Inventory and Vehicle Floorplan Payable (Components Of Vehicle Floorplan Payable) (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Floorplan Payable [Line Items] | ||
| Vehicle floorplan payable | $ 4,058.9 | $ 3,828.3 |
| Trade | ||
| Floorplan Payable [Line Items] | ||
| Vehicle floorplan payable | 2,254.1 | 2,200.6 |
| Non-Trade | ||
| Floorplan Payable [Line Items] | ||
| Vehicle floorplan payable | $ 1,804.8 | $ 1,627.7 |