Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents		$ 69.2	$ 64.8
Receivables, net		1,111.0	1,032.9
Inventory		3,365.6	3,520.1
Other current assets		251.7	97.0
Total Current Assets		4,797.5	4,714.8
PROPERTY AND EQUIPMENT, NET		2,962.7	2,843.2
GOODWILL	[1]	1,515.0	1,511.3
OTHER INTANGIBLE ASSETS, NET		586.8	598.2
OTHER ASSETS		409.5	392.5
Total Assets		10,271.5	10,060.0
CURRENT LIABILITIES:
Vehicle floorplan payable		3,806.9	3,849.2
Accounts payable		309.8	303.7
Commercial paper		330.0	942.0
Current maturities of long-term debt		414.5	167.5
Other current liabilities		774.5	566.8
Total Current Liabilities		5,635.7	5,829.2
LONG-TERM DEBT, NET OF CURRENT MATURITIES		1,959.2	1,611.1
DEFERRED INCOME TAXES		71.9	91.5
OTHER LIABILITIES		235.4	217.9
COMMITMENTS AND CONTINGENCIES (Note 8)
SHAREHOLDERS' EQUITY:
Preferred stock, par value $0.01 per share; 5,000,000 shares authorized; none issued		0.0	0.0
Common stock, par value $0.01 per share; 1,500,000,000 shares authorized; 102,562,149 shares issued at December 31, 2017, and 120,562,149 shares issued at December 31, 2016, including shares held in treasury		1.0	1.2
Additional paid-in capital		4.0	18.2
Retained earnings		2,832.2	3,133.3
Treasury stock, at cost; 11,002,298 and 19,909,940 shares held, respectively		(467.9)	(842.4)
Total Shareholders' Equity		2,369.3	2,310.3
Total Liabilities and Shareholders' Equity		10,271.5	10,060.0
Trade [Member]
CURRENT LIABILITIES:
Vehicle floorplan payable		2,179.1	2,308.8
Non-Trade [Member]
CURRENT LIABILITIES:
Vehicle floorplan payable		$ 1,627.8	$ 1,540.4

[1] Net of accumulated impairment losses of $1.47 billion 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 associated with our Domestic reporting unit, both of which were recorded during the year ended December 31, 2008.