Intangible Assets - Narrative (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Goodwill [Line Items]
Goodwill	$ 2,356,400,000	$ 2,234,900,000
Retail automotive dealership
Goodwill [Line Items]
Goodwill	1,776,500,000
Retail commercial truck dealership
Goodwill [Line Items]
Goodwill	504,700,000
Other
Goodwill [Line Items]
Goodwill	75,200,000
Non-Automotive Investments
Goodwill [Line Items]
Goodwill	$ 0