Financial Instruments and Risk Management - Fair Value Measurement (Details) - Fair value - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives | Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	$ 0.0	$ 0.0
Derivatives | Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	(22.6)	(15.0)
Currency risk | Derivatives | Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	0.0	0.0
Currency risk | Derivatives | Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	(6.1)	(2.9)
Currency risk | Derivatives | Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Assets	0.0	0.0
Currency risk | Derivatives | Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Assets	29.4	7.4
Interest rate risk | Derivatives | Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	0.0	0.0
Interest rate risk | Derivatives | Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Liabilities	$ (16.5)	$ (12.1)