Earnings (Loss) Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.3	0.4
Computations of basic and diluted earnings per share for income from continuing operations
Net income	$ 19.9	$ 8.0
Add: Loss from discontinued operations	0	7.8
Income from continuing operations	$ 19.9	$ 15.8
Weighted-average shares outstanding - basic	49.0	50.3
Effect of diluted securities attributable to stock-based payments	0.9	0.7
Weighted-average shares outstanding - diluted	49.9	51.0
Earnings per share:
Income from continuing operations, Basic	$ 0.41	$ 0.32
Loss from discontinued operations, Basic	$ 0.00	$ (0.16)
Net income (loss), Basic	$ 0.41	$ 0.16
Income from continuing operations, Diluted	$ 0.40	$ 0.31
Loss from discontinued operations, Diluted	$ 0.00	$ (0.15)
Net income (loss), Diluted	$ 0.40	$ 0.16