Other Expense, Net - Schedule of Other Expenses (Income), Net (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)
Schedule Of Other Non operating Income Expense [Line Items]
Non-service costs - pension and other postretirement benefits (H)	$ 16	$ 9	$ 26
Interest income	(6)	(2)	(5)
Foreign currency (gains) losses, net	(1)	2	(11)
Net realized and unrealized losses	18	9	8
Deferred compensation	(8)	8	10
Judgment from legal proceeding (V)	65	0	0
Other, net	(2)	(7)	46
Total	$ 82	$ 19	$ 74
Alcoa Corporation
Schedule Of Other Non operating Income Expense [Line Items]
Tax agreement, indemnification of ultimate liability, percent			49.00%	49.00%
Spain
Schedule Of Other Non operating Income Expense [Line Items]
Income taxes receivable			$ 53	€ 45
Tax agreement, indemnification of ultimate liability, percent			33.66%	33.66%