Business Segments 1 - Group Reporting Basis to US GAAP Adjustments from previous table (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income	[1]	$ 2,471	$ 2,317	$ 2,236
Group Reporting Basis Other revenues		1,523	1,947	1,899
Group Reporting Basis Provision for credit losses		494	264	127
Group Reporting Basis Operating expenses	[2]	3,206	3,245	3,582
Group Reporting Basis Income (loss) from continuing operations before income tax		294	755	426
Group Reporting Basis Total assets		246,506	234,530	239,636
Unquoted Equity Securities [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	0	0
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		0	0	0
Group Reporting Basis Income (loss) from continuing operations before income tax		0	0	0
Group Reporting Basis Total assets		(163)	(228)	(195)
Derivatives [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	(3)	(4)
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		0	0	0
Group Reporting Basis Income (loss) from continuing operations before income tax		0	(3)	(4)
Group Reporting Basis Total assets		(44,911)	(46,245)	(53,973)
Loan Impairment [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		(57)	(61)	(56)
Group Reporting Basis Other revenues		7	3	1
Group Reporting Basis Provision for credit losses		(58)	132	120
Group Reporting Basis Operating expenses		1	1	1
Group Reporting Basis Income (loss) from continuing operations before income tax		7	(191)	(176)
Group Reporting Basis Total assets		(326)	(329)	(204)
Property [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	0	0
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		(19)	(19)	(16)
Group Reporting Basis Income (loss) from continuing operations before income tax		19	19	16
Group Reporting Basis Total assets		16	21	28
Pension and Other Postretirement Benefit Costs [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	0	0
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		19	15	11
Group Reporting Basis Income (loss) from continuing operations before income tax		(19)	(15)	(11)
Group Reporting Basis Total assets		(191)	(177)	(166)
Goodwill [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	0	0
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		0	0	0
Group Reporting Basis Income (loss) from continuing operations before income tax		0	0	0
Group Reporting Basis Total assets		348	348	348
Litigation [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		0	0	0
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		(8)	(2)	(135)
Group Reporting Basis Income (loss) from continuing operations before income tax		8	2	135
Group Reporting Basis Total assets		(3)	0	1
Loan Origination [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		(21)	(22)
Group Reporting Basis Other revenues		0	(3)
Group Reporting Basis Provision for credit losses		0	0
Group Reporting Basis Operating expenses		(19)	(47)
Group Reporting Basis Income (loss) from continuing operations before income tax		(2)	22
Group Reporting Basis Total assets		35	49
Loans Held for Sale [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0
Group Reporting Basis Other revenues		(80)	(16)
Group Reporting Basis Provision for credit losses		(20)	(2)
Group Reporting Basis Operating expenses		0	0
Group Reporting Basis Income (loss) from continuing operations before income tax		(60)	(14)
Group Reporting Basis Total assets		(31)	(4)
Sale of London Branch Precious Metals Business [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income				0
Group Reporting Basis Other revenues				(98)
Group Reporting Basis Provision for credit losses				0
Group Reporting Basis Operating expenses				0
Group Reporting Basis Income (loss) from continuing operations before income tax				(98)
Group Reporting Basis Total assets				0
Low Income Housing Tax Credit [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		0	0	0
Group Reporting Basis Other revenues		(9)	(12)	(16)
Group Reporting Basis Provision for credit losses		0	0	0
Group Reporting Basis Operating expenses		0	0	0
Group Reporting Basis Income (loss) from continuing operations before income tax		(9)	(12)	(16)
Group Reporting Basis Total assets		0	0	0
Other [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income		2	5	(18)
Group Reporting Basis Other revenues		(22)	(8)	(15)
Group Reporting Basis Provision for credit losses		0	0	(40)
Group Reporting Basis Operating expenses		0	0	(19)
Group Reporting Basis Income (loss) from continuing operations before income tax		(20)	(3)	26
Group Reporting Basis Total assets		(8)	(4)	23
Group Reporting Basis Adjustments [Member]
Segment Reporting Information [Line Items]
Group Reporting Basis Net interest income	[1],[3]	(76)	(78)	(74)
Group Reporting Basis Other revenues	[3]	(104)	(39)	(132)
Group Reporting Basis Provision for credit losses	[3]	(78)	130	80
Group Reporting Basis Operating expenses	[2],[3]	(26)	(52)	(158)
Group Reporting Basis Income (loss) from continuing operations before income tax	[3]	(76)	(195)	(128)
Group Reporting Basis Total assets	[3]	$ (45,234)	$ (46,569)	$ (54,138)

[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 the segments.

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

[3] Represents adjustments associated with differences between U.S. GAAP and the Group Reporting Basis.