Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) - 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
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 55.8	$ 59.7	$ 106.8	$ 108.4
Average basic shares outstanding	58.0	58.9	58.0	58.7
Effect of dilutive stock options	0.8	1.0	0.8	1.0
Average diluted shares outstanding	58.8	59.8	58.8	59.7
Earnings per share - basic:
Net income attributable to common shareholders	$ 0.96	$ 1.01	$ 1.84	$ 1.85
Earnings per share - diluted:
Net income attributable to common shareholders	$ 0.95	$ 1.00	$ 1.82	$ 1.82