Intangible Assets - Narrative (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Goodwill [Line Items]
Goodwill	$ 2,820,100,000	$ 2,435,700,000
Retail automotive dealership
Goodwill [Line Items]
Goodwill	2,242,100,000
Retail commercial truck dealership
Goodwill [Line Items]
Goodwill	500,300,000
Other
Goodwill [Line Items]
Goodwill	77,700,000
Non-Automotive Investments
Goodwill [Line Items]
Goodwill	$ 0