Income Taxes (Components of Income from Continuing Operations Before Income Taxes and Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income from continuing operations before income taxes	$ 282.5	$ 292.9	$ 66.0
Current	46.2	3.1	26.2
Deferred	(2.7)	73.7	(27.2)
Total income tax expense (benefit)	$ 43.5	$ 76.8	$ (1.0)