Loans - Credit Risk Profile of Commercial Loans (Detail) - USD ($) $ in Millions		Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total	[1]	$ 57,945	$ 59,380
Commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		1,010	4,748
One year prior to current year		4,165	2,485
Two years prior to current year		2,697	1,814
Three years prior to current year		1,579	3,109
Four years prior to current year		2,800	2,311
Prior		12,750	11,997
Revolving Loans		14,533	15,143
Revolving Loans Converted to Term Loans		277	210
Total		39,811	41,817
Commercial loans | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		56	1,315
One year prior to current year		1,262	854
Two years prior to current year		960	520
Three years prior to current year		388	1,714
Four years prior to current year		1,524	1,803
Prior		2,951	1,712
Revolving Loans		41	42
Revolving Loans Converted to Term Loans		3	3
Total		7,185	7,963
Commercial loans | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		490	1,116
One year prior to current year		1,103	828
Two years prior to current year		837	475
Three years prior to current year		328	815
Four years prior to current year		647	308
Prior		4,784	5,019
Revolving Loans		7,706	7,307
Revolving Loans Converted to Term Loans		274	207
Total		16,169	16,075
Commercial loans | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		448	2,034
One year prior to current year		1,512	449
Two years prior to current year		610	212
Three years prior to current year		162	177
Four years prior to current year		209	114
Prior		4,105	4,152
Revolving Loans		3,081	3,440
Revolving Loans Converted to Term Loans		0	0
Total		10,127	10,578
Commercial loans | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		16	283
One year prior to current year		288	354
Two years prior to current year		290	607
Three years prior to current year		701	403
Four years prior to current year		420	86
Prior		910	1,114
Revolving Loans		3,705	4,354
Revolving Loans Converted to Term Loans		0	0
Total		6,330	7,201
Commercial loans | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		687	2,652
One year prior to current year		1,951	1,055
Two years prior to current year		1,071	1,157
Three years prior to current year		945	849
Four years prior to current year		972	1,012
Prior		7,422	6,882
Revolving Loans		9,922	10,773
Revolving Loans Converted to Term Loans		34	21
Total		23,004	24,401
Commercial loans | Investment grade | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		0	80
One year prior to current year		20	45
Two years prior to current year		25	305
Three years prior to current year		188	178
Four years prior to current year		115	783
Prior		994	278
Revolving Loans		0	0
Revolving Loans Converted to Term Loans		0	0
Total		1,342	1,669
Commercial loans | Investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		374	491
One year prior to current year		325	484
Two years prior to current year		495	122
Three years prior to current year		61	444
Four years prior to current year		362	71
Prior		2,556	2,758
Revolving Loans		3,647	3,657
Revolving Loans Converted to Term Loans		34	21
Total		7,854	8,048
Commercial loans | Investment grade | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		297	1,814
One year prior to current year		1,376	449
Two years prior to current year		481	212
Three years prior to current year		157	146
Four years prior to current year		184	84
Prior		3,129	2,911
Revolving Loans		2,652	3,006
Revolving Loans Converted to Term Loans		0	0
Total		8,276	8,622
Commercial loans | Investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		16	267
One year prior to current year		230	77
Two years prior to current year		70	518
Three years prior to current year		539	81
Four years prior to current year		311	74
Prior		743	935
Revolving Loans		3,623	4,110
Revolving Loans Converted to Term Loans		0	0
Total		5,532	6,062
Commercial loans | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		323	2,096
One year prior to current year		2,214	1,430
Two years prior to current year		1,626	657
Three years prior to current year		634	2,260
Four years prior to current year		1,828	1,299
Prior		5,328	5,115
Revolving Loans		4,611	4,370
Revolving Loans Converted to Term Loans		243	189
Total		16,807	17,416
Commercial loans | Non-investment grade | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		56	1,235
One year prior to current year		1,242	809
Two years prior to current year		935	215
Three years prior to current year		200	1,536
Four years prior to current year		1,409	1,020
Prior		1,957	1,434
Revolving Loans		41	42
Revolving Loans Converted to Term Loans		3	3
Total		5,843	6,294
Commercial loans | Non-investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		116	625
One year prior to current year		778	344
Two years prior to current year		342	353
Three years prior to current year		267	371
Four years prior to current year		285	237
Prior		2,228	2,261
Revolving Loans		4,059	3,650
Revolving Loans Converted to Term Loans		240	186
Total		8,315	8,027
Commercial loans | Non-investment grade | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		151	220
One year prior to current year		136	0
Two years prior to current year		129	0
Three years prior to current year		5	31
Four years prior to current year		25	30
Prior		976	1,241
Revolving Loans		429	434
Revolving Loans Converted to Term Loans		0	0
Total		1,851	1,956
Commercial loans | Non-investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		0	16
One year prior to current year		58	277
Two years prior to current year		220	89
Three years prior to current year		162	322
Four years prior to current year		109	12
Prior		167	179
Revolving Loans		82	244
Revolving Loans Converted to Term Loans		0	0
Total		$ 798	$ 1,139

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at June 30, 2023 and December 31, 2022. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. June 30, 2023December 31, 2022(in millions)AssetsLoans, net$186 $162 Other assets40 44 Total assets$226 $206 LiabilitiesInterest, taxes and other liabilities$35 $22 Total liabilities$35 $22