Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 10.8	$ 2.1	$ 2.1
State	2.4	3.3	0.1
International	30.5	35.1	37.0
Current income tax provision	43.7	40.5	39.2
Deferred:
Federal and state	10.3	1.4	41.8
International	5.0	(0.5)	(0.1)
Deferred income tax provision	15.3	0.9	41.7
Income tax expense	$ 59.0	$ 41.4	$ 80.9