Investments (Tables)

6 Months Ended

Jun. 30, 2021

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, 2021	Saudi Arabia Joint Venture			Mining			Energy			Other
Sales	$	741		$	197		$	60		$	96
Cost of goods sold		508			146			32			78
Net income (loss)		102			25			27			(4	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		26			9			11			(2	)
Other		—			(1	)		—			8
Alcoa Corporation’s equity in net income of    affiliated companies		26			8			11			6
Second quarter ended June 30, 2020
Sales	$	507		$	209		$	47		$	85
Cost of goods sold		446			130			24			75
Net (loss) income		(75	)		(5	)		20			(6	)
Equity in net (loss) income of affiliated companies,    before reconciling adjustments		(19	)		3			7			(3	)
Other		(1	)		2			1			5
Alcoa Corporation’s equity in net (loss) income of    affiliated companies		(20	)		5			8			2
Six months ended June 30, 2021
Sales	$	1,423		$	370		$	115		$	191
Cost of goods sold		1,011			269			57			171
Net income (loss)		147			20			52			(6	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		37			10			21			(3	)
Other		(4	)		(1	)		—			11
Alcoa Corporation’s equity in net income of    affiliated companies		33			9			21			8
Six months ended June 30, 2020
Sales	$	1,092		$	427		$	106		$	158
Cost of goods sold		908			278			50			142
Net (loss) income		(88	)		4			47			(15	)
Equity in net (loss) income of affiliated companies,    before reconciling adjustments		(22	)		9			18			(7	)
Other		(4	)		(1	)		(1	)		10
Alcoa Corporation’s equity in net (loss) income of    affiliated companies		(26	)		8			17			3