving Loans Converted to Term Loans	0	1
Unallocated	0
Loans, amortized cost	1,358	1,289
Investor dependent \| Early stage \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	26	47
Year Two	99	73
Year Three	31	26
Year Four	5	10
Year Five	1	4
Prior	0	0
Revolving Loans	26	19
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	188	179
Investor dependent \| Growth stage
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	1,689	1,828
Year Two	1,218	802
Year Three	421	376
Year Four	120	73
Year Five	23	5
Prior	2	16
Revolving Loans	349	378
Revolving Loans Converted to Term Loans	5	8
Unallocated	0
Loans, amortized cost	3,827	3,486
Investor dependent \| Growth stage \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	17
Year Two	14	3
Year Three	1	4
Year Four	3	3
Year Five	0	0
Prior	0	0
Revolving Loans	8	6
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	26	33
Investor dependent \| Growth stage \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	1,609	1,746
Year Two	1,120	696
Year Three	369	316
Year Four	113	61
Year Five	22	5
Prior	2	9
Revolving Loans	316	325
Revolving Loans Converted to Term Loans	5	8
Unallocated	0
Loans, amortized cost	3,556	3,166
Investor dependent \| Growth stage \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	80	65
Year Two	84	103
Year Three	51	56
Year Four	4	9
Year Five	1	0
Prior	0	7
Revolving Loans	25	47
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	245	287
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Cash flow dependent - SLBO
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	782	791
Year Two	503	534
Year Three	310	329
Year Four	143	196
Year Five	102	50
Prior	13	0
Revolving Loans	42	89
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	1,895	1,989
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Cash flow dependent - SLBO \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	12
Year Three	12	16
Year Four	10	7
Year Five	7	0
Prior	0	0
Revolving Loans	5	5
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	34	40
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Cash flow dependent - SLBO \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	780	791
Year Two	489	452
Year Three	280	274
Year Four	94	167
Year Five	85	37
Prior	0	0
Revolving Loans	34	75
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	1,762	1,796
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Cash flow dependent - SLBO \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	2	0
Year Two	14	70
Year Three	18	39
Year Four	39	22
Year Five	10	13
Prior	13	0
Revolving Loans	3	9
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	99	153
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Innovation C&I
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	1,461	1,793
Year Two	1,410	775
Year Three	407	417
Year Four	277	156
Year Five	131	39
Prior	3	0
Revolving Loans	2,227	1,955
Revolving Loans Converted to Term Loans	0	1
Unallocated	0
Loans, amortized cost	5,916	5,136
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Innovation C&I \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	5
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	0	1
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	0	6
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Innovation C&I \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	1,426	1,718
Year Two	1,298	703
Year Three	334	378
Year Four	260	152
Year Five	131	39
Prior	3	0
Revolving Loans	1,983	1,791
Revolving Loans Converted to Term Loans	0	1
Unallocated	0
Loans, amortized cost	5,435	4,782
Cash flow dependent and innovation C&I (Commercial and Industrial) \| Innovation C&I \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	35	75
Year Two	112	72
Year Three	73	34
Year Four	17	4
Year Five	0	0
Prior	0	0
Revolving Loans	244	163
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	481	348
Private bank
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	2,163	1,881
Year Two	2,159	1,163
Year Three	1,265	402
Year Four	569	354
Year Five	500	300
Prior	1,075	416
Revolving Loans	628	384
Revolving Loans Converted to Term Loans	11	1
Unallocated	0
Loans, amortized cost	8,370	4,901
Private bank \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	3
Year Four	1	0
Year Five	0	0
Prior	9	2
Revolving Loans	0	1
Revolving Loans Converted to Term Loans	1	0
Unallocated	0
Loans, amortized cost	11	6
Private bank \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	2,163	1,878
Year Two	2,159	1,153
Year Three	1,259	394
Year Four	566	353
Year Five	496	295
Prior	1,053	406
Revolving Loans	625	382
Revolving Loans Converted to Term Loans	10	1
Unallocated	0
Loans, amortized cost	8,331	4,862
Private bank \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	3
Year Two	0	10
Year Three	6	5
Year Four	2	1
Year Five	4	5
Prior	13	8
Revolving Loans	3	1
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	28	33
CRE
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	259
Year Two	278
Year Three	473
Year Four	224
Year Five	313
Prior	1,052
Revolving Loans	139
Revolving Loans Converted to Term Loans	15
Unallocated	0
Loans, amortized cost	2,753	0
CRE \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0
Year Two	0
Year Three	5
Year Four	14
Year Five	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Unallocated	0
Loans, amortized cost	19
CRE \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	256
Year Two	249
Year Three	359
Year Four	160
Year Five	263
Prior	927
Revolving Loans	120
Revolving Loans Converted to Term Loans	15
Unallocated	0
Loans, amortized cost	2,349
CRE \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	3
Year Two	29
Year Three	109
Year Four	50
Year Five	50
Prior	125
Revolving Loans	19
Revolving Loans Converted to Term Loans	0
Unallocated	0
Loans, amortized cost	385
Premium wine and other \| Premium wine
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	131	145
Year Two	143	218
Year Three	200	107
Year Four	84	89
Year Five	76	129
Prior	186	160
Revolving Loans	126	169
Revolving Loans Converted to Term Loans	34	36
Unallocated	0
Loans, amortized cost	980	1,053
Premium wine and other \| Premium wine \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	7	0
Year Four	0	0
Year Five	10	1
Prior	0	0
Revolving Loans	0	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	17	1
Premium wine and other \| Premium wine \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	129	127
Year Two	131	194
Year Three	182	71
Year Four	68	79
Year Five	66	115
Prior	148	154
Revolving Loans	114	135
Revolving Loans Converted to Term Loans	34	36
Unallocated	0
Loans, amortized cost	872	911
Premium wine and other \| Premium wine \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	2	18
Year Two	12	24
Year Three	11	36
Year Four	16	10
Year Five	0	13
Prior	38	6
Revolving Loans	12	34
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	91	141
Premium wine and other \| Other
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	25	0
Year Two	114	16
Year Three	98	11
Year Four	24	0
Year Five	16	0
Prior	0	1
Revolving Loans	4	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	(29)
Loans, amortized cost	252	28
Premium wine and other \| Other \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	0	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	0	0
Premium wine and other \| Other \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	25	0
Year Two	114	16
Year Three	97	11
Year Four	21	0
Year Five	13	0
Prior	0	1
Revolving Loans	4	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	(29)
Loans, amortized cost	245	28
Premium wine and other \| Other \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0	0
Year Two	0	0
Year Three	1	0
Year Four	3	0
Year Five	3	0
Prior	0	0
Revolving Loans	0	0
Revolving Loans Converted to Term Loans	0	0
Unallocated	0
Loans, amortized cost	7	0
Other C&I
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	164
Year Two	183
Year Three	106
Year Four	103
Year Five	35
Prior	313
Revolving Loans	340
Revolving Loans Converted to Term Loans	15
Unallocated	0
Loans, amortized cost	1,259	0
Other C&I \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	0
Year Two	0
Year Three	0
Year Four	1
Year Five	0
Prior	1
Revolving Loans	1
Revolving Loans Converted to Term Loans	0
Unallocated	0
Loans, amortized cost	3
Other C&I \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	159
Year Two	179
Year Three	96
Year Four	93
Year Five	33
Prior	310
Revolving Loans	324
Revolving Loans Converted to Term Loans	10
Unallocated	0
Loans, amortized cost	1,204
Other C&I \| Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Year One	5
Year Two	4
Year Three	10
Year Four	9
Year Five	2
Prior	2
Revolving Loans	15

Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Credit Quality Indicators, Broken out by Risk-Based Segments and Vintage Year (Details) - USD ($)
$ in Millions