Reconciliation of Adjusted EBITDA to Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Information [Abstract]
Adjusted EBITDA			$ 802	[1]	$ 605	[1]	$ 398	[1]
Less: Non-vehicle related depreciation and amortization			125		95		90
Interest expense related to corporate debt, net	7	7	268		219		170
Early extinguishment of debt			75				52
Transaction-related costs			34		255		14
Income before income taxes			$ 300		$ 36		$ 72

[1] Adjusted EBITDA includes restructuring costs of $38 million, $5 million and $11 million for the years ended December 31, 2012, 2011 and 2010, respectively.