Unaudited Condensed Consolidated Income Statements (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
TOTAL REVENUE	$ 4,788.5	$ 4,426.5	$ 9,152.0	$ 8,522.9
TOTAL COST OF SALES (excluding depreciation shown below)	4,043.6	3,730.4	7,699.7	7,162.8
TOTAL GROSS PROFIT	744.9	696.1	1,452.3	1,360.1
Selling, general, and administrative expenses	524.6	494.1	1,025.3	967.4
Depreciation and amortization	26.2	23.3	51.8	46.0
Other income, net	(3.7)	(2.2)	(11.7)	(3.6)
OPERATING INCOME	197.8	180.9	386.9	350.3
Non-operating income (expense) items:
Floorplan interest expense	(13.3)	(13.6)	(26.5)	(26.5)
Other interest expense	(21.3)	(22.0)	(42.9)	(44.3)
Interest income	0.1	0	0.1	0.1
Other income, net	0.9	1.3	2.4	2.9
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	164.2	146.6	320.0	282.5
Income tax provision	63.5	56.5	123.8	109.2
NET INCOME FROM CONTINUING OPERATIONS	100.7	90.1	196.2	173.3
Loss from discontinued operations, net of income taxes	(0.3)	(0.2)	(0.7)	(0.4)
NET INCOME	100.4	89.9	195.5	172.9
BASIC EARNINGS (LOSS) PER SHARE:
Continuing operations	$ 0.85	$ 0.74	$ 1.64	$ 1.43
Discontinued operations	$ 0.00	$ 0.00	$ (0.01)	$ 0.00
Net income	$ 0.84	$ 0.74	$ 1.64	$ 1.43
Weighted average common shares outstanding	119.1	121.4	119.3	121.2
DILUTED EARNINGS (LOSS) PER SHARE:
Continuing operations	$ 0.83	$ 0.73	$ 1.62	$ 1.41
Discontinued operations	$ 0.00	$ 0.00	$ (0.01)	$ 0.00
Net income	$ 0.83	$ 0.73	$ 1.61	$ 1.40
Weighted average common shares outstanding	120.8	123.3	121.1	123.2
COMMON SHARES OUTSTANDING, net of treasury stock, at period end	118.5	121.3	118.5	121.3
New Vehicle [Member]
TOTAL REVENUE	2,736.9	2,493.6	5,165.5	4,751.3
TOTAL COST OF SALES (excluding depreciation shown below)	2,575.3	2,344.4	4,858.0	4,460.4
TOTAL GROSS PROFIT	161.6	149.2	307.5	290.9
Used Vehicle [Member]
TOTAL REVENUE	1,082.3	1,056.5	2,132.0	2,066.2
TOTAL COST OF SALES (excluding depreciation shown below)	993.0	972.4	1,948.4	1,896.1
TOTAL GROSS PROFIT	89.3	84.1	183.6	170.1
Parts and Service [Member]
TOTAL REVENUE	704.8	655.9	1,375.8	1,292.5
TOTAL COST OF SALES (excluding depreciation shown below)	404.0	375.7	788.3	740.0
TOTAL GROSS PROFIT	300.8	280.2	587.5	552.5
Finance and Insurance, Net [Member]
TOTAL REVENUE	185.4	173.9	357.8	329.5
TOTAL GROSS PROFIT	185.4	173.9	357.8	329.5
Other Goods and Services [Member]
TOTAL REVENUE	79.1	46.6	120.9	83.4
TOTAL COST OF SALES (excluding depreciation shown below)	71.3	37.9	105.0	66.3
TOTAL GROSS PROFIT	$ 7.8	$ 8.7	$ 15.9	$ 17.1