Income Taxes - Additional Information (Detail) $ in Millions, $ in Millions		1 Months Ended		3 Months Ended			12 Months Ended
	Aug. 16, 2022	Dec. 31, 2022 USD ($) LegalEntity	Oct. 30, 2022 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 AUD ($)	Dec. 31, 2023 USD ($) Filer	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 AUD ($)	Dec. 31, 2022 AUD ($)	Dec. 31, 2020 USD ($)
Income Taxes [Line Items]
Corporate income tax rate							21.00%	21.00%	21.00%
Tax expense (benefit)				$ (36)			$ 189	$ 664	$ 629
Deferred income taxes (Q)							(22)	219	147
Deferred income taxes				147			147
Deferred tax liability				498			498
Net deferred tax assets		$ 2,958		3,240			3,240	2,958
Deferred tax assets, valuation allowance		2,333		2,595			2,595	2,333	$ 2,062			$ 2,127
Foreign undistributed net earnings for which no deferred taxes have been provided				2,676			2,676
Noncurrent income taxes (Q)		215		193			$ 193	$ 215
Percentage of the effect of unrecognized tax benefit, if recorded							1.00%	1.00%	0.00%
Reductions for tax positions of prior years							$ 0	$ 0	$ 0
Interest and penalties recognized							1	1	0
Interest income on income tax related payments							1	1	0
Amount accrued for payment of interest and penalties		3		4			4	$ 3
Minimum tax on book income of corporation	15.00%
Excise tax on net stock repurchases	1.00%
Excise tax for common stock repurchases	1.00%
Reversal of valuation allowance				58			$ 58
Remaining cumulative income position period							3 years
Norway [Member] | Internal Reorganization [Member]
Income Taxes [Line Items]
Deferred income taxes (Q)		$ 30
AWAB [Member] | Alumar Refinery [Member]
Income Taxes [Line Items]
Corporate income tax rate							15.25%	34.00%
Increase (decrease) in discrete income tax charge and benefit due tax holiday								$ (33)
Income tax holiday, description							The holiday related to production at the Alumar refinery was originally expected to end on December 31, 2027. During 2023, it was extended to December 31, 2032. The holiday related to the operation of the Juruti (Brazil) bauxite mine will end on December 31, 2026.
ASRI [Member] | Netherlands [Member]
Income Taxes [Line Items]
Tax expense (benefit)			$ (94)
ASRI [Member] | Norway [Member]
Income Taxes [Line Items]
Number of legal entities | LegalEntity		4
Number of legal entities reduced | LegalEntity		1
Foreign [Member]
Income Taxes [Line Items]
Deferred income taxes				147			$ 147
Percentage of net deferred tax asset relates to seven of Alcoa Corporation's income tax filers							90.00%
Number of Alcoa Corporation's income tax filers | Filer							6
Deferred tax liability				436			$ 436
Net deferred tax assets				2,190			2,190
Deferred tax assets, valuation allowance				1,607			$ 1,607
Foreign [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination Year Under Examination							2022
Foreign [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination Year Under Examination							2014
Foreign [Member] | Australian Taxation Office [Member]
Income Taxes [Line Items]
Assessed income tax amount exclusive of interest and penalties paid					$ 74	$ 107
Noncurrent income taxes (Q)		$ 174		199			$ 199	174		$ 293	$ 260
Foreign [Member] | AofA [Member]
Income Taxes [Line Items]
Deferred income taxes				185			185
Foreign [Member] | AWAB [Member]
Income Taxes [Line Items]
Deferred tax assets, valuation allowance		106		154			154	106
Foreign [Member] | Alcoa Canada Company [Member]
Income Taxes [Line Items]
Deferred income taxes				135			135
Foreign [Member] | Alcoa Lauralco Management Company [Member]
Income Taxes [Line Items]
Deferred income taxes				90			90
Foreign [Member] | Alcoa Wolinbec Company [Member]
Income Taxes [Line Items]
Deferred income taxes				39			39
Foreign [Member] | Alcoa Islandi [Member]
Income Taxes [Line Items]
Deferred income taxes				19			19
Foreign [Member] | Espanola [Member]
Income Taxes [Line Items]
Deferred tax assets, valuation allowance		$ 217						$ 217	150
Foreign [Member] | Espanola [Member]
Income Taxes [Line Items]
Deferred tax assets, valuation allowance									$ 103
Foreign [Member] | Fjaroaal [Member]
Income Taxes [Line Items]
Deferred income taxes				35			35
United States [Member]
Income Taxes [Line Items]
Deferred income taxes				0			0
Deferred tax liability				62			62
Net deferred tax assets				1,050			1,050
Deferred tax assets, valuation allowance				$ 988			$ 988
United States [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination Year Under Examination							2018
United States [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination Year Under Examination							2014