Acquisitions and Divestitures - Additional Information - 2014 Activity - Argentina Divestiture (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	0 Months Ended
	Dec. 31, 2014	Mar. 12, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of operations	$ 1,300
Argentina [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of operations		800
Liabilities assumed		$ 52
Debt assumed beginning date		Jun. 30, 2013