Valuation and Qualifying Accounts - Description of Charged to/from Other Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to/from Other Accounts	$ 3	$ (18)	$ 10
Accrued expenses [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to/from Other Accounts	3	(18)	7
Other liabilities [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to/from Other Accounts			$ 3