Financial Instruments (Summary of Derivative Instruments) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Notional amount	$ 1,495.1	$ 1,309.1
Maximum duration (in months)	3 months	3 months
Fair value - net asset	$ 10.9	$ 6.7
Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Notional amount		78.7
Maximum duration (in months)	6 months
Fair value - net asset		4.2
Fair Value Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount	$ 1,000.0	1,000.0
Fair value - net asset	$ 2.4	$ (1.2)