Subsequent Events	6 Months Ended
Jun. 30, 2025
Subsequent Events [Abstract]
Subsequent Events	R. Subsequent Events On June 30, 2025, the collective bargaining agreement with the Australian Workers Union (AWU) representing approximately 400 hourly employees at the Portland, Australia smelter expired. The AWU did not accept the latest offer, proposed by the Company on July 25, 2025, and elected to undertake protected industrial action in the form of a 48-hour work stoppage beginning August 5, 2025. While negotiations continue, the Company has contingency plans to maintain safety and minimize operating disruptions at the Portland smelter if the industrial action were to occur. On July 14, 2025, Alcoa Corporation and IGNIS EQT announced the restart for the San Ciprián smelter in Spain would resume, after the restart was paused following a widespread power outage across Spain on April 28, 2025. The Company estimates that the restart will be completed by mid-2026.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org/855/tableOfContent

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

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