Stockholders' Equity (Narrative) (Detail) - USD ($) shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stockholders Equity [Line Items]
Currency translation adjustments (net of tax of $(1), $9, $(6) and $29, respectively)	$ (8,000,000)	$ 32,000,000	$ (61,000,000)	$ 105,000,000
Proceeds from Issuance of Preferred Stock, Preference Stock, and Warrants			$ 100
Document Period End Date			Sep. 30, 2018
Document Fiscal Year Focus			2018
Other Comprehensive Income Unrealized Gain Loss On Cash Flow Hedges Arising During Period Net Of Tax			$ 9,000,000	(2,000,000)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			(1,000,000)	2,000,000
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			8,000,000	$ 0
Stock Repurchase Program, Authorized Amount	1,700,000,000		$ 1,700,000,000
Stock Repurchased During Period, Shares			3.5	4.2
Stock Repurchased During Period, Value			$ 129,000,000	$ 127,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	222,000,000		222,000,000
Selling, General and Administrative Expenses [Member]
Stockholders Equity [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax				6,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	2,000,000	2,000,000	6,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	$ 2,000,000	$ 1,000,000	$ 4,000,000	$ 4,000,000