Financial Instruments (Foreign Exchange Risk and Its Classification on Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Designated derivative Instruments
Asset position
Asset position	$ 2.4	$ 4.4
Liability position
Liability position	1.8	1.4
Undesignated derivative instruments
Asset position
Asset position	17.0	18.0
Potential effect of rights to offset, asset position	(3.7)	(1.7)
Net derivative, asset position	13.3	16.3
Liability position
Liability position	8.8	8.3
Potential effect of rights to offset, liability position	(3.7)	(1.7)
Net derivative, liability position	5.1	6.6
Foreign exchange contracts | Prepaid expenses and other current assets | Designated derivative Instruments
Asset position
Asset position	0.0	4.3
Foreign exchange contracts | Prepaid expenses and other current assets | Undesignated derivative instruments
Asset position
Asset position	14.6	13.6
Foreign exchange contracts | Accounts payable and accrued expenses | Designated derivative Instruments
Liability position
Liability position	0.0	0.1
Foreign exchange contracts | Accounts payable and accrued expenses | Undesignated derivative instruments
Liability position
Liability position	7.0	6.9
Interest rate contracts | Long term borrowings | Designated derivative Instruments
Asset position
Asset position	2.4	0.1
Liability position
Liability position	$ 1.8	$ 1.3