Business Segments - Summary on Reconciliation of Results Under Ifrs to Us Gaap (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015		Jun. 30, 2014		Dec. 31, 2014
Operating Statistics [Line Items]
Net interest income	[1]	$ 626		$ 673		$ 1,232		$ 1,192
Other operating income		403		261		867		761
Total operating income		1,029		934		2,099		1,953
Loan impairment charges		(6)		85		47		101
Total income		1,035		849		2,052		1,852
Operating expenses	[2]	850		876		1,627		1,626
Income (loss) before income tax		185		(27)		425		226
Total assets		196,618	[3]	182,218		196,618	[3]	182,218		$ 185,539	[3]
Total loans, net		82,969		71,574		82,969		71,574		77,061
Goodwill		1,612		1,612		1,612		1,612		1,612
Total deposits		122,547	[3],[4]	115,521	[4]	122,547	[3],[4]	115,521	[4]	$ 116,118	[3]
Group Reporting Basis Adjustments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1],[5]	(18)		(16)		(32)		(31)
Group Reporting Basis Other operating income	[5]	(15)		(6)		(25)		(10)
Group Reporting Basis Total operating income	[5]	(33)		(22)		(57)		(41)
Group Reporting Basis Loan impairment charges	[5]	(27)		(52)		(13)		(48)
Group Reporting Basis Revenues	[5]	(6)		30		(44)		7
Group Reporting Basis Operating expenses	[2],[5]	(9)		76		(26)		68
Group Reporting Basis Income (loss) from continuing operations before income tax	[5]	3		(46)		(18)		(61)
Group Reporting Basis Total assets	[5]	(45,816)		(47,570)		(45,816)		(47,570)
Group Reporting Basis Total loans, net	[5]	906		1,693		906		1,693
Group Reporting Basis Goodwill	[5]	348		348		348		348
Group Reporting Basis Total deposits	[4],[5]	(4,512)		(3,128)		(4,512)		(3,128)
Group Reporting Basis Reclassifications [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1],[6]	64		36		130		57
Group Reporting Basis Other operating income	[6]	(63)		(43)		(130)		(69)
Group Reporting Basis Total operating income	[6]	1		(7)		0		(12)
Group Reporting Basis Loan impairment charges	[6]	(1)		(7)		(2)		(14)
Group Reporting Basis Revenues	[6]	2		0		2		2
Group Reporting Basis Operating expenses	[2],[6]	2		0		2		2
Group Reporting Basis Income (loss) from continuing operations before income tax	[6]	0		0		0		0
Group Reporting Basis Total assets	[6]	13		(236)		13		(236)
Group Reporting Basis Total loans, net	[6]	3,254		2,301		3,254		2,301
Group Reporting Basis Goodwill	[6]	0		0		0		0
Group Reporting Basis Total deposits	[4],[6]	31,602		25,462		31,602		25,462
Aggregate [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	580		653		1,134		1,166
Group Reporting Basis Other operating income		481		310		1,022		840
Group Reporting Basis Total operating income		1,061		963		2,156		2,006
Group Reporting Basis Loan impairment charges		22		144		62		163
Group Reporting Basis Revenues		1,039		819		2,094		1,843
Group Reporting Basis Operating expenses	[2]	857		800		1,651		1,556
Group Reporting Basis Income (loss) from continuing operations before income tax		182		19		443		287
Group Reporting Basis Total assets		242,421		230,024		242,421		230,024
Group Reporting Basis Total loans, net		78,809		67,580		78,809		67,580
Group Reporting Basis Goodwill		1,264		1,264		1,264		1,264
Group Reporting Basis Total deposits	[4]	95,457		93,187		95,457		93,187
Segment Reconciling Items [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	(3)		(4)		(8)		(9)
Group Reporting Basis Other operating income		3		4		8		9
Group Reporting Basis Total operating income		0		0		0		0
Group Reporting Basis Loan impairment charges		0		0		0		0
Group Reporting Basis Revenues		0		0		0		0
Group Reporting Basis Operating expenses	[2]	0		0		0		0
Group Reporting Basis Income (loss) from continuing operations before income tax		0		0		0		0
Group Reporting Basis Total assets		0		0		0		0
Group Reporting Basis Total loans, net		0		0		0		0
Group Reporting Basis Goodwill		0		0		0		0
Group Reporting Basis Total deposits	[4]	0		0		0		0
RBWM [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	195		212		392		410
Group Reporting Basis Other operating income		86		104		173		217
Group Reporting Basis Total operating income		281		316		565		627
Group Reporting Basis Loan impairment charges		15		21		37		23
Group Reporting Basis Revenues		266		295		528		604
Group Reporting Basis Operating expenses	[2]	300		298		581		577
Group Reporting Basis Income (loss) from continuing operations before income tax		(34)		(3)		(53)		27
Group Reporting Basis Total assets		19,987		19,169		19,987		19,169
Group Reporting Basis Total loans, net		17,039		16,315		17,039		16,315
Group Reporting Basis Goodwill		581		581		581		581
Group Reporting Basis Total deposits	[4]	30,504		29,138		30,504		29,138
CMB [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	211		202		412		389
Group Reporting Basis Other operating income		71		64		148		132
Group Reporting Basis Total operating income		282		266		560		521
Group Reporting Basis Loan impairment charges		4		83		14		90
Group Reporting Basis Revenues		278		183		546		431
Group Reporting Basis Operating expenses	[2]	185		174		354		332
Group Reporting Basis Income (loss) from continuing operations before income tax		93		9		192		99
Group Reporting Basis Total assets		31,940		26,467		31,940		26,467
Group Reporting Basis Total loans, net		30,783		25,239		30,783		25,239
Group Reporting Basis Goodwill		358		358		358		358
Group Reporting Basis Total deposits	[4]	21,844		22,135		21,844		22,135
GBM [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	132		109		250		206
Group Reporting Basis Other operating income		219		151		485		445
Group Reporting Basis Total operating income		351		260		735		651
Group Reporting Basis Loan impairment charges		4		40		12		55
Group Reporting Basis Revenues		347		220		723		596
Group Reporting Basis Operating expenses	[2]	264		239		523		478
Group Reporting Basis Income (loss) from continuing operations before income tax		83		(19)		200		118
Group Reporting Basis Total assets		181,541		175,330		181,541		175,330
Group Reporting Basis Total loans, net		24,489		19,957		24,489		19,957
Group Reporting Basis Goodwill		0		0		0		0
Group Reporting Basis Total deposits	[4]	30,343		30,092		30,343		30,092
Group Reporting Basis Brokered Deposits				1,800				1,800
PB [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	50		56		99		105
Group Reporting Basis Other operating income		27		25		51		50
Group Reporting Basis Total operating income		77		81		150		155
Group Reporting Basis Loan impairment charges		(1)		0		(1)		(5)
Group Reporting Basis Revenues		78		81		151		160
Group Reporting Basis Operating expenses	[2]	58		61		116		116
Group Reporting Basis Income (loss) from continuing operations before income tax		20		20		35		44
Group Reporting Basis Total assets		8,174		8,232		8,174		8,232
Group Reporting Basis Total loans, net		6,498		6,069		6,498		6,069
Group Reporting Basis Goodwill		325		325		325		325
Group Reporting Basis Total deposits	[4]	12,766		11,822		12,766		11,822
Other [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	(5)		78		(11)		65
Group Reporting Basis Other operating income		75		(38)		157		(13)
Group Reporting Basis Total operating income		70		40		146		52
Group Reporting Basis Loan impairment charges		0		0		0		0
Group Reporting Basis Revenues		70		40		146		52
Group Reporting Basis Operating expenses	[2]	50		28		77		53
Group Reporting Basis Income (loss) from continuing operations before income tax		20		12		69		(1)
Group Reporting Basis Total assets		779		826		779		826
Group Reporting Basis Total loans, net		0		0		0		0
Group Reporting Basis Goodwill		0		0		0		0
Group Reporting Basis Total deposits	[4]	$ 0		$ 0		$ 0		$ 0

[1] Net interest income of each segment represents the difference between actual interest earned on assets and interest paid on liabilities of the segment adjusted for a funding charge or credit. Segments are charged a cost to fund assets (e.g. customer loans) and receive a funding credit for funds provided (e.g. customer deposits) based on equivalent market rates. The objective of these charges/credits is to transfer interest rate risk from the segments to one centralized unit in Balance Sheet Management and more appropriately reflect the profitability of segments.

[2] Expenses for the segments include fully apportioned corporate overhead expenses.

[3] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of June 30, 2015 and December 31, 2014 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 216, "Variable Interest Entities," for additional information. Assets: Other assets $355 million and $380 million. Total assets $355 million and $380 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $84 million and $75 million. Total liabilities $176 million and $167 million, respectively.

[4] During the second quarter of 2015, we concluded that brokered deposits would be better presented as debt under the Group Reporting Basis. As a result, we reclassified $1.8 billion of brokered deposits in the GB&M segment to debt at June 30, 2014 to conform with current year presentation.

[5] Represents adjustments associated with differences between the Group Reporting Basis and the U.S. GAAP basis of accounting.

[6] Represents differences in financial statement presentation between Group Reporting Basis and U.S. GAAP.