Inventories (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Components of inventories
Finished goods	$ 290.1	$ 222.3
Work in process	14.8	13.2
Raw materials and repair parts	167.4	156.3
Gross inventories	472.3	391.8
Excess of current cost over last-in, first-out cost and other items	(73.9)	(73.9)
Total inventories, net	$ 398.4	$ 317.9