Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 69.7		$ 86.6
Receivables, net	698.4		587.4
Inventory	2,396.9		1,809.2
Other current assets	196.1		193.0
Total Current Assets	3,361.1		2,676.2
PROPERTY AND EQUIPMENT, NET	2,095.1		1,950.7
GOODWILL, NET	1,237.4	[1]	1,172.2	[1]
OTHER INTANGIBLE ASSETS, NET	291.3		217.8
OTHER ASSETS	218.1		181.9
Total Assets	7,203.0		6,198.8
CURRENT LIABILITIES:
Vehicle floorplan payable	2,540.2		1,898.8
Accounts payable	235.8		202.4
Current maturities of long-term debt	29.8		12.6
Other current liabilities	395.9		348.8
Total Current Liabilities	3,201.7		2,462.6
LONG-TERM DEBT, NET OF CURRENT MATURITIES	2,066.3		1,634.4
DEFERRED INCOME TAXES	89.4		62.3
OTHER LIABILITIES	157.1		144.9
COMMITMENTS AND CONTINGENCIES (Note 8)
SHAREHOLDERS' EQUITY:
Preferred stock, par value $0.01 per share; 5,000,000 shares authorized; none issued	0		0
Common stock, par value $0.01 per share; 1,500,000,000 shares authorized; 163,562,149 shares issued at December 31, 2012 and 2011, including shares held in treasury	1.6		1.6
Additional paid-in capital	26.6		19.6
Retained earnings	2,963.0		2,646.6
Treasury stock, at cost; 42,705,580 and 27,777,625 shares held, respectively	(1,302.7)		(773.2)
Total Shareholders' Equity	1,688.5		1,894.6
Total Liabilities and Shareholders' Equity	7,203.0		6,198.8
Trade [Member]
CURRENT LIABILITIES:
Vehicle floorplan payable	1,766.3		1,362.3
Non-Trade [Member]
CURRENT LIABILITIES:
Vehicle floorplan payable	$ 773.9		$ 536.5

[1] Net of accumulated impairment losses of $1.47 billion ($1.25 billion after-tax) associated with our single reporting unit (prior to September 30, 2008, our reporting unit structure was comprised of a single reporting unit) and $140.0 million ($119.0 million after-tax) associated with our Domestic reporting unit, both of which were recorded during the year ended December 31, 2008.