Components of Company's Vehicles (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure Components Of Companys Vehicles [Abstract]
Rental vehicles	$ 9,210	$ 13,461
Less: Accumulated depreciation	(1,337)	(1,621)
Rental Vehicles Net, Total	7,873	11,840
Vehicles held for sale	280	337
Vehicles, net	$ 8,153	$ 12,177