Shareholders' Equity - Components of Accumulated Other Comprehensive Loss, Net of Tax (Parenthetical) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Translation loss on derivative instruments, net of income tax benefit of $(18.8) and (34.9), respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	$ (18.8)	$ (34.9)
Defined benefit pension plans and Retiree health care plan | Defined benefit pension plans, net of income tax benefit of $(34.0) and $(38.2), respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	(34.0)	(38.2)
Defined benefit pension plans and Retiree health care plan | Retiree health care plan, net of income taxes of $1.7 and $1.8, respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	$ 1.7	$ 1.8