Investments (Tables)

6 Months Ended

Jun. 30, 2020

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, 2020	Saudi Arabia Joint Venture			Mining			Energy			Other
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
Second quarter ended June 30, 2019
Sales	$	976		$	187		$	64		$	25
Cost of goods sold		821			132			35			23
Net (loss) income		(57	)		2			26			—
Equity in net (loss) income of affiliated companies,    before reconciling adjustments		(14	)		3			10			—
Other		(2	)		(2	)		1			—
Alcoa Corporation’s equity in net (loss) income of    affiliated companies		(16	)		1			11			—
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
Six months ended June 30, 2019
Sales	$	1,934		$	415		$	127		$	39
Cost of goods sold		1,673			281			64			38
Net (loss) income		(125	)		—			54			(6	)
Equity in net (loss) income of affiliated companies,    before reconciling adjustments		(31	)		8			21			(3	)
Other		4			6			1			2
Alcoa Corporation’s equity in net (loss) income of    affiliated companies		(27	)		14			22			(1	)