Pensions and Other Postretirement Benefits-Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Additional contribution	$ 74
Postretirement Plans Other Than Pensions [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost on projected benefit obligation	1	1
Net periodic benefit cost	1	1
HSBC USA Inc [Member] | HSBC North America Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost – benefits earned during the period	1	1
Interest cost on projected benefit obligation	18	17
Expected return on assets	(20)	(20)
Recognized losses	9	13
Net periodic benefit cost	$ 8	$ 11