Derivative Financial Instruments (Fair Value Of Derivative Instruments In Statement Of Financial Position) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 337.3	$ 141.4
Derivative liabilities	190.5	194.0
Call option | Long-term – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	4.3
Embedded derivative financial instruments | Long-term – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	4.3
Derivatives designated as hedging instruments | Foreign exchange contract
Derivatives, Fair Value [Line Items]
Derivative assets	251.4	129.1
Derivative liabilities	174.9	173.0
Derivatives designated as hedging instruments | Foreign exchange contract | Current – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative assets	215.8	94.3
Derivative liabilities	151.6	125.0
Derivatives designated as hedging instruments | Foreign exchange contract | Long-term – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative assets	35.6	34.8
Derivative liabilities	23.3	48.0
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative assets	85.9	8.0
Derivative liabilities	15.6	16.7
Derivatives not designated as hedging instruments | Foreign exchange contract | Current – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative assets	85.6	7.6
Derivative liabilities	15.6	16.3
Derivatives not designated as hedging instruments | Foreign exchange contract | Long-term – Derivative financial instruments
Derivatives, Fair Value [Line Items]
Derivative assets	0.3	0.4
Derivative liabilities	0.0	0.4
Cash flow hedging | Foreign exchange contract
Derivatives, Fair Value [Line Items]
Gain (loss) recognized in OCI (effective portion)	$ 28.0	$ 10.3	$ (75.4)