Unaudited Condensed Consolidated Income Statements - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
TOTAL REVENUE		$ 4,667.0	$ 4,981.8
TOTAL COST OF SALES (excluding depreciation shown below)		3,853.8	4,132.6
TOTAL GROSS PROFIT		813.2	849.2
Selling, general, and administrative expenses		600.7	623.0
Depreciation and amortization		48.1	44.1
Goodwill impairment		318.3	0.0
Franchise rights impairment		57.5	0.0
Other (income) expense, net		7.9	(8.7)
OPERATING INCOME (LOSS)		(219.3)	190.8
Non-operating income (expense) items:
Floorplan interest expense		(25.5)	(39.0)
Other interest expense		(23.5)	(27.8)
Interest income		0.1	0.2
Other income (loss), net		(3.0)	1.9
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES		(271.2)	126.1
Income tax provision (benefit)		(39.0)	34.0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS		(232.2)	92.1
Loss from discontinued operations, net of income taxes		(0.1)	(0.1)
NET INCOME (LOSS)		$ (232.3)	$ 92.0
BASIC EARNINGS (LOSS) PER SHARE:
Continuing operations (in dollars per share)	[1]	$ (2.58)	$ 1.02
Discontinued operations (in dollars per share)	[1]	0	0
Net income (loss) (in dollars per share)	[1]	$ (2.58)	$ 1.02
Weighted average common shares outstanding (in shares)		90.0	90.5
DILUTED EARNINGS (LOSS) PER SHARE:
Continuing operations (in dollars per share)	[1]	$ (2.58)	$ 1.02
Discontinued operations (in dollars per share)	[1]	0	0
Net income (loss) (in dollars per share)	[1]	$ (2.58)	$ 1.01
Weighted average common shares outstanding (in shares)		90.0	90.7
COMMON SHARES OUTSTANDING, net of treasury stock, at period end (in shares)		87.2	89.2
New Vehicle [Member]
TOTAL REVENUE		$ 2,281.9	$ 2,496.7
TOTAL COST OF SALES (excluding depreciation shown below)		2,185.5	2,374.8
TOTAL GROSS PROFIT		96.4	121.9
Used Vehicle [Member]
TOTAL REVENUE		1,248.7	1,339.6
TOTAL COST OF SALES (excluding depreciation shown below)		1,157.7	1,249.1
TOTAL GROSS PROFIT		91.0	90.5
Parts and Service [Member]
TOTAL REVENUE		876.3	876.7
TOTAL COST OF SALES (excluding depreciation shown below)		487.5	477.8
TOTAL GROSS PROFIT		388.8	398.9
Finance and Insurance, Net [Member]
TOTAL REVENUE		235.8	236.5
TOTAL GROSS PROFIT		235.8	236.5
Product and Service, Other [Member]
TOTAL REVENUE		24.3	32.3
TOTAL COST OF SALES (excluding depreciation shown below)		23.1	30.9
TOTAL GROSS PROFIT		$ 1.2	$ 1.4

[1] Earnings per share amounts are calculated discretely and therefore may not add up to the total due to rounding.