Share-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-Based Compensation [Abstract]
Fair value of share-based compensation awards, granted	$ 0.6	$ 1.0	$ 24.4	$ 23.8
Unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards outstanding	$ 42.7		$ 42.7
Weighted average recognition period for unrecognized compensation expense, in years			1 year 9 months 18 days