Derivative Instruments - Gains and Losses text (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Foreign exchange transaction gains (losses)	$ (6.2)	$ (15.8)	$ 20.6
Cash Flow Hedges
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Reclassification expected during next 12 months	(0.1)
Foreign Exchange Forward Contracts
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Gain (loss) from settlements and changes in fair value	$ 8.0	$ 21.0	$ (19.2)

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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