Write-downs, Reserves, and Project Opening Costs, net of Recoveries (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Write-downs and reserves, net of recoveries:
Remediation costs	$ 12.1	$ 2.4
Divestitures and abandonments	1.8	6.2
Efficiency projects	0	6.1
Other	5.1	(0.2)
Total write-downs and reserves, net of recoveries	19.0	14.5
Project opening costs	1.7	1.7
Total write-downs, reserves, and project opening costs, net of recoveries	$ 20.7	$ 16.2