Debt, Interest Income, Expense and Other Finance Costs - Interest Income (Expense), and Other Financing Costs, net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Debt, Interest Income, Expense and Other Finance Costs [Abstract]
Interest income	$ 0.9	$ 1.1
Interest expense and other financing costs	(16.2)	(20.5)
Interest income (expense) and other financing costs, net	$ (15.4)	$ (19.4)