Commitments And Contingencies (Schedule Of Gross Settlement And Defense Costs) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) claim	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Aug. 21, 2012 USD ($)
Loss Contingencies [Line Items]
Payments Or Receipts For Asbestos Related Fees And Costs Net Of Insurance Recoveries		$ 31,100,000	$ 41,500,000	$ 63,900,000
Current asbestos liability		$ 66,500,000	65,000,000.0
Asbestos Commitments And Contingencies [Member]
Loss Contingencies [Line Items]
Asbestos Cumulative Claims Resolved | claim		141,000
Settlement / indemnity costs incurred		$ 35,300,000	45,500,000	63,000,000.0
Defense costs incurred		15,600,000	20,700,000	25,800,000
Gross Settlement And Defense Incurred Costs		50,900,000	66,200,000	88,800,000
Payments For Asbestos Related Settlement And Indemnity		24,700,000	38,900,000	61,500,000
Payments For Asbestos Related Defense And Related Fees Costs		16,700,000	21,400,000	26,500,000
InsuranceInflow		(10,300,000)	(18,800,000)	(24,100,000)
Payments Or Receipts For Asbestos Related Fees And Costs Net Of Insurance Recoveries		31,100,000	41,500,000	63,900,000
Cumulative Related Settlement Cost Incurred Before Insurance Recoveries		680,000,000
Cumulative Asbestos Settlement Cost Per Resolved Claim		4,800
Asbestos Settlement Cost Per Resolved Claim		13,900	15,800	$ 11,300
Estimated Funds Available From Post Bankruptcy Trusts To Pay Current And Future Claimants		36,000,000,000
Increase In Total Asbestos Liability	$ 255,000,000
Asbestos Liability		670,000,000	$ 712,000,000
Percentage Of Asbestos Liability Attributable To Settlement And Denfese Costs For Future Claims			85.00%
Current asbestos liability		$ 66,500,000	$ 65,000,000.0
Asbestos Commitments And Contingencies [Member] | Ronald Dummitt [Member]
Loss Contingencies [Line Items]
Court Judgment					$ 4,900,000