Net Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net Earnings Per Share - Basic [Abstract]
Net earnings available to common shareholders	$ 23.9	$ 40.2
Weighted-average common shares outstanding - basic (in shares)	77.1	80.2
Net earnings per share - basic (in dollars per share)	$ 0.31	$ 0.50
Net Earnings Per Share - Diluted [Abstract]
Effect of dilutive securities - stock options (in shares)	0.6	0.4
Effect of other share-based awards (in shares)	0.5	0.3
Weighted-average common shares outstanding - diluted (in shares)	78.2	80.9
Net earnings per share - diluted (in dollars per share)	$ 0.31	$ 0.50
Share-based awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the calculation of Net Earnings Per Share (in shares)	3.4	4.1