Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income (loss) from continuing operations	$ 65.6	$ (24.6)	$ 107.6	$ (78.6)
Loss from discontinued operations	0.0	(1.9)	0.0	(1.9)
Net Income (loss)	$ 65.6	$ (26.5)	$ 107.6	$ (80.5)
Weighted average common shares outstanding	143.7	142.6	143.3	142.3
Dilutive effect of stock warrants	0.2		0.2
Dilutive effect of employee stock plans	1.5		1.7
Dilutive potential common shares	1.7		1.9
Adjusted weighted average shares	145.4	142.6	145.2	142.3
Net income (loss) per share of common stock (basic):
Income (loss) from continuing operations	$ 0.46	$ (0.17)	$ 0.75	$ (0.55)
Loss from discontinued operations	0.00	(0.02)	0.00	(0.02)
Net income (loss) per share - basic	0.46	(0.19)	0.75	(0.57)
Net income (loss) per share of common stock (diluted):
Income (loss) from continuing operations	0.45	(0.17)	0.74	(0.55)
Loss from discontinued operations	0.00	(0.02)	0.00	(0.02)
Net income (loss) per share - diluted	$ 0.45	$ (0.19)	$ 0.74	$ (0.57)