Description of Business and Significant Accounting Policies (Schedule Of Estimated Useful Lives Of Assets) (Details)	Dec. 31, 2023
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	40 years
Plant and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	25 years
Ethylene pipeline
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	35 years
Minimum | Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Maximum | Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	15 years