Income Taxes (Unrecognized Tax Benefits And Associated Interest And Penalties) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Federal, State and Foreign Tax
Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits, beginning balance	$ 91.0	$ 90.4
Reductions for tax positions related to prior years	(62.4)	(11.5)
Additions for tax positions related to current year	72.9	21.1
Reductions for tax positions due to settlements	(20.8)	(9.0)
Unrecognized tax benefits, ending balance	80.7	91.0
Accrued Interest and Penalties
Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits, beginning balance	2.8	5.9
Unrecognized tax benefits, ending balance	$ 0.1	$ 2.8