CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at beginning of period at Dec. 31, 2013		$ 1,565
Balance at end of period at Dec. 31, 2014	$ 16,967	1,565
Balance at beginning of period at Dec. 31, 2013			$ 0	$ 14,106	$ 952	$ (159)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock issuance		0
Preferred stock redemption		$ 0
Excess of consideration received over book value on sale of London Branch precious metals business to an HSBC affiliate, net of tax				60
Capital contribution from parent				0
Employee benefit plans				4
Net income	354				354
Cash dividends declared on preferred stock					(73)
Other comprehensive income (loss), net of tax	158					158
Balance at end of period at Dec. 31, 2014	15,402		$ 0	14,170	1,233	(1)
Number of shares at beginning of period at Dec. 31, 2013		25,947,500	713
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares of stock issued to parent		0	0
Number of shares of preferred stock redeemed		0
Number of shares at end of period at Dec. 31, 2014		25,947,500	713
Balance at end of period at Dec. 31, 2015	20,525	$ 1,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock issuance		0
Preferred stock redemption		$ (300)
Excess of consideration received over book value on sale of London Branch precious metals business to an HSBC affiliate, net of tax				0
Capital contribution from parent				4,000
Employee benefit plans				(1)
Net income	330				330
Cash dividends declared on preferred stock					(65)
Other comprehensive income (loss), net of tax	(406)					(406)
Balance at end of period at Dec. 31, 2015	19,260		$ 0	18,169	1,498	(407)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares of stock issued to parent		0	1
Number of shares of preferred stock redeemed		(4,500,000)
Number of shares at end of period at Dec. 31, 2015		21,447,500	714
Balance at end of period at Dec. 31, 2016	20,355	$ 1,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock issuance		1,265
Preferred stock redemption		$ (1,265)
Excess of consideration received over book value on sale of London Branch precious metals business to an HSBC affiliate, net of tax				0
Capital contribution from parent				0
Employee benefit plans				(21)
Net income	129				129
Cash dividends declared on preferred stock					(67)
Other comprehensive income (loss), net of tax	(211)					(211)
Balance at end of period at Dec. 31, 2016	$ 19,090		$ 0	$ 18,148	$ 1,560	$ (618)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of shares of stock issued to parent		1,265	0
Number of shares of preferred stock redeemed		(21,447,500)
Number of shares at end of period at Dec. 31, 2016		1,265	714