Basic and Diluted Net Loss Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net loss
Net loss	$ (102.2)	$ (72.4)	$ (188.6)	$ (117.4)
Net loss			$ (188.6)	$ (117.4)
Basic and diluted net loss per share:
Basic	$ (1.19)	$ (0.86)	$ (2.20)	$ (1.39)
Diluted	$ (1.19)	$ (0.86)	$ (2.20)	$ (1.39)
Weighted average number of shares used in per share calculations:
Basic shares	85.9	84.4	85.6	84.4
Diluted shares	85.9	84.4	85.6	84.4