Stockholders' Equity (Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ (5)	$ 39
Currency Translation Adjustments, Balance			$ (3)	$ 71
Net Unrealized Gains (Losses) on Cash Flow Hedges, Balance	$ (22)	$ 14	(22)	14
Net Unrealized Gains on Available- For-Sale Securities, Balance			0	2
Currency Translation Adjustments, Balance			(132)	(102)
Accumulated Other Comprehensive Income, Balance			(133)	(24)
Currency Translation Adjustments, Current period change	(31)	(8)	(21)	(61)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(4)	0	(25)	8
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(1)	(2)	(5)	(5)
Other comprehensive income (loss)	(34)	(6)	(41)	(48)
Currency Translation Adjustments, Balance	(24)	17	(24)	17
Net Unrealized Gains (Losses) on Cash Flow Hedges, Balance			2	5
Net Unrealized Gains on Available- For-Sale Securities, Balance	0	0	0	0
Currency Translation Adjustments, Balance	(127)	(109)	(127)	(109)
Accumulated Other Comprehensive Income, Balance	(173)	(78)	(173)	(78)
Derivatives used in Net Investment Hedge, Net of Tax	101		101
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent			(21)	(61)
Other Comprehensive Income Unrealized Gain Loss On Cash Flow Hedges Arising During Period Net Of Tax			(23)	9
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax			(25)	8
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax			0	0
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Net of Tax			4	4
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(43)	(51)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			2	3
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax			0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax			0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			2	1
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax			0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax			1	1
Corporate Interest Expense [Member]
Stockholders Equity [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	1	2	4	2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	(1)	(2)	(1)
Selling, General and Administrative Expenses [Member]
Stockholders Equity [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	2	2	6	6
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	$ 1	$ 2	4	4
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						(7)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					(1)	(1)
AOCI Attributable to Parent [Member]
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ (1)	6
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						2
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Stockholders Equity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets						$ 12
Adjustments for New Accounting Pronouncement [Member]
Stockholders Equity [Line Items]
Currency Translation Adjustments, Balance			(3)	78
Net Unrealized Gains on Available- For-Sale Securities, Balance			0	0
Currency Translation Adjustments, Balance			(132)	(114)
Accumulated Other Comprehensive Income, Balance			(132)	(30)
Net Unrealized Gains (Losses) on Cash Flow Hedges, Balance			$ 3	$ 6