Business Segments 1 - Group Reporting Basis to US GAAP Adjustments from previous table (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Interest Income		$ 2,559	$ 2,387		$ 2,471
Other Revenues	[1]	1,604	1,727		1,595
Provision for Credit Losses		(199)	(119)		494
Operating Expenses	[1]	3,633	3,333	[2]	3,278	[2]
Profit (Loss) before Income Tax Expense		729	900		294
Total Assets		203,375	220,313		246,506
Deposit Incentives [Member]
Segment Reporting Information [Line Items]
Net Interest Income		9
Other Revenues		0
Provision for Credit Losses		0
Operating Expenses		20
Profit (Loss) before Income Tax Expense		(11)
Total Assets		(10)
Derivative [Member]
Segment Reporting Information [Line Items]
Net Interest Income		0	0		0
Other Revenues		0	0		0
Provision for Credit Losses		0	0		0
Operating Expenses		0	0		0
Profit (Loss) before Income Tax Expense		0	0		0
Total Assets		(30,866)	(32,900)		(44,911)
Expected Credit Losses/Loan Impairment [Member]
Segment Reporting Information [Line Items]
Net Interest Income		(6)	(43)		(57)
Other Revenues		0	0		7
Provision for Credit Losses		118	(72)		(58)
Operating Expenses		0	0		1
Profit (Loss) before Income Tax Expense		(124)	29		7
Total Assets		(386)	(332)		(326)
Goodwill [Member]
Segment Reporting Information [Line Items]
Net Interest Income		0	0		0
Other Revenues		0	(1)		0
Provision for Credit Losses		0	0		0
Operating Expenses		0	0		0
Profit (Loss) before Income Tax Expense		0	(1)		0
Total Assets		347	347		348
Loan Origination [Member]
Segment Reporting Information [Line Items]
Net Interest Income		(29)	(19)		(21)
Other Revenues		(3)	0		0
Provision for Credit Losses		0	0		0
Operating Expenses		(14)	(14)		(19)
Profit (Loss) before Income Tax Expense		(18)	(5)		(2)
Total Assets		45	42		35
Loans Held for Sale [Member]
Segment Reporting Information [Line Items]
Net Interest Income		9	9		0
Other Revenues		6	141		(80)
Provision for Credit Losses		(3)	0		(20)
Operating Expenses		0	0		0
Profit (Loss) before Income Tax Expense		18	150		(60)
Total Assets		45	21		(31)
Pension and Other Postretirement Benefit Costs [Member]
Segment Reporting Information [Line Items]
Net Interest Income		0	0		0
Other Revenues		0	0		0
Provision for Credit Losses		0	0		0
Operating Expenses		8	94		19
Profit (Loss) before Income Tax Expense		(8)	(94)		(19)
Total Assets		(44)	(263)		(191)
Property [Member]
Segment Reporting Information [Line Items]
Net Interest Income		0	0		0
Other Revenues		0	0		0
Provision for Credit Losses		0	0		0
Operating Expenses		(8)	(11)		(19)
Profit (Loss) before Income Tax Expense		8	11		19
Total Assets		7	8		16
Securities Transferred to Held-to-maturity [Member]
Segment Reporting Information [Line Items]
Net Interest Income		0
Other Revenues		0
Provision for Credit Losses		0
Operating Expenses		0
Profit (Loss) before Income Tax Expense		0
Total Assets		(76)
Unquoted Equity Securities [Member]
Segment Reporting Information [Line Items]
Net Interest Income					0
Other Revenues					0
Provision for Credit Losses					0
Operating Expenses					0
Profit (Loss) before Income Tax Expense					0
Total Assets					(163)
Structured Notes and Deposits [Member]
Segment Reporting Information [Line Items]
Net Interest Income			0
Other Revenues			85
Provision for Credit Losses			0
Operating Expenses			0
Profit (Loss) before Income Tax Expense			85
Total Assets			0
Other [Member]
Segment Reporting Information [Line Items]
Net Interest Income		1	5		2
Other Revenues		(12)	(25)		(31)
Provision for Credit Losses		0	0		0
Operating Expenses		(3)	6		(8)
Profit (Loss) before Income Tax Expense		(8)	(26)		(21)
Total Assets		11	(1)		(11)
Total Adjustments [Member]
Segment Reporting Information [Line Items]
Net Interest Income		(16)	(48)		(76)
Other Revenues		(9)	200		(104)
Provision for Credit Losses		115	(72)		(78)
Operating Expenses		3	75		(26)
Profit (Loss) before Income Tax Expense		(143)	149		(76)
Total Assets		$ (30,927)	$ (33,078)		$ (45,234)

[1] Represents adjustments associated with differences between U.S. GAAP and the Group Reporting Basis. These adjustments, which are more fully described above, consist of the following: NetInterestIncome OtherRevenues Provisionfor CreditLosses OperatingExpenses Profit (Loss)before IncomeTax Expense TotalAssets (in millions)December 31, 2018 Deposit incentives$9 $— $— $20 $(11) $(10)Derivatives— — — — — (30,866)Expected credit losses / loan impairment(6) — 118 — (124) (386)Goodwill— — — — — 347Loan origination(29) (3) — (14) (18) 45Loans held for sale9 6 (3) — 18 45Pension and other postretirement benefit costs— — — 8 (8) (44)Property— — — (8) 8 7Securities transferred to held-to-maturity— — — — — (76)Other1 (12) — (3) (8) 11Total adjustments$(16) $(9) $115 $3 $(143) $(30,927) December 31, 2017 Derivatives$— $— $— $— $— $(32,900)Expected credit losses / loan impairment(43) — (72) — 29 (332)Goodwill— (1) — — (1) 347Loan origination(19) — — (14) (5) 42Loans held for sale9 141 — — 150 21Pension and other postretirement benefit costs— — — 94 (94) (263)Property— — — (11) 11 8Structured notes and deposits— 85 — — 85 —Other5 (25) — 6 (26) (1)Total adjustments$(48) $200 $(72) $75 $149 $(33,078) December 31, 2016 Derivatives$— $— $— $— $— $(44,911)Expected credit losses / loan impairment(57) 7 (58) 1 7 (326)Goodwill— — — — — 348Loan origination(21) — — (19) (2) 35Loans held for sale— (80) (20) — (60) (31)Pension and other postretirement benefit costs— — — 19 (19) (191)Property— — — (19) 19 16Unquoted equity securities— — — — — (163)Other2 (31) — (8) (21) (11)Total adjustments$(76) $(104) $(78) $(26) $(76) $(45,234)

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