Property, Plant and Equipment-Net (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Property, Plant and Equipment-Net
Gross property plant and equipment	$ 8,036.8		$ 6,343.2
Less: Accumulated depreciation, depletion and amortization	2,511.0		2,241.5
Net property, plant and equipment	5,525.8		4,101.7		3,900.5
Construction in progress expenditures incurred but not yet paid	279.0		228.9
Accrued expansion project costs	244.3		203.6
Land
Property, Plant and Equipment-Net
Gross property plant and equipment	48.4		37.9
Machinery and equipment
Property, Plant and Equipment-Net
Gross property plant and equipment	5,268.7		5,046.8
Changes in plant turnaround activity
Balance at the beginning of the period	119.8		82.1		54.8
Additions	88.3		78.6		56.6
Depreciation	(53.9)		(40.8)		(29.6)
Effect of exchange rate changes	(1.0)		(0.1)		0.3
Balance at the end of the period	153.2		119.8		82.1
Buildings and improvements
Property, Plant and Equipment-Net
Gross property plant and equipment	160.7		159.4
Construction in Progress
Property, Plant and Equipment-Net
Gross property plant and equipment	2,559.0	[1]	1,099.1	[1]
Capacity expansion project
Property, Plant and Equipment-Net
Gross property plant and equipment	$ 2,000.0		$ 700.0

[1] As of December 31, 2014 and 2013, we had construction in progress that was accrued but unpaid of $279.0 million and $228.9 million, respectively. These amounts included accruals related to our capacity expansion projects of $244.3 million and $203.6 million as of December 31, 2014 and 2013, respectively.