Components Of Vehicle Depreciation And Lease Charges (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Vehicle Depreciation and Lease Charges, Net [Line Items]
Depreciation expense	$ 1,877	$ 1,837	$ 1,840
Lease charges	180	156	163
Gain on sale of vehicles, net	(10)	(60)	(7)
Vehicle depreciation and lease charges, net	2,047	1,933	1,996
Accounts Payable, Other, Current	321	269	222
Receivables due from former subsidiaries	$ 520	$ 433	$ 352