Unaudited Condensed Consolidated Statements Of Operations - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
TOTAL REVENUE		$ 6,666.0	$ 6,379.5	$ 20,288.0	$ 19,261.7
TOTAL COST OF SALES (excluding depreciation shown below)		5,353.2	5,107.6	16,304.6	15,630.7
TOTAL GROSS PROFIT		1,312.8	1,271.9	3,983.4	3,631.0
Selling, general, and administrative expenses		763.2	723.7	2,259.4	2,120.5
Depreciation and amortization		50.1	47.6	148.9	143.4
Other income, net		(23.0)	(2.7)	(24.5)	(3.3)
OPERATING INCOME		522.5	503.3	1,599.6	1,370.4
Non-operating income (expense) items:
Floorplan interest expense		(10.7)	(4.9)	(21.7)	(20.9)
Other interest expense		(33.7)	(24.1)	(97.4)	(66.2)
Other income (loss), net		(4.6)	(0.8)	(24.7)	19.1
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES		473.5	473.5	1,455.8	1,302.4
Income tax provision		120.8	111.8	364.5	316.3
NET INCOME FROM CONTINUING OPERATIONS		352.7	361.7	1,091.3	986.1
Loss from discontinued operations, net of income taxes		(0.1)	0.0	(0.3)	(0.2)
NET INCOME		$ 352.6	$ 361.7	$ 1,091.0	$ 985.9
BASIC EARNINGS (LOSS) PER SHARE:
Continuing operations (in dollars per share)	[1]	$ 6.35	$ 5.17	$ 18.65	$ 12.76
Discontinued operations (in dollars per share)	[1]	0	0	(0.01)	0
Net income (in dollars per share)	[1]	$ 6.35	$ 5.17	$ 18.65	$ 12.75
Weighted average common shares outstanding (in shares)		55.5	69.9	58.5	77.3
DILUTED EARNINGS (LOSS) PER SHARE:
Continuing operations (in dollars per share)	[1]	$ 6.31	$ 5.12	$ 18.53	$ 12.63
Discontinued operations (in dollars per share)	[1]	0	0	(0.01)	0
Net income (in dollars per share)	[1]	$ 6.31	$ 5.12	$ 18.52	$ 12.62
Weighted average common shares outstanding (in shares)		55.9	70.7	58.9	78.1
COMMON SHARES OUTSTANDING, net of treasury stock, at period end (in shares)		52.3	65.5	52.3	65.5
New vehicle
TOTAL REVENUE		$ 2,863.9	$ 2,753.8	$ 8,606.9	$ 9,164.4
TOTAL COST OF SALES (excluding depreciation shown below)		2,534.2	2,434.2	7,578.7	8,334.3
TOTAL GROSS PROFIT		329.7	319.6	1,028.2	830.1
Used vehicle
TOTAL REVENUE		2,401.7	2,323.2	7,494.5	6,295.2
TOTAL COST OF SALES (excluding depreciation shown below)		2,259.7	2,146.2	7,059.4	5,775.3
TOTAL GROSS PROFIT		142.0	177.0	435.1	519.9
Parts and service
TOTAL REVENUE		1,032.1	943.7	3,072.3	2,745.5
TOTAL COST OF SALES (excluding depreciation shown below)		553.5	518.9	1,650.9	1,499.2
TOTAL GROSS PROFIT		478.6	424.8	1,421.4	1,246.3
Finance and insurance, net
TOTAL REVENUE		360.7	348.9	1,092.2	1,030.9
TOTAL GROSS PROFIT		360.7	348.9	1,092.2	1,030.9
Other
TOTAL REVENUE		7.6	9.9	22.1	25.7
TOTAL COST OF SALES (excluding depreciation shown below)		5.8	8.3	15.6	21.9
TOTAL GROSS PROFIT		$ 1.8	$ 1.6	$ 6.5	$ 3.8

[1] (1) EPS amounts are calculated discretely and, therefore, may not add up to the total due to rounding.