Pensions and Other Postretirement Benefits-Projected Benefit Obligation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
HSBC North America Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 7	$ 4	$ 15
Interest cost	70	71	67
Postretirement Plans Other Than Pensions [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Accumulated benefit obligation at beginning of year	59	70
Service cost	0	1	1
Interest cost	3	2	3
Actuarial losses (gains)	5	(8)
Benefits paid	(5)	(6)
Accumulated benefit obligation at end of year	62	59	70
Hsbc North America [Member] | HSBC North America Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of year	3,892	4,374
Accumulated benefit obligation at beginning of year	3,892
Service cost	16	11
Interest cost	177	176
Actuarial losses (gains)	465	(496)
Benefits paid	(185)	(173)
Projected benefit obligation at end of year	4,365	3,892
Accumulated benefit obligation at end of year	$ 4,365	$ 3,892