Share-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-Based Compensation [Abstract]
Fair value of share-based compensation awards, granted	$ 1.8	$ 2.5	$ 23.8	$ 22.8
Unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards outstanding	$ 46.8		$ 46.8
Weighted average recognition period for unrecognized compensation expense, in years			2 years