Hedging Transactions and Derivative Financial Instruments (Volume of Copper Derivatives) (Details) - Contracts not designated as hedging instruments	Dec. 31, 2020 tons_per_month
January 2021 - March 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	256
April 2021 - June 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	256
July 2021 - September 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	222
October 2021 - December 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	222