Derivatives Derivative Net Gain (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative, gain (loss) on derivative, net	$ 6.3	$ (16.5)	$ 3.5
Commodity Contract [Member]
Derivative [Line Items]
Derivative, gain (loss) on derivative, net	6.6	(16.5)	3.5
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, gain (loss) on derivative, net	$ (0.3)	$ 0.0	$ 0.0