Stockholders' Equity (Narrative) (Detail) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Aug. 01, 2018
Stockholders Equity [Line Items]
Currency translation adjustments (net of tax of $(10), $17, $(5) and $20, respectively)	$ (54,000,000)	$ 48,000,000	$ (53,000,000)	$ 73,000,000
Proceeds from Issuance of Preferred Stock, Preference Stock, and Warrants			$ 100
Document Period End Date			Jun. 30, 2018
Document Fiscal Year Focus			2018
Other Comprehensive Income Unrealized Gain Loss On Cash Flow Hedges Arising During Period Net Of Tax			$ 8,000,000	(2,000,000)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			0	1,000,000
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			8,000,000	$ (1,000,000)
Stock Repurchase Program, Authorized Amount	1,500,000,000		$ 1,500,000,000
Stock Repurchased During Period, Shares			1.6	3.4
Stock Repurchased During Period, Value			$ 67,000,000	$ 100,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	33,000,000		33,000,000
Selling, General and Administrative Expenses [Member]
Stockholders Equity [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	2,000,000	2,000,000	4,000,000	4,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	$ 1,000,000	$ 2,000,000	$ 2,000,000	$ 3,000,000
Subsequent Event [Member]
Stockholders Equity [Line Items]
Stock Repurchase Program, Authorized Amount					$ 250,000,000