(Financial Instruments and Hedging Activities - Additional Information) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Cumulative deferred hedging gain (loss), after tax, included in accumulated other comprehensive income	$ 27.1
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, notional amount	724.7
Intercompany Debt [Member]
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign currency denominated debt designated to hedge investments in certain foreign subsidiaries and affiliates	4,100.0
Debt [Member]
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign currency denominated debt designated to hedge investments in certain foreign subsidiaries and affiliates	11,700.0
Interest Rate Risk [Member] | Fair Value Hedging [Member]
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative instruments, gain (loss) recognized in income, net	(19.1)
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments	$ (25.3)
Royalty Arrangement [Member]
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Period covered by hedge	18 months
Derivative, notional amount	$ 746.0