Intangible Assets - Narrative (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Goodwill [Line Items]
Goodwill	$ 2,316,600,000	$ 2,234,900,000
Retail automotive dealership
Goodwill [Line Items]
Goodwill	1,750,800,000
Retail commercial truck dealership
Goodwill [Line Items]
Goodwill	492,300,000
Other
Goodwill [Line Items]
Goodwill	73,500,000
Non-Automotive Investments
Goodwill [Line Items]
Goodwill	$ 0