Loans - Summary of Criticized Assets for Commercial Loans (Detail) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total	[1]	$ 58,610	$ 55,864
Commercial loans:
Financing Receivable, Credit Quality Indicator [Line Items]
2022		844	3,735
2021		3,473	2,458
2020		2,336	3,778
2019		3,374	2,590
2018		2,454	1,184
Prior		12,764	11,747
Revolving Loans		16,997	14,071
Revolving Loans Converted to Term Loans		212	233
Total		42,454	39,796
Commercial loans: | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2022		315	969
2021		992	653
2020		622	2,516
2019		2,146	2,116
2018		1,936	593
Prior		1,937	1,325
Revolving Loans		56	46
Revolving Loans Converted to Term Loans		16	16
Total		8,020	8,234
Commercial loans: | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		197	1,630
2021		1,384	713
2020		646	608
2019		661	220
2018		213	238
Prior		4,697	4,757
Revolving Loans		7,311	5,575
Revolving Loans Converted to Term Loans		196	217
Total		15,305	13,958
Commercial loans: | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		322	547
2021		581	540
2020		525	203
2019		149	80
2018		100	243
Prior		4,963	4,620
Revolving Loans		5,308	4,876
Revolving Loans Converted to Term Loans		0	0
Total		11,948	11,109
Commercial loans: | Other commercial:
Financing Receivable, Credit Quality Indicator [Line Items]
2022		10	589
2021		516	552
2020		543	451
2019		418	174
2018		205	110
Prior		1,167	1,045
Revolving Loans		4,322	3,574
Revolving Loans Converted to Term Loans		0	0
Total		7,181	6,495
Commercial loans: | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	8
2021		1	20
2020		361	829
2019		531	841
2018		753	427
Prior		1,588	1,370
Revolving Loans		990	983
Revolving Loans Converted to Term Loans		44	19
Total		4,268	4,497
Commercial loans: | Criticized | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	1
2020		91	702
2019		389	752
2018		695	398
Prior		1,190	773
Revolving Loans		20	20
Revolving Loans Converted to Term Loans		12	11
Total		2,397	2,657
Commercial loans: | Criticized | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		1	19
2020		38	127
2019		125	89
2018		58	29
Prior		368	528
Revolving Loans		676	613
Revolving Loans Converted to Term Loans		32	8
Total		1,298	1,413
Commercial loans: | Criticized | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	8
2021		0	0
2020		232	0
2019		17	0
2018		0	0
Prior		23	62
Revolving Loans		269	310
Revolving Loans Converted to Term Loans		0	0
Total		541	380
Commercial loans: | Criticized | Other commercial:
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	0
2019		0	0
2018		0	0
Prior		7	7
Revolving Loans		25	40
Revolving Loans Converted to Term Loans		0	0
Total		32	47
Commercial loans: | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	8
2021		0	1
2020		100	441
2019		266	547
2018		478	116
Prior		502	548
Revolving Loans		146	220
Revolving Loans Converted to Term Loans		16	0
Total		1,508	1,881
Commercial loans: | Special mention | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		90	350
2019		175	487
2018		448	90
Prior		324	259
Revolving Loans		0	0
Revolving Loans Converted to Term Loans		1	0
Total		1,038	1,186
Commercial loans: | Special mention | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	1
2020		10	91
2019		91	60
2018		30	26
Prior		166	274
Revolving Loans		110	173
Revolving Loans Converted to Term Loans		15	0
Total		422	625
Commercial loans: | Special mention | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	8
2021		0	0
2020		0	0
2019		0	0
2018		0	0
Prior		8	8
Revolving Loans		36	47
Revolving Loans Converted to Term Loans		0	0
Total		44	63
Commercial loans: | Special mention | Other commercial:
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	0
2019		0	0
2018		0	0
Prior		4	7
Revolving Loans		0	0
Revolving Loans Converted to Term Loans		0	0
Total		4	7
Commercial loans: | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		1	19
2020		261	308
2019		189	272
2018		253	311
Prior		1,061	741
Revolving Loans		807	716
Revolving Loans Converted to Term Loans		28	19
Total		2,600	2,386
Commercial loans: | Substandard | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	1
2020		1	272
2019		138	263
2018		245	308
Prior		855	461
Revolving Loans		20	20
Revolving Loans Converted to Term Loans		11	11
Total		1,270	1,336
Commercial loans: | Substandard | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		1	18
2020		28	36
2019		34	9
2018		8	3
Prior		188	226
Revolving Loans		545	424
Revolving Loans Converted to Term Loans		17	8
Total		821	724
Commercial loans: | Substandard | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		232	0
2019		17	0
2018		0	0
Prior		15	54
Revolving Loans		217	232
Revolving Loans Converted to Term Loans		0	0
Total		481	286
Commercial loans: | Substandard | Other commercial:
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	0
2019		0	0
2018		0	0
Prior		3	0
Revolving Loans		25	40
Revolving Loans Converted to Term Loans		0	0
Total		28	40
Commercial loans: | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	80
2019		76	22
2018		22	0
Prior		25	81
Revolving Loans		37	47
Revolving Loans Converted to Term Loans		0	0
Total		160	230
Commercial loans: | Doubtful | Real Estate, including Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	80
2019		76	2
2018		2	0
Prior		11	53
Revolving Loans		0	0
Revolving Loans Converted to Term Loans		0	0
Total		89	135
Commercial loans: | Doubtful | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	0
2019		0	20
2018		20	0
Prior		14	28
Revolving Loans		21	16
Revolving Loans Converted to Term Loans		0	0
Total		55	64
Commercial loans: | Doubtful | Global banking
Financing Receivable, Credit Quality Indicator [Line Items]
2022		0	0
2021		0	0
2020		0	0
2019		0	0
2018		0	0
Prior		0	0
Revolving Loans		16	31
Revolving Loans Converted to Term Loans		0	0
Total		$ 16	$ 31

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at March 31, 2022 and December 31, 2021. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. March 31, 2022December 31, 2021(in millions)AssetsLoans$128 $46 Other assets51 55 Total assets$179 $101 LiabilitiesInterest, taxes and other liabilities$31 $9 Total liabilities$31 $9