Other Financial Information - Additional Information (Detail) $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($)	Apr. 30, 2016 Refinery	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 Subsidiary
Other Non operating Income Expense [Line Items]
Interest income				$ 62	$ 50
Net gain from asset sales				(18)	(10)	$ 354
Number of alumina refineries to be powered under supplied agreement | Refinery		3
VAT credits payable				58	51
Sales				10,551	12,451	12,152
Reversed the allowance with credit of restructuring and other charges, net	$ (83)
Valuation allowance with credit to cost of goods sold	$ (46)
Restricted cash				91
Capital improvements at the site				118
Restart Costs				35
Capital investment expenditures				28
Dampier to Bunbury Natural Gas Pipeline [Member] | AofA [Member]
Other Non operating Income Expense [Line Items]
Investment percentage		30.00%
Prepayments made under the agreement for future gas transmission services				297	285
Brazil [Member]
Other Non operating Income Expense [Line Items]
Sales				$ 735	$ 527	610
Brazil [Member] | Alcoa World Alumina Brazil and Alcoa Aluminio [Member]
Other Non operating Income Expense [Line Items]
Number of subsidiaries | Subsidiary							2
Sales			$ 34
Brazil [Member] | Alcoa World Alumina Brazil and Alcoa Aluminio [Member] | Other Noncurrent Assets [Member]
Other Non operating Income Expense [Line Items]
Additional VAT credits recorded			95
Brazil [Member] | Alcoa World Alumina Brazil and Alcoa Aluminio [Member] | Other Income Net [Member]
Other Non operating Income Expense [Line Items]
Interest income			14
Brazil [Member] | Alcoa World Alumina Brazil and Alcoa Aluminio [Member] | Other Noncurrent Liabilities [Member]
Other Non operating Income Expense [Line Items]
VAT credits payable			$ 47			47
Eastalco Site Sale And Warrick Rolling Mill [Member]
Other Non operating Income Expense [Line Items]
Net gain from asset sales						$ 354