Components Of Vehicle Depreciation And Lease Charges (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Vehicle Depreciation and Lease Charges, Net [Line Items]
Depreciation expense	$ 1,890	$ 1,974	$ 1,947
Lease charges	255	253	222
(Gain) loss on sale of vehicles, net	(82)	(48)	52
Vehicle depreciation and lease charges, net	2,063	2,179	2,221
Accounts Payable, Other, Current	418	472	346
Receivables due from former subsidiaries	$ 576	$ 622	$ 545