Business Segments - Summary on Reconciliation of Results Under Ifrs to Us Gaap (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015		Dec. 31, 2015
Operating Statistics [Line Items]
Net interest income	[1]	$ 654		$ 606
Other operating income		462		464
Total operating income		1,116		1,070
Loan impairment charges		157		53
Total income		959		1,017
Operating expenses	[2]	726		777
Income before income tax		233		240
Total assets		203,784	[3]	201,594		$ 188,278	[3]
Total loans, net		80,709		80,755		82,005
Goodwill		1,612		1,612		1,612
Total deposits		126,303	[4]	119,094	[4]	$ 118,579
Adjustments/Reconciling Items [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	(2)		(5)
Group Reporting Basis Other operating income		2		5
Group Reporting Basis Total operating income		0		0
Group Reporting Basis Loan impairment charges		0		0
Group Reporting Basis Revenues		0		0
Group Reporting Basis Operating expenses	[2]	0		0
Group Reporting Basis Income (loss) from continuing operations before income tax		0		0
Group Reporting Basis Total assets		0		0
Group Reporting Basis Total loans, net		0		0
Group Reporting Basis Goodwill		0		0
Group Reporting Basis Total deposits	[4]	0		0
Total [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	634		554
Group Reporting Basis Other operating income		574		541
Group Reporting Basis Total operating income		1,208		1,095
Group Reporting Basis Loan impairment charges		232		40
Group Reporting Basis Revenues		976		1,055
Group Reporting Basis Operating expenses	[2]	729		794
Group Reporting Basis Income (loss) from continuing operations before income tax		247		261
Group Reporting Basis Total assets		253,889		258,511
Group Reporting Basis Total loans, net		76,849		76,316
Group Reporting Basis Goodwill		1,264		1,264
Group Reporting Basis Total deposits	[4]	96,900		94,084
Group Reporting Basis Adjustments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1],[5]	(19)		(14)
Group Reporting Basis Other operating income	[5]	(70)		(10)
Group Reporting Basis Total operating income	[5]	(89)		(24)
Group Reporting Basis Loan impairment charges	[5]	(69)		14
Group Reporting Basis Revenues	[5]	(20)		(38)
Group Reporting Basis Operating expenses	[2],[5]	(6)		(17)
Group Reporting Basis Income (loss) from continuing operations before income tax	[5]	(14)		(21)
Group Reporting Basis Total assets	[5]	(50,109)		(56,958)
Group Reporting Basis Total loans, net	[5]	4		891
Group Reporting Basis Goodwill	[5]	348		348
Group Reporting Basis Total deposits	[4],[5]	(5,195)		(5,975)
Group Reporting Basis Reclassifications [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1],[6]	39		66
Group Reporting Basis Other operating income	[6]	(42)		(67)
Group Reporting Basis Total operating income	[6]	(3)		(1)
Group Reporting Basis Loan impairment charges	[6]	(6)		(1)
Group Reporting Basis Revenues	[6]	3		0
Group Reporting Basis Operating expenses	[2],[6]	3		0
Group Reporting Basis Income (loss) from continuing operations before income tax	[6]	0		0
Group Reporting Basis Total assets	[6]	4		41
Group Reporting Basis Total loans, net	[6]	3,856		3,548
Group Reporting Basis Goodwill	[6]	0		0
Group Reporting Basis Total deposits	[4],[6]	34,598		30,985
RBWM [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	201		201
Group Reporting Basis Other operating income		80		88
Group Reporting Basis Total operating income		281		289
Group Reporting Basis Loan impairment charges		16		22
Group Reporting Basis Revenues		265		267
Group Reporting Basis Operating expenses	[2]	259		294
Group Reporting Basis Income (loss) from continuing operations before income tax		6		(27)
Group Reporting Basis Total assets		20,723		19,927
Group Reporting Basis Total loans, net		17,702		16,973
Group Reporting Basis Goodwill		581		581
Group Reporting Basis Total deposits	[4]	32,506		29,869
CMB [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	213		197
Group Reporting Basis Other operating income		73		76
Group Reporting Basis Total operating income		286		273
Group Reporting Basis Loan impairment charges		13		10
Group Reporting Basis Revenues		273		263
Group Reporting Basis Operating expenses	[2]	162		156
Group Reporting Basis Income (loss) from continuing operations before income tax		111		107
Group Reporting Basis Total assets		31,610		30,717
Group Reporting Basis Total loans, net		28,638		29,578
Group Reporting Basis Goodwill		358		358
Group Reporting Basis Total deposits	[4]	22,488		21,580
GBM [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	176		118
Group Reporting Basis Other operating income		219		266
Group Reporting Basis Total operating income		395		384
Group Reporting Basis Loan impairment charges		204		8
Group Reporting Basis Revenues		191		376
Group Reporting Basis Operating expenses	[2]	224		259
Group Reporting Basis Income (loss) from continuing operations before income tax		(33)		117
Group Reporting Basis Total assets		192,873		198,942
Group Reporting Basis Total loans, net		24,048		23,341
Group Reporting Basis Goodwill		0		0
Group Reporting Basis Total deposits	[4]	28,073		31,662
Group Reporting Basis Brokered Deposits				7,200
PB [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	51		49
Group Reporting Basis Other operating income		23		24
Group Reporting Basis Total operating income		74		73
Group Reporting Basis Loan impairment charges		(1)		0
Group Reporting Basis Revenues		75		73
Group Reporting Basis Operating expenses	[2]	58		58
Group Reporting Basis Income (loss) from continuing operations before income tax		17		15
Group Reporting Basis Total assets		8,221		8,121
Group Reporting Basis Total loans, net		6,461		6,424
Group Reporting Basis Goodwill		325		325
Group Reporting Basis Total deposits	[4]	13,813		10,973
Other [Member] | Operating Segments [Member]
Operating Statistics [Line Items]
Group Reporting Basis Net interest income	[1]	(5)		(6)
Group Reporting Basis Other operating income		177		82
Group Reporting Basis Total operating income		172		76
Group Reporting Basis Loan impairment charges		0		0
Group Reporting Basis Revenues		172		76
Group Reporting Basis Operating expenses	[2]	26		27
Group Reporting Basis Income (loss) from continuing operations before income tax		146		49
Group Reporting Basis Total assets		462		804
Group Reporting Basis Total loans, net		0		0
Group Reporting Basis Goodwill		0		0
Group Reporting Basis Total deposits	[4]	$ 20		$ 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 March 31, 2016 and December 31, 2015 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. Assets: Other assets $305 million and $320 million. Total assets $305 million and $320 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $68 million and $68 million. Total liabilities $160 million and $160 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 $7.2 billion of brokered deposits in the GB&M segment to debt at March 31, 2015 to conform with the 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.