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Derivatives, Hedging Programs and Other Financial Instruments - Summary of Derivative Positions (Details) Mmlb in Millions | 9 Months Ended
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Sep. 30, 2025 EUR (€) Mmlb MMBTU
Purchase | Aluminum |
Derivative [Line Items] |
Derivative non-monetary notional amount | 64.1
Purchase | Aluminum | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Purchase | Aluminum | Maximum |
Derivative [Line Items] |
Derivative maturity period | Nov. 30, 2026
Purchase | Fixed Price Purchase Contracts for MWTP |
Derivative [Line Items] |
Derivative non-monetary notional amount | 64.1
Purchase | Fixed Price Purchase Contracts for MWTP | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Purchase | Fixed Price Purchase Contracts for MWTP | Maximum |
Derivative [Line Items] |
Derivative maturity period | Nov. 30, 2026
Purchase | Alloying Metals |
Derivative [Line Items] |
Derivative non-monetary notional amount | 6.8
Purchase | Alloying Metals | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Purchase | Alloying Metals | Maximum |
Derivative [Line Items] |
Derivative maturity period | Dec. 31, 2027
Purchase | Natural Gas |
Derivative [Line Items] |
Derivative non-monetary notional amount | MMBTU | 3,300,000
Purchase | Natural Gas | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Purchase | Natural Gas | Maximum |
Derivative [Line Items] |
Derivative maturity period | Dec. 31, 2027
Purchase | Euro |
Derivative [Line Items] |
Derivative notional amount | € | € 1,700,000
Purchase | Euro | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Purchase | Euro | Maximum |
Derivative [Line Items] |
Derivative maturity period | Jul. 31, 2027
Sales | Aluminum |
Derivative [Line Items] |
Derivative non-monetary notional amount | 23.5
Sales | Aluminum | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Sales | Aluminum | Maximum |
Derivative [Line Items] |
Derivative maturity period | Mar. 31, 2026
Sales | Fixed Price Sale Contracts for MWTP |
Derivative [Line Items] |
Derivative non-monetary notional amount | 23.5
Sales | Fixed Price Sale Contracts for MWTP | Minimum |
Derivative [Line Items] |
Derivative maturity period | Oct. 31, 2025
Sales | Fixed Price Sale Contracts for MWTP | Maximum |
Derivative [Line Items] |
Derivative maturity period | Apr. 30, 2026

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