Loans - Credit Risk Profile of Commercial Loans (Detail) - USD ($) $ in Millions		Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total	[1]	$ 64,503	$ 62,753
Commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		2,517	3,852
One year prior to current year		4,953	3,821
Two years prior to current year		2,312	3,112
Three years prior to current year		2,572	3,004
Four years prior to current year		2,029	1,042
Prior		11,754	11,633
Revolving Loans		15,416	14,289
Revolving Loans Converted to Term Loans		317	298
Total		41,870	41,051
Commercial loans | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		583	1,035
One year prior to current year		1,471	946
Two years prior to current year		508	1,109
Three years prior to current year		915	882
Four years prior to current year		580	262
Prior		2,151	2,339
Revolving Loans		31	36
Revolving Loans Converted to Term Loans		2	3
Total		6,241	6,612
Commercial loans | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		1,786	2,324
One year prior to current year		3,043	2,785
Two years prior to current year		1,698	1,722
Three years prior to current year		1,454	1,986
Four years prior to current year		1,373	276
Prior		8,090	7,729
Revolving Loans		8,043	8,309
Revolving Loans Converted to Term Loans		315	295
Total		25,802	25,426
Commercial loans | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		148	493
One year prior to current year		439	90
Two years prior to current year		106	281
Three years prior to current year		203	136
Four years prior to current year		76	504
Prior		1,513	1,565
Revolving Loans		7,342	5,944
Revolving Loans Converted to Term Loans		0	0
Total		9,827	9,013
Commercial loans | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		1,465	1,757
One year prior to current year		2,845	2,046
Two years prior to current year		1,277	1,149
Three years prior to current year		980	1,443
Four years prior to current year		1,039	575
Prior		6,847	6,911
Revolving Loans		11,237	10,535
Revolving Loans Converted to Term Loans		71	88
Total		25,761	24,504
Commercial loans | Investment grade | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		122	67
One year prior to current year		711	307
Two years prior to current year		283	27
Three years prior to current year		23	0
Four years prior to current year		196	165
Prior		525	757
Revolving Loans		10	0
Revolving Loans Converted to Term Loans		0	0
Total		1,870	1,323
Commercial loans | Investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		1,272	1,325
One year prior to current year		1,841	1,668
Two years prior to current year		939	981
Three years prior to current year		887	1,357
Four years prior to current year		767	190
Prior		5,190	4,896
Revolving Loans		4,708	4,752
Revolving Loans Converted to Term Loans		71	88
Total		15,675	15,257
Commercial loans | Investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		71	365
One year prior to current year		293	71
Two years prior to current year		55	141
Three years prior to current year		70	86
Four years prior to current year		76	220
Prior		1,132	1,258
Revolving Loans		6,519	5,783
Revolving Loans Converted to Term Loans		0	0
Total		8,216	7,924
Commercial loans | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		1,052	2,095
One year prior to current year		2,108	1,775
Two years prior to current year		1,035	1,963
Three years prior to current year		1,592	1,561
Four years prior to current year		990	467
Prior		4,907	4,722
Revolving Loans		4,179	3,754
Revolving Loans Converted to Term Loans		246	210
Total		16,109	16,547
Commercial loans | Non-investment grade | Real estate, including construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		461	968
One year prior to current year		760	639
Two years prior to current year		225	1,082
Three years prior to current year		892	882
Four years prior to current year		384	97
Prior		1,626	1,582
Revolving Loans		21	36
Revolving Loans Converted to Term Loans		2	3
Total		4,371	5,289
Commercial loans | Non-investment grade | Business and corporate banking
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		514	999
One year prior to current year		1,202	1,117
Two years prior to current year		759	741
Three years prior to current year		567	629
Four years prior to current year		606	86
Prior		2,900	2,833
Revolving Loans		3,335	3,557
Revolving Loans Converted to Term Loans		244	207
Total		10,127	10,169
Commercial loans | Non-investment grade | Other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Current year		77	128
One year prior to current year		146	19
Two years prior to current year		51	140
Three years prior to current year		133	50
Four years prior to current year		0	284
Prior		381	307
Revolving Loans		823	161
Revolving Loans Converted to Term Loans		0	0
Total		$ 1,611	$ 1,089

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at September 30, 2025 and December 31, 2024. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 15, "Variable Interest Entities," for additional information. September 30, 2025December 31, 2024(in millions)AssetsOther assets$7 $11 Total assets$7 $11 LiabilitiesInterest, taxes and other liabilities$14 $4 Total liabilities$14 $4