Subsequent Events	3 Months Ended
Mar. 31, 2025
Subsequent Events [Abstract]
Subsequent Events	R. Subsequent Events On April 28, 2025, Alcoa’s San Ciprián complex was impacted by the widespread power outage across Spain. As a result of the outage, both the refinery and smelter at the complex were affected. Due to the preliminary nature of the information, Alcoa is unable to reasonably estimate the impact to the Company’s results of operations until a thorough assessment is complete.

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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