SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for loss on receivables:
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 118	$ 101	$ 137
Acquired/(Disposed) Balances	0	0	(39)
Charged (Credited) to Costs and Expenses	20	39	61
Charged to Other Accounts	(10)	19	(7)
Deductions or Write-offs	(32)	(41)	(51)
Balance at End of Period	96	118	101
Deferred tax asset valuation allowance:
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	49	42	48
Acquired/(Disposed) Balances	0	0	0
Charged (Credited) to Costs and Expenses	0	(7)	6
Charged to Other Accounts	0	0	0
Deductions or Write-offs	0	0	0
Balance at End of Period	$ 49	$ 49	$ 42