Shareholders' Equity - Components of Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Millions	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ 2,483.2	$ 2,396.7	$ 2,377.4	$ 2,453.6	$ 2,605.4	$ 2,542.8	$ 2,639.0	$ 2,761.5
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(172.0)			(72.1)
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	(37.1)			(81.2)
Translation loss on long-term intercompany loans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(127.6)			(133.3)
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	(108.2)			(111.4)
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	0.3			0.7
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (444.6)	$ (422.3)	$ (437.8)	$ (397.3)	$ (432.8)	$ (479.1)	$ (505.8)	$ (441.0)