Income Taxes - Schedule of components of loss before income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes	$ 42.8	$ (210.8)	$ (341.8)
United States
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes	(38.6)	(65.6)	(231.4)
Other countries
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes	$ 81.4	$ (145.2)	$ (110.4)