Business Segments - Summary on Reconciliation of Results Under IFRS to US GAAP (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021	Sep. 30, 2022		Sep. 30, 2021	Dec. 31, 2021	[1]
Operating Statistics [Line Items]
Net interest income (expense)	$ 543		$ 520	$ 1,552		$ 1,574
Other operating income	354		242	1,183		930
Total operating income	897		762	2,735		2,504
Provision for credit losses	25		(81)	105		(537)
Total income	872		843	2,630		3,041
Operating expenses	648		666	2,027		2,150
Income before income tax	224		177	603		891
Total assets	169,340	[1]	201,150	169,340	[1]	201,150	$ 189,232
Total loans, net	61,224	[1]	55,051	61,224	[1]	55,051	55,417
Goodwill	458	[1]	458	458	[1]	458	458
Total deposits	124,966	[1]	152,368	124,966	[1]	152,368	$ 143,032
Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	559		475	1,504		1,448
Other operating income	344		273	1,249		1,027
Total operating income (expense)	903		748	2,753		2,475
Expected credit losses / provision for credit losses	0		(42)	21		(216)
Total income	903		790	2,732		2,691
Operating expenses	626		654	1,962		2,088
Profit (loss) before income tax	277		136	770		603
Total assets	200,188		219,401	200,188		219,401
Total loans, net	60,224		54,334	60,224		54,334
Goodwill	358		358	358		358
Total deposits	120,627		137,131	120,627		137,131
Group Reporting Basis Adjustments
Operating Statistics [Line Items]
Net interest income (expense)	2		4	3		17
Other operating income	(23)		4	(54)		(2)
Total operating income (expense)	(21)		8	(51)		15
Expected credit losses / provision for credit losses	25		(39)	84		(321)
Total income	(46)		47	(135)		336
Operating expenses	7		6	32		48
Profit (loss) before income tax	(53)		41	(167)		288
Total assets	(30,848)		(18,251)	(30,848)		(18,251)
Total loans, net	(1,148)		(1,549)	(1,148)		(1,549)
Goodwill	100		100	100		100
Total deposits	(4,927)		(3,668)	(4,927)		(3,668)
Group Reporting Basis Reclassifications
Operating Statistics [Line Items]
Net interest income (expense)	(18)		41	45		109
Other operating income	33		(35)	(12)		(95)
Total operating income (expense)	15		6	33		14
Expected credit losses / provision for credit losses	0		0	0		0
Total income	15		6	33		14
Operating expenses	15		6	33		14
Profit (loss) before income tax	0		0	0		0
Total assets	0		0	0		0
Total loans, net	2,148		2,266	2,148		2,266
Goodwill	0		0	0		0
Total deposits	9,266		18,905	9,266		18,905
WPB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	211		202	565		616
Other operating income	62		57	257		215
Total operating income (expense)	273		259	822		831
Expected credit losses / provision for credit losses	(19)		(35)	(21)		(36)
Total income	292		294	843		867
Operating expenses	187		279	626		921
Profit (loss) before income tax	105		15	217		(54)
Total assets	42,954		69,021	42,954		69,021
Total loans, net	22,435		22,046	22,435		22,046
Goodwill	0		0	0		0
Total deposits	34,549		39,762	34,549		39,762
CMB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	253		200	658		580
Other operating income	65		70	221		208
Total operating income (expense)	318		270	879		788
Expected credit losses / provision for credit losses	(17)		24	10		(26)
Total income	335		246	869		814
Operating expenses	142		134	432		437
Profit (loss) before income tax	193		112	437		377
Total assets	51,555		46,226	51,555		46,226
Total loans, net	25,816		20,998	25,816		20,998
Goodwill	358		358	358		358
Total deposits	39,460		45,239	39,460		45,239
GB
Operating Statistics [Line Items]
Profit (loss) before income tax			108			420
Total assets			10,301			10,301
Total deposits			49,465			49,465
GB | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	137		75	321		237
Other operating income	52		96	306		314
Total operating income (expense)	189		171	627		551
Expected credit losses / provision for credit losses	37		(31)	32		(153)
Total income	152		202	595		704
Operating expenses	116		94	348		284
Profit (loss) before income tax	36		108	247		420
Total assets	11,845		10,301	11,845		10,301
Total loans, net	11,147		10,063	11,147		10,063
Goodwill	0		0	0		0
Total deposits	43,475		49,465	43,475		49,465
MSS
Operating Statistics [Line Items]
Profit (loss) before income tax			14			50
Total assets			41,193			41,193
Total deposits			1,719			1,719
MSS | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	(35)		11	(19)		36
Other operating income	146		69	388		226
Total operating income (expense)	111		80	369		262
Expected credit losses / provision for credit losses	0		0	0		0
Total income	111		80	369		262
Operating expenses	67		66	216		212
Profit (loss) before income tax	44		14	153		50
Total assets	52,044		41,193	52,044		41,193
Total loans, net	125		151	125		151
Goodwill	0		0	0		0
Total deposits	1,153		1,719	1,153		1,719
GBM Other
Operating Statistics [Line Items]
Profit (loss) before income tax			(19)			(21)
Total assets			51,049			51,049
Total deposits			946			946
GBM Other | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	(3)		(12)	(4)		(18)
Other operating income	17		19	67		73
Total operating income (expense)	14		7	63		55
Expected credit losses / provision for credit losses	(1)		0	0		(1)
Total income	15		7	63		56
Operating expenses	20		26	65		77
Profit (loss) before income tax	(5)		(19)	(2)		(21)
Total assets	39,494		51,049	39,494		51,049
Total loans, net	701		1,076	701		1,076
Goodwill	0		0	0		0
Total deposits	1,990		946	1,990		946
CC | Operating Segments
Operating Statistics [Line Items]
Net interest income (expense)	(4)		(1)	(17)		(3)
Other operating income	2		(38)	10		(9)
Total operating income (expense)	(2)		(39)	(7)		(12)
Expected credit losses / provision for credit losses	0		0	0		0
Total income	(2)		(39)	(7)		(12)
Operating expenses	94		55	275		157
Profit (loss) before income tax	(96)		(94)	(282)		(169)
Total assets	2,296		1,611	2,296		1,611
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 September 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. September 30, 2022December 31, 2021(in millions)AssetsLoans$127 $46 Other assets44 55 Total assets$171 $101 LiabilitiesInterest, taxes and other liabilities$26 $9 Total liabilities$26 $9