Accumulated Other Comprehensive Income (Loss) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign Exchange Gains (Losses) From Translation Of Acturial Losses and Prior Service Credit	$ 16.3	$ (23.7)	$ (21.9)