Vehicle Financing (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Vehicle Financing
Maturity period of floor plan arrangements outside the U.S. if not payable on demand	90 days
Weighted average interest rate on floor plan borrowings (as a percent)	2.10%	1.90%	2.60%