Plant Turnaround Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net capitalized turnaround costs:
Balance at the beginning of the period	$ 54.8	$ 66.8
Additions	5.6	1.2
Depreciation	(8.0)	(7.3)
Effect of exchange rate changes	0.9	0.4
Balance at the end of the period	$ 53.3	$ 61.1