Inventory And Vehicle Floorplan Payable (Components Of Vehicle Floorplan Payable) (Details) (USD $) In Millions | Sep. 30, 2011 | Dec. 31, 2010 |
|---|---|---|
| Vehicle floorplan payable | $ 1,511.3 | $ 1,866.4 |
Trade [Member] | ||
| Vehicle floorplan payable | 1,043.2 | 1,379.9 |
Non-Trade [Member] | ||
| Vehicle floorplan payable | $ 468.1 | $ 486.5 |