Valuation And Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 34	$ 50	$ 40
Expensed	24	17	15
Other Adjustments	(3)	(3)	10
Deductions	(21)	(30)	(15)
Balance at End of Period	34	34	50
Tax Valuation Allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	319	347	298
Expensed	20	(9)	27
Other Adjustments	12	(13)	22
Deductions	0	(6)	0
Balance at End of Period	$ 351	$ 319	$ 347