Income Taxes (Unrecognized Tax Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefit — Beginning balance	$ 33.4	$ 25.1	$ 31.9
Gross Increases — Tax Positions in Prior Period	10.7	1.6	2.1
Gross Decreases — Tax Positions in Prior Period	(3.8)	(0.4)	(0.6)
Gross Increases — Tax Positions in Current Period	1.0	11.1	2.6
Dispositions	0.0	0.0	(2.2)
Settlements	0.0	(0.4)	0.0
Lapse of Statute of Limitations	(2.7)	(3.3)	(5.3)
Impact of U.S. Tax Reform Tax Rate Reduction	(10.1)	0.0	0.0
Foreign Currency Translation	0.1	(0.3)	(3.4)
Unrecognized Tax Benefit — Ending Balance	$ 28.6	$ 33.4	$ 25.1