Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Property Plant And Equipment [Line Items]
Property, plant and equipment, Gross	$ 203	$ 175
Less: accumulated depreciation	(60)	(51)
Property, plant and equipment, net	143	124
Information Technology Assets [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, Gross	$ 51	49
Information Technology Assets [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	2 years
Information Technology Assets [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	7 years
Operating Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, Gross	$ 59	51
Operating Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	3 years
Operating Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	15 years
Buildings and Land (Indefinite Life) [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, Gross	$ 90	73
Buildings and Land (Indefinite Life) [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	5 years
Buildings and Land (Indefinite Life) [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	35 years
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, Gross	$ 3	$ 2