Pension And Other Benefit Programs (Summary Of Fair Value Of Assets Plan) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	$ 1,467.7	$ 1,296.4
Investments measured at net asset value	10.7	64.0
Net assets	1,478.4	1,360.4	$ 1,529.7
Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	1,017.7	832.2
Collective Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	434.6	460.1
Cash, Other Short-Term Investments and Payables, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	12.9	1.5
Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	2.5	2.6
Investments measured at net asset value		3.9
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	0.3	(22.7)
Level 1 [Member] | Cash, Other Short-Term Investments and Payables, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	0.3	(22.7)
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	1,464.9	1,316.5
Level 2 [Member] | Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	1,017.7	832.2
Level 2 [Member] | Collective Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	434.6	460.1
Level 2 [Member] | Cash, Other Short-Term Investments and Payables, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	12.6	24.2
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	2.5	2.6
Level 3 [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Net assets measured at fair value	$ 2.5	$ 2.6