Vehicle Rental Activities (Components Of Vehicle Depreciation And Lease Charges) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Vehicle Rental Activities [Abstract]
Depreciation expense	$ 540	$ 547	$ 1,536	$ 1,500
Lease charges	72	67	192	164
(Gain) loss on sale of vehicles, net	(25)	2	(35)	53
Vehicle depreciation and lease charges, net	$ 587	$ 616	$ 1,693	$ 1,717