Business Segments - Summary on Reconciliation of Results Under IFRS to US GAAP (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021	Dec. 31, 2021
Operating Statistics [Line Items]
Net interest income (expense)	$ 532		$ 523	$ 1,009		$ 1,054
Other operating income	343		304	829		688
Total operating income	875		827	1,838		1,742
Provision for credit losses	69		(229)	80		(456)
Total income	806		1,056	1,758		2,198
Operating expenses	693		802	1,379		1,484
Income before income tax	113		254	379		714
Total assets	171,232	[1]	194,888	171,232	[1]	194,888	$ 189,232	[1]
Total loans, net	61,264		53,851	61,264		53,851
Goodwill	458		458	458		458	458	[1]
Total deposits	127,263		147,365	127,263		147,365	$ 143,032
Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	500		480	945		973
Other operating income	377		344	905		754
Total operating income (expense)	877		824	1,850		1,727
Expected credit losses / provision for credit losses	46		(83)	21		(174)
Total income	831		907	1,829		1,901
Operating expenses	671		765	1,336		1,434
Profit (loss) before income tax	160		142	493		467
Total assets	192,198		214,821	192,198		214,821
Total loans, net	59,887		53,528	59,887		53,528
Goodwill	358		358	358		358
Total deposits	122,162		131,078	122,162		131,078
Group Reporting Basis Adjustments
Operating Statistics [Line Items]
Net interest income (expense)	0		9	1		13
Other operating income	(11)		(11)	(31)		(6)
Total operating income (expense)	(11)		(2)	(30)		7
Expected credit losses / provision for credit losses	23		(146)	59		(282)
Total income	(34)		144	(89)		289
Operating expenses	13		32	25		42
Profit (loss) before income tax	(47)		112	(114)		247
Total assets	(20,966)		(19,933)	(20,966)		(19,933)
Total loans, net	(890)		(2,261)	(890)		(2,261)
Goodwill	100		100	100		100
Total deposits	(3,434)		(4,213)	(3,434)		(4,213)
Group Reporting Basis Reclassifications
Operating Statistics [Line Items]
Net interest income (expense)	32		34	63		68
Other operating income	(23)		(29)	(45)		(60)
Total operating income (expense)	9		5	18		8
Expected credit losses / provision for credit losses	0		0	0		0
Total income	9		5	18		8
Operating expenses	9		5	18		8
Profit (loss) before income tax	0		0	0		0
Total assets	0		0	0		0
Total loans, net	2,267		2,584	2,267		2,584
Goodwill	0		0	0		0
Total deposits	8,535		20,500	8,535		20,500
WPB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	185		205	354		414
Other operating income	32		71	195		158
Total operating income (expense)	217		276	549		572
Expected credit losses / provision for credit losses	(6)		1	(2)		(1)
Total income	223		275	551		573
Operating expenses	197		355	439		642
Profit (loss) before income tax	26		(80)	112		(69)
Total assets	43,510		64,120	43,510		64,120
Total loans, net	21,994		21,778	21,994		21,778
Goodwill	0		0	0		0
Total deposits	37,395		38,416	37,395		38,416
CMB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	220		190	405		380
Other operating income	73		72	156		138
Total operating income (expense)	293		262	561		518
Expected credit losses / provision for credit losses	54		(12)	27		(50)
Total income	239		274	534		568
Operating expenses	143		153	290		303
Profit (loss) before income tax	96		121	244		265
Total assets	52,351		43,360	52,351		43,360
Total loans, net	25,454		21,517	25,454		21,517
Goodwill	358		358	358		358
Total deposits	40,170		43,340	40,170		43,340
GB
Operating Statistics [Line Items]
Profit (loss) before income tax			168			312
Total assets			9,851			9,851
Total deposits			46,244			46,244
GB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	106		79	184		162
Other operating income	130		113	254		218
Total operating income (expense)	236		192	438		380
Expected credit losses / provision for credit losses	(3)		(72)	(5)		(122)
Total income	239		264	443		502
Operating expenses	115		96	232		190
Profit (loss) before income tax	124		168	211		312
Total assets	12,385		9,851	12,385		9,851
Total loans, net	11,780		9,396	11,780		9,396
Goodwill	0		0	0		0
Total deposits	41,995		46,244	41,995		46,244
MSS
Operating Statistics [Line Items]
Profit (loss) before income tax			(12)			36
Total assets			50,626			50,626
Total deposits			2,170			2,170
MSS | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	0		12	16		25
Other operating income	100		41	242		157
Total operating income (expense)	100		53	258		182
Expected credit losses / provision for credit losses	0		0	0		0
Total income	100		53	258		182
Operating expenses	80		65	149		146
Profit (loss) before income tax	20		(12)	109		36
Total assets	40,413		50,626	40,413		50,626
Total loans, net	131		360	131		360
Goodwill	0		0	0		0
Total deposits	1,193		2,170	1,193		2,170
GBM Other
Operating Statistics [Line Items]
Profit (loss) before income tax			(1)			(2)
Total assets			45,044			45,044
Total deposits			908			908
GBM Other | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	1		(5)	(1)		(6)
Other operating income	26		29	50		54
Total operating income (expense)	27		24	49		48
Expected credit losses / provision for credit losses	1		0	1		(1)
Total income	26		24	48		49
Operating expenses	21		25	45		51
Profit (loss) before income tax	5		(1)	3		(2)
Total assets	41,225		45,044	41,225		45,044
Total loans, net	528		477	528		477
Goodwill	0		0	0		0
Total deposits	1,409		908	1,409		908
CC | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	(12)		(1)	(13)		(2)
Other operating income	16		18	8		29
Total operating income (expense)	4		17	(5)		27
Expected credit losses / provision for credit losses	0		0	0		0
Total income	4		17	(5)		27
Operating expenses	115		71	181		102
Profit (loss) before income tax	(111)		(54)	(186)		(75)
Total assets	2,314		1,820	2,314		1,820
Total loans, net	0		0	0		0
Goodwill	0		0	0		0
Total deposits	$ 0		$ 0	$ 0		$ 0

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at June 30, 2022 and December 31, 2021. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. June 30, 2022December 31, 2021(in millions)AssetsLoans$118 $46 Other assets46 55 Total assets$164 $101 LiabilitiesInterest, taxes and other liabilities$28 $9 Total liabilities$28 $9