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, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income from continuing operations before income taxes	$ 444.8	$ 522.1	$ 282.5
Current	105.9	80.5	46.2
Deferred	(23.1)	12.6	(2.7)
Total income tax expense	$ 82.8	$ 93.1	$ 43.5