Pensions and Other Postretirement Benefits-Projected Benefit Obligation (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Postretirement Plans Other Than Pensions [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Accumulated benefit obligation at beginning of year		$ 62	$ 59
Interest cost		2	3	$ 2
Actuarial losses (gains)		4	5
Benefits paid		(4)	(5)
Plan amendments	[1]	(4)	0
Accumulated benefit obligation at end of year		$ 60	62	59
Remaining amortization period for plan amendment		8 years
Hsbc North America [Member] | HSBC North America Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Interest cost		$ 70	$ 70	$ 71

[1] During 2015, the substantial majority of our postretirement benefit plans were amended relating to post-65 retirees which resulted in a reduction of our postretirement benefit liability as the amendments eliminated future health cost increases which were previously included in the liability. This reduction is being amortized to postretirement benefit expense over the remaining estimated covered period for affected employees which is approximately 8 years.