Hedging Transactions and Derivative Financial Instruments (Volume of Copper Derivatives) (Details) - Designated as Hedging Instrument	Dec. 31, 2019 T / mo
April 2020 - June 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	202
July 2020 - September 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	202
October 2020 - December 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	201
January 2021 - March 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	201
January 2021 - March 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Volume of copper derivatives	256