Income Taxes (Deferred Tax Valuation Allowance) (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Movement in Deferred Tax Valuation Allowances [Roll Forward]
Balance at beginning of year	$ 43.8	$ 67.6	$ 73.5
Additions charged to provision for income taxes	0.4	2.2	0.1
Deferred tax assets realized or written-off	0.1	(28.3)	(6.0)
Other, net	(0.6)	2.3	0.0
Balance at end of year	$ 43.7	$ 43.8	$ 67.6