INVENTORIES AND FLOOR PLAN NOTES PAYABLE - Schedule of Debt (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Inventory Disclosure [Abstract] | ||
| Floor plan notes payable | $ 1,986.2 | $ 1,992.6 |
| Floor plan notes payable: non-trade | 4,401.2 | 3,016.3 |
| Total floor plan debt | $ 6,387.4 | $ 5,008.9 |