Hedging Activities, Derivative Instruments and Credit Risk, Derivative Instruments not Designated as Accounting Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative instruments not designated as accounting hedges [Abstract]
Total foreign currency transaction (losses) gains, net	$ (9.3)	$ 5.9	$ (1.1)
Gain on Cross Currency Interest Rate Swaps not Designated as Hedges [Member]
Derivative instruments not designated as accounting hedges [Abstract]
Total foreign currency transaction (losses) gains, net	0.0	0.0	8.0
Foreign Currency Forward Contracts (Losses) Gains [Member]
Derivative instruments not designated as accounting hedges [Abstract]
Total foreign currency transaction (losses) gains, net	$ (7.0)	$ 19.2	$ (0.5)