Derivatives, Hedging Programs and Other Financial Instruments, Material Derivative Positions (Details)	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2019 MMBTU MWH mmlbs
Aluminum | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							100,400,000
Aluminum | Designated as Hedging Instrument | Sales
Derivative [Line Items]
Derivative non-monetary notional amount							400,000
Midwest premium swap contracts | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							73,600,000
Alloy Metal Hedge | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							13,500,000
Natural Gas | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount | MMBTU							8,230,000
Electricity | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount | MWH							350,880
Scenario, Forecast | Natural Gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage	75.00%	80.00%	80.00%	66.00%	66.00%	68.00%
Scenario, Forecast | Electricity
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage				36.00%	55.00%	54.00%