Property, Plant and Equipment-Net (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment-Net
Gross property plant and equipment	$ 6,343.2	$ 6,657.6
Less: Accumulated depreciation, depletion and amortization	2,241.5	2,757.1
Net property, plant and equipment	4,101.7	3,900.5
Land
Property, Plant and Equipment-Net
Gross property plant and equipment	37.9	60.2
Mineral Properties
Property, Plant and Equipment-Net
Gross property plant and equipment		202.6
Machinery and equipment
Property, Plant and Equipment-Net
Gross property plant and equipment	5,046.8	5,388.6
Changes in plant turnaround activity
Balance at the beginning of the period	82.1	54.8	66.8
Additions	78.6	56.6	16.2
Depreciation	(40.8)	(29.6)	(27.9)
Effect of exchange rate changes	(0.1)	0.3	(0.3)
Balance at the end of the period	119.8	82.1	54.8
Buildings and improvements
Property, Plant and Equipment-Net
Gross property plant and equipment	159.4	537.1
Construction in progress
Property, Plant and Equipment-Net
Gross property plant and equipment	$ 1,099.1	$ 469.1