Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 117	$ 329	$ 213
Charged to Costs and Expenses			23
Charged to Other Accounts			140
Deductions	21	212	47
Balance at End of Period	96	117	329
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	117	329	213
Charged to Costs and Expenses			23
Charged to Other Accounts			140
Deductions	21	212	47
Balance at End of Period	$ 96	$ 117	$ 329