Schedule II - Valuation and Qualifying 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]
Balance at Beginning of Period	$ 329	$ 213	$ 241
Charged to Costs and Expenses		23	1
Charged to Other Accounts		140	9
Deductions	212	47	38
Balance at End of Period	117	329	213
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	329	213	241
Charged to Costs and Expenses		23	1
Charged to Other Accounts		140	9
Deductions	212	47	38
Balance at End of Period	$ 117	$ 329	$ 213