Stockholders' Equity (Components Of Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity [Abstract]
Net income (loss)	$ 26	$ 3	$ (61)	$ (104)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Document Fiscal Year Focus			2018
Currency translation adjustments (net of tax of $(10), $17, $(5) and $20, respectively)	(54)	48	$ (53)	73
Net unrealized gain (loss) on available-for-sale securities (net of tax of $0 in each period)	0	1	0	1
Net unrealized gain (loss) on cash flow hedges (net of tax of $(1), $1, $(3) and $1, respectively)	2	(2)	8	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	2	1	3	3
Other comprehensive income (loss)			(42)	76
Total comprehensive income (loss)	(24)	51	$ (103)	(28)
Document Period End Date			Jun. 30, 2018
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			$ 0	1
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(10)	17	(5)	20
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	0	0	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(1)	1	(3)	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	0	0	(1)	(1)
Corporate Interest Expense [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax		1		2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax		0		1
Selling, General and Administrative Expenses [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	2	2	4	4
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	1	2	2	3
Including Beginning Balance Adjustment due to Cumulative Effect of Accounting Change [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	$ (50)	$ 48	$ (42)	$ 76