Investments (Tables)

3 Months Ended

Mar. 31, 2022

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):

First quarter ended March 31, 2022	Saudi Arabia Joint Venture			Mining			Energy		Other
Sales	$	897		$	231		$	62	$	117
Cost of goods sold		616			146			30		107
Net income (loss)		155			49			23		(28	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		39			14			9		(13	)
Other		—			—			1		(4	)
Alcoa Corporation’s equity in net income (loss) of    affiliated companies		39			14			10		(17	)
First quarter ended March 31, 2021
Sales	$	682		$	173		$	55	$	95
Cost of goods sold		503			123			25		63
Net income (loss)		45			(5	)		25		(2	)
Equity in net income (loss) of affiliated companies,    before reconciling adjustments		11			1			10		(1	)
Other		(4	)		—			—		3
Alcoa Corporation’s equity in net income of    affiliated companies		7			1			10		2