Stockholders' Equity (Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ (316)	$ 292	$ (155)	$ 656
Other comprehensive income (loss) before reclassifications			5	(71)
Amounts reclassified from accumulated other comprehensive income (loss)			21	5
Other comprehensive income (loss)	2	33	26	(66)
Ending Balance	92	(153)	92	(153)
Foreign exchange contracts | Derivatives designated as hedging instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Derivatives used in net investment hedge, net of tax	37		37
Currency Translation Adjustments (a)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			40	9
Other comprehensive income (loss) before reclassifications			(10)	(44)
Amounts reclassified from accumulated other comprehensive income (loss)			11	0
Other comprehensive income (loss)			1	(44)
Ending Balance	41	(35)	41	(35)
Net Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(51)	(20)
Other comprehensive income (loss) before reclassifications			14	(28)
Amounts reclassified from accumulated other comprehensive income (loss)			7	2
Other comprehensive income (loss)			21	(26)
Ending Balance	(30)	(46)	(30)	(46)
Net Unrealized Gains (Losses) on Cash Flow Hedges | Corporate Interest Expense
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated other comprehensive income (loss)	3	1	6	1
Reclassification before tax	4	2	8	1
Net Unrealized Gains (Losses) on Cash Flow Hedges | Vehicle Interest Net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated other comprehensive income (loss)	1		1
Reclassification before tax	1		2
Minimum Pension Liability Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(176)	(146)
Other comprehensive income (loss) before reclassifications			1	1
Amounts reclassified from accumulated other comprehensive income (loss)			3	3
Other comprehensive income (loss)			4	4
Ending Balance	(172)	(142)	(172)	(142)
Minimum Pension Liability Adjustment | Selling, General and Administrative Expenses
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated other comprehensive income (loss)	1	2	3	3
Reclassification before tax	2	2	5	4
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(163)	(256)	(187)	(157)
Other comprehensive income (loss)	2	33	26	(66)
Ending Balance	$ (161)	$ (223)	$ (161)	$ (223)