Segment Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) segments	Jun. 30, 2020 USD ($) segments
Segment Reporting Information [Line Items]
Number of reportable segments | segments			3	3
Revenues	$ 6,978.4	$ 4,533.0	$ 12,882.2	$ 9,200.0
Segment Income	598.4	259.6	1,001.3	459.8
AN Reportable Segment, Domestic [Member]
Segment Reporting Information [Line Items]
Revenues	2,124.8	1,486.0	3,971.5	2,969.5
Segment Income	169.0	82.1	287.5	136.2
AN Reportable Segment, Import [Member]
Segment Reporting Information [Line Items]
Revenues	2,175.0	1,325.3	3,944.6	2,687.4
Segment Income	203.7	88.3	329.6	154.2
AN Reportable Segment, Premium Luxury [Member]
Segment Reporting Information [Line Items]
Revenues	2,468.5	1,564.8	4,572.0	3,181.6
Segment Income	$ 225.7	$ 89.2	$ 384.2	$ 169.4