Vehicle Rental Activities (Components Of Vehicle Depreciation And Lease Charges) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Vehicle Depreciation and Lease Charges, Net [Line Items]
Depreciation expense	$ 406	$ 370	$ 1,100	$ 1,034
Lease charges	38	10	95	30
Gain on sales of vehicles, net and cost of vehicle disposition	(8)	(76)	(107)	(224)
Vehicle depreciation and lease charges, net	$ 436	$ 304	$ 1,088	$ 840