Summary of Significant Accounting Policies (Adjustments in Consolidated Statement of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net income including noncontrolling interest	$ 85.2	$ 76.9	$ 64.5
Deferred income taxes	8.7	21.6	(55.6)
Inventory impairment charges			0
Increase in inventories	(148.8)	(170.8)	236.0
Net cash flows of operating activities	97.3	98.9	546.3
As Originally Reported [Member]
Net income including noncontrolling interest			116.6
Deferred income taxes			(29.9)
Inventory impairment charges			(34.6)
Increase in inventories			192.8
Net cash flows of operating activities			546.3
Adjustment [Member]
Net income including noncontrolling interest			(52.1)
Deferred income taxes			(25.7)
Inventory impairment charges			34.6
Increase in inventories			43.2
Net cash flows of operating activities			$ 0