Fair Value Measurement - Assets and Liabilities Remeasured and Disclosed at Fair Value on Recurring Basis (Detail) - Fair Value Measurements, Recurring [Member] - Commodity Contracts [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Net Asset (Liability)	$ (2)	$ (3)
Level 2 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Net Asset (Liability)	$ (2)	$ (3)