Stockholders' Equity (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders Equity [Line Items]
Currency translation adjustments (net of tax of $(6) and $5, respectively)	$ 1	$ 1
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Other Comprehensive Income Unrealized Gain Loss On Cash Flow Hedges Arising During Period Net Of Tax	$ (7)	6
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(1)	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(8)	$ 6
Stock Repurchase Program, Authorized Amount	1,700
Stock Repurchase Program, Remaining Authorized Repurchase Amount	150
Selling, General and Administrative Expenses [Member]
Stockholders Equity [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	2
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	$ 1