Subsequent Events	12 Months Ended
Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	W. Subsequent Events On January 8, 2024, Alcoa announced the full curtailment of the Kwinana refinery beginning in the second quarter of 2024. The refinery has an annual nameplate capacity of 2.2 million metric tons and has been operating at approximately 80 percent of its nameplate capacity since January 2023, when the Company reduced production in response to a domestic natural gas shortage in Western Australia due to production challenges experienced by key gas suppliers. The Company’s decision to fully curtail the refinery was made based on a variety of factors, including the refinery’s age, scale, operating costs and current bauxite grades, in addition to current market conditions. The refinery currently has approximately 800 employees and this number will be reduced to approximately 250 in the third quarter of 2024, when alumina production will cease. Certain processes will continue until about the third quarter of 2025, when the employee number will be further reduced to approximately 50. In the first quarter of 2024, Alcoa will record restructuring charges between $180 and $200 related to the curtailment of the refinery. The charges include approximately $81 for water management costs, $55 for employee related costs, $26 for asset retirement obligations, and $18 of other costs. Alcoa’s share of related cash outlays of approximately $115 (which includes existing employee related liabilities and asset retirement obligations) is expected to be spent in 2024 ($80) and 2025 ($35).

Subsequent Events

12 Months Ended

Dec. 31, 2023

W. Subsequent Events

On January 8, 2024, Alcoa announced the full curtailment of the Kwinana refinery beginning in the second quarter of 2024. The refinery has an annual nameplate capacity of 2.2 million metric tons and has been operating at approximately 80 percent of its nameplate capacity since January 2023, when the Company reduced production in response to a domestic natural gas shortage in Western Australia due to production challenges experienced by key gas suppliers. The Company’s decision to fully curtail the refinery was made based on a variety of factors, including the refinery’s age, scale, operating costs and current bauxite grades, in addition to current market conditions. The refinery currently has approximately 800 employees and this number will be reduced to approximately 250 in the third quarter of 2024, when alumina production will cease. Certain processes will continue until about the third quarter of 2025, when the employee number will be further reduced to approximately 50.

In the first quarter of 2024, Alcoa will record restructuring charges between $180 and $200 related to the curtailment of the refinery. The charges include approximately $81 for water management costs, $55 for employee related costs, $26 for asset retirement obligations, and $18 of other costs. Alcoa’s share of related cash outlays of approximately $115 (which includes existing employee related liabilities and asset retirement obligations) is expected to be spent in 2024 ($80) and 2025 ($35).