Financial Instruments and Risk Management (Effect of Derivative Instruments on the Consolidated Statements of Comprehensive Earnings Derivatives in Cash Flow Hedging Relationships) (Details) - Cash flow hedging relationships - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 28.1	$ (66.2)	$ (31.0)
Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	28.1	(27.5)	(44.5)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 0.0	$ (38.7)	$ 13.5