Segment Information (Summary Of Segments Information) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting [Abstract]
Operating Expenses	$ 72		$ 79
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	12,176		12,176		$ 13,815
Revenues	760	$ 2,337	2,513	$ 4,257
Adjusted EBITDA	(382)	175	$ (469)	174
Document Fiscal Year Focus			2020
Non-vehicle related depreciation and amortization	71	66	$ 140	133
Interest expense	51	48	99	90
Early extinguishment of debt	(3)	0	(7)	0
Non-operational charges related to shareholder activist activity			4	0
Transaction-related costs, net	1	1	3	6
Restructuring and other related charges	28	23	72	44
COVID-19 Charges	73		80	0
Income (loss) before income taxes	(609)	81	(874)	(55)
Equity Method Investment, Realized Gain (Loss) on Disposal	0	(44)	0	(44)
Operating Expenses	72		79
Selling, general and administrative	132	313	383	597
Unusual or Infrequent Item, or Both, Net (Gain) Loss	28		33
Operating Leases, Rent Expense, Minimum Rentals	30		30
Supplies Expense	15		17
Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Selling, general and administrative	1		1
Americas [Member]
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	9,900		9,900		10,500
Revenues	565	1,627	1,822	2,954
Adjusted EBITDA	(233)	152	(263)	187
International [Member]
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	2,300		2,300		$ 3,300
Revenues	195	710	691	1,303
Adjusted EBITDA	(140)	39	(180)	18
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	(9)	(16)	(26)	(31)
Americas [Member]
Segment Reporting Information [Line Items]
Revenues	$ 565	$ 1,627	$ 1,822	$ 2,954