Financial Instruments (Effect of Risk-Management Instruments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flow hedges:
Total	$ (14.6)	$ 24.4
Foreign currency-denominated notes
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), net investment hedges	67.4	53.7
Cross-currency interest rate swaps
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), net investment hedges	115.8	38.3
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), cash flow hedges	(69.8)	(30.0)
Forward-starting interest rate swaps
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), cash flow hedges	(369.8)	(11.7)
Designated as Hedging Instrument | Foreign currency-denominated notes
Fair value hedges:
Effect from hedged fixed-rate debt	117.3	39.3
Designated as Hedging Instrument | Interest rate contracts
Fair value hedges:
Effect from interest rate contracts	(117.3)	(39.3)
Cash flow hedges:
Effective portion of losses on interest rate contracts reclassified from accumulated other comprehensive loss	4.0	3.8
Designated as Hedging Instrument | Cross-currency interest rate swaps
Cash flow hedges:
Effective portion of losses on interest rate contracts reclassified from accumulated other comprehensive loss	(12.9)	(28.3)
Not Designated as Hedging Instrument | Foreign currency exchange contracts
Cash flow hedges:
Net (gains) losses on foreign currency exchange contracts not designated as hedging instruments	$ (5.7)	$ 48.9