Loans - Credit Risk Profile of Commercial Loans (Detail) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Total	[1]	$ 55,864	$ 62,088
Commercial loans:
Financing Receivable, Credit Quality Indicator [Line Items]
2021		3,735	2,510
2020		2,458	5,322
2019		3,778	3,469
2018		2,590	2,039
2017		1,184	639
Prior		11,747	11,882
Revolving Loans		14,071	15,396
Revolving Loans Converted to Term Loans		233	342
Total		39,796	41,599
Commercial loans: | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2021		969	545
2020		653	3,775
2019		2,516	2,799
2018		2,116	1,368
2017		593	264
Prior		1,325	1,614
Revolving Loans		46	79
Revolving Loans Converted to Term Loans		16	20
Total		8,234	10,464
Commercial loans: | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		1,630	1,080
2020		713	621
2019		608	265
2018		220	335
2017		238	152
Prior		4,757	3,488
Revolving Loans		5,575	7,216
Revolving Loans Converted to Term Loans		217	322
Total		13,958	13,479
Commercial loans: | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		547	507
2020		540	495
2019		203	190
2018		80	231
2017		243	104
Prior		4,620	6,150
Revolving Loans		4,876	5,842
Revolving Loans Converted to Term Loans		0	0
Total		11,109	13,519
Commercial loans: | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021		589	378
2020		552	431
2019		451	215
2018		174	105
2017		110	119
Prior		1,045	630
Revolving Loans		3,574	2,259
Revolving Loans Converted to Term Loans		0	0
Total		6,495	4,137
Commercial loans: | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2021		1,532	1,517
2020		1,596	1,910
2019		1,073	1,017
2018		1,062	688
2017		404	348
Prior		7,223	7,269
Revolving Loans		10,277	8,718
Revolving Loans Converted to Term Loans		55	47
Total		23,222	21,514
Commercial loans: | Investment grade | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2021		1	339
2020		361	1,123
2019		491	817
2018		772	318
2017		57	179
Prior		248	640
Revolving Loans		12	6
Revolving Loans Converted to Term Loans		0	0
Total		1,942	3,422
Commercial loans: | Investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		881	342
2020		254	147
2019		240	37
2018		52	34
2017		43	23
Prior		2,122	1,486
Revolving Loans		2,498	2,499
Revolving Loans Converted to Term Loans		55	47
Total		6,145	4,615
Commercial loans: | Investment grade | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		530	464
2020		539	477
2019		189	46
2018		64	231
2017		235	30
Prior		3,910	4,618
Revolving Loans		4,240	4,281
Revolving Loans Converted to Term Loans		0	0
Total		9,707	10,147
Commercial loans: | Investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021		120	372
2020		442	163
2019		153	117
2018		174	105
2017		69	116
Prior		943	525
Revolving Loans		3,527	1,932
Revolving Loans Converted to Term Loans		0	0
Total		5,428	3,330
Commercial loans: | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2021		2,203	993
2020		862	3,412
2019		2,705	2,452
2018		1,528	1,351
2017		780	291
Prior		4,524	4,613
Revolving Loans		3,794	6,678
Revolving Loans Converted to Term Loans		178	295
Total		16,574	20,085
Commercial loans: | Non-investment grade | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2021		968	206
2020		292	2,652
2019		2,025	1,982
2018		1,344	1,050
2017		536	85
Prior		1,077	974
Revolving Loans		34	73
Revolving Loans Converted to Term Loans		16	20
Total		6,292	7,042
Commercial loans: | Non-investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		749	738
2020		459	474
2019		368	228
2018		168	301
2017		195	129
Prior		2,635	2,002
Revolving Loans		3,077	4,717
Revolving Loans Converted to Term Loans		162	275
Total		7,813	8,864
Commercial loans: | Non-investment grade | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2021		17	43
2020		1	18
2019		14	144
2018		16	0
2017		8	74
Prior		710	1,532
Revolving Loans		636	1,561
Revolving Loans Converted to Term Loans		0	0
Total		1,402	3,372
Commercial loans: | Non-investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021		469	6
2020		110	268
2019		298	98
2018		0	0
2017		41	3
Prior		102	105
Revolving Loans		47	327
Revolving Loans Converted to Term Loans		0	0
Total		$ 1,067	$ 807

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2021 and 2020. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20212020(in millions)AssetsLoans$46 $10 Other assets55 79 Total assets$101 $89 LiabilitiesInterest, taxes and other liabilities$9 $10 Total liabilities$9 $10