Income Taxes (Schedule Of The Reconciliation To U.S. Statutory Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Continuing operations tax at statutory rate	$ 62.9	$ 51.0	$ 77.7
Increase in valuation allowances on deferred domestic income tax assets	0.1	10.0	9.1
State income tax expense, net of federal benefit	12.4	9.2	7.9
Domestic production activities			(5.8)
Statute closures	(3.8)	(9.6)	(2.3)
State deferred tax adjustments	(1.9)
Capital loss utilization on WAVE earnings	(4.4)
2017 Tax Act		(1.2)	(82.5)
Excess tax benefits on share-based compensation	(3.2)	(3.8)
Tax on foreign and foreign-source income	(1.9)	(4.4)
Other	(3.1)	1.9	(2.6)
Income tax expense (benefit)	$ 57.1	$ 53.1	$ 1.5