Income Taxes (Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal:
Current	$ (2.2)	$ 4.7	$ 0.0
Deferred	(21.0)	(1.1)	2.1
State:
Current	0.9	(2.1)	2.6
Deferred	(4.9)	1.7	0.2
Foreign:
Current	0.1	2.0	2.4
Deferred	2.7	(7.6)	(16.5)
Total income tax benefit	$ (24.4)	$ (2.4)	$ (9.2)