Stock Transactions And Stock-Based Compensation (Components of Stock-Based Compensation Program) (Details) - USD ($) $ in Millions		12 Months Ended
	Dec. 18, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 1.0	$ 18.4	$ 13.3	$ 12.3
Income tax benefit		(4.0)	(3.4)	(4.1)
Total stock-based compensation expense, net of income taxes		14.4	9.9	8.2
RSUs/PSUs:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		11.2	8.2	7.6
Income tax benefit		(2.4)	(2.1)	(2.5)
Total stock-based compensation expense, net of income taxes		8.8	6.1	5.1
Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense		7.2	5.1	4.7
Income tax benefit		(1.6)	(1.3)	(1.6)
Total stock-based compensation expense, net of income taxes		$ 5.6	$ 3.8	$ 3.1