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Business Combinations, Goodwill and Intangible Assets - Schedule of Purchase Consideration (Details) - Alcoa Warrick LLC [Member] - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Mar. 31, 2021 | Dec. 31, 2021
Business Acquisition [Line Items] |  |
Contract purchase price | $ 670.0 | $ 670.0
Working capital adjustment |  | 31.0
Initial outstanding indebtedness – Other postretirement benefits liabilities |  | (83.5)
Cash paid at acquisition close on March 31, 2021 |  | 617.5
Estimated post-close adjustments |  | (12.7)
Preliminary purchase consideration to allocate |  | 604.8
Revision to estimated post-close adjustments |  | 4.4
Final purchase consideration to allocate |  | $ 609.2

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