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Derivatives, Hedging Programs and Other Financial Instruments - Summary of (Gain) Loss Associated with Derivative Contracts (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded | $ 690.5 | $ 718.4 | $ 1,333.4 | $ 1,449.5
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded | Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded | Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded | Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded
Loss recognized in our Statements of Consolidated Income - Unrealized mark-to-market loss |  |  | $ 2.2 |
Not Designated as Hedging Instrument |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | $ 2.2 | $ 0.2 | 2.2 | $ 0.1
Not Designated as Hedging Instrument | Alloying Metals |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Loss recognized in our Statements of Consolidated Income - Unrealized mark-to-market loss |  | 0.2 |  | 0.1
Not Designated as Hedging Instrument | Electricity |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Loss recognized in our Statements of Consolidated Income - Unrealized mark-to-market loss | 2.0 |  | 2.0 |
Reclassification from AOCI due to forecasted transactions probable of not occurring | 0.2 |  | 0.2 |
Cash Flow Hedges |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
Total of income and expense line items presented in our Statements of Consolidated Income (Loss) in which the effects of cash flow hedges are recorded | 690.5 | 718.4 | 1,333.4 | 1,449.5
Cash Flow Hedges | Designated as Hedging Instrument |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | (2.0) | 5.5 | 0.1 | 5.7
Cash Flow Hedges | Designated as Hedging Instrument | Aluminum |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | (2.7) | 5.2 | (0.7) | $ 5.7
Cash Flow Hedges | Designated as Hedging Instrument | Alloying Metals |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | (0.5) |  | (0.5) |
Cash Flow Hedges | Designated as Hedging Instrument | Natural Gas |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | 0.4 | $ 0.3 | 0.7 |
Cash Flow Hedges | Designated as Hedging Instrument | Electricity |  |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |  |
(Gain) loss recognized in our Statements of Consolidated Income | $ 0.8 |  | $ 0.6 |

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- Definition The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 924 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 11.L) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(a),(d)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 + Details
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