Investments (Tables)

6 Months Ended

Jun. 30, 2025

Equity Method Investments and Joint Ventures [Abstract]

Summary of Unaudited Financial Information for Alcoa Corporation's Equity Investments

A summary of unaudited financial information for Alcoa Corporation’s equity investments is as follows (amounts represent 100% of investee financial information):

Second quarter ended June 30, 2025	Saudi Arabia Joint Venture			Mining			Energy			Other
Sales	$	824		$	192		$	60		$	111
Cost of goods sold		687			109			27			101
Net (loss) income		(8	)		25			29			(25	)
Equity in net (loss) income of affiliated companies,    before reconciling adjustments		(2	)		11			12			(12	)
Other		(6	)		(3	)		2			2
Alcoa Corporation’s equity in net (loss) income of    affiliated companies		(8	)		8			14			(10	)
Second quarter ended June 30, 2024
Sales	$	804		$	158		$	59		$	114
Cost of goods sold		613			104			25			104
Net income (loss)		102			14			29			(20	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		26			6			11			(9	)
Other		(4	)		—			—			12
Alcoa Corporation’s equity in net income of    affiliated companies		22			6			11			3
Six months ended June 30, 2025
Sales	$	1,780		$	360		$	118		$	222
Cost of goods sold		1,462			213			49			201
Net income (loss)		5			44			58			(35	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		1			20			23			(17	)
Other		—			(3	)		2			(5	)
Alcoa Corporation’s equity in net income (loss) of    affiliated companies		1			17			25			(22	)
Six months ended June 30, 2024
Sales	$	1,515		$	273		$	122		$	229
Cost of goods sold		1,212			207			50			209
Net income (loss)		94			9			60			(36	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		24			4			23			(17	)
Other		(12	)		—			(1	)		7
Alcoa Corporation’s equity in net income (loss) of    affiliated companies		12			4			22			(10	)