Amounts to be Reflected as Component of Net Periodic Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Information	21
Net actuarial loss	$ 5
Prior service cost	(4)
Total	$ 1
United States Pension Plans of US Entity, Defined Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Information	50