Property And Equipment, Net (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property And Equipment, Net [Abstract]
Depreciation expense	$ 258.4	$ 268.1	$ 296.5
Non-cash capital expenditures	$ 12.4	$ 7.0