Net Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net Earnings Per Share - Basic [Abstract]
Net earnings available to common shareholders	$ 63.1	$ 79.6	$ 144.3	$ 188.0
Weighted-average common shares outstanding - basic (in shares)	79.5	81.7	79.9	81.9
Net earnings per share - basic (in dollars per share)	$ 0.79	$ 0.97	$ 1.81	$ 2.30
Net Earnings Per Share - Diluted [Abstract]
Net earnings available to common shareholders	$ 63.1	$ 79.6	$ 144.3	$ 188.0
Weighted-average common shares outstanding - basic (in shares)	79.5	81.7	79.9	81.9
Effect of dilutive securities - stock options (in shares)	0.3	0.4	0.3	0.9
Effect of other share-based awards (in shares)	0.2	0.3	0.4	0.5
Weighted-average common shares outstanding - diluted (in shares)	80.0	82.4	80.6	83.3
Net earnings per share - diluted (in dollars per share)	$ 0.79	$ 0.97	$ 1.79	$ 2.26
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)	4.2	3.9	4.2	2.5