Investments (Tables)

12 Months Ended

Dec. 31, 2018

Equity Method Investments And Joint Ventures [Abstract]

Summary of Investment

December 31,	2018		2017
Equity investments	$	1,350	$	1,400
Other investments		10		10
	$	1,360	$	1,410

Schedule of Equity Investment

The following table summarizes information of Alcoa Corporation’s equity investments as of December 31, 2018 and 2017 (the Elysis Limited Partnership began in June 2018 (see below)):

Investee	Country	Nature of investment(4)	Ownership interest
Ma’aden Aluminum Company(1)	Saudi Arabia	Aluminum smelter and casthouse		25.1	%
Ma’aden Bauxite and Alumina Company(1)	Saudi Arabia	Bauxite mine and alumina refinery		25.1	%	(5)
Ma’aden Rolling Company(1)	Saudi Arabia	Aluminum rolling mill		25.1	%
Halco Mining, Inc.(2)	Guinea	Bauxite mine		45	%	(5)
Energetica Barra Grande S.A.	Brazil	Hydroelectric generation facility		42.18	%
Pechiney Reynolds Quebec, Inc.(3)	Canada	Aluminum smelter		50	%
Consorcio Serra do Facão	Brazil	Hydroelectric generation facility		34.97	%
Mineração Rio do Norte S.A.	Brazil	Bauxite mine		18.2	%	(5)
Manicouagan Power Limited Partnership	Canada	Hydroelectric generation facility		40	%
Elysis Limited Partnership	Canada	Aluminum smelting technology		48.235	%

⁽¹⁾ See Saudi Arabia Joint Venture below for additional information.

⁽²⁾ Halco Mining, Inc. owns 100% of Boké Investment Company, which owns 51% of Compagnie des Bauxites de Guinée.

⁽³⁾ Pechiney Reynolds Quebec, Inc. owns a 50.1% interest in the Bécancour smelter in Quebec, Canada thereby entitling Alcoa Corporation to a 25.05% interest in the smelter. Through two wholly-owned Canadian subsidiaries, Alcoa Corporation also owns 49.9% of the Bécancour smelter.

⁽⁴⁾ Each of the investees either owns the facility listed or has an ownership interest in an entity that owns the facility listed.

⁽⁵⁾ A portion or all of each of these ownership interests are held by majority-owned subsidiaries that are part of AWAC.

Summary of Financial Information for Alcoa Corporation's Equity Investments

Financial information for these equity investments is as follows (amounts represent 100% of the investee’s financial information):

	Saudi Arabia Joint Venture(1)			Halco Mining, Inc.			Energetica Barra Grande S.A.			Pechiney Reynolds Quebec, Inc.			Consorcio Serra do Facão			Mineração Rio do Norte S.A.			Manicouagan Power L.P.			DBNGP Trust(2)		Total
Profit and loss data—    year ended    December 31, 2018
Sales	$	3,986		$	402		$	84		$	120		$	93		$	400		$	106		$	—	$	5,191
Cost of goods sold		3,334			268			66			110			71			254			9			—	$	4,112
Income    before income taxes		301			41			17			8			21			120			96			—	$	604
Net income		9			38			6			16			19			33			89			—	$	210
Equity in net    income of affiliated    companies, before    reconciling    adjustments		2			17			3			8			7			6			36			—	$	79
Other		(13	)		(2	)		—			(1	)		(1	)		(8	)		(3	)		—	$	(28	)
Alcoa    Corporation’s    equity in net (loss)    income of affiliated    companies		(11	)		15			3			7			6			(2	)		33			—	$	51
Profit and loss data—    year ended    December 31, 2017
Sales	$	3,032		$	416		$	131		$	332		$	103		$	350		$	105		$	—	$	4,469
Cost of goods sold		2,776			266			117			292			48			273			9			—		3,781
(Loss) income    before income taxes		(142	)		50			13			35			45			35			96			—		132
Net (loss) income		(157	)		47			5			23			46			30			88			—		82
Equity in net (loss)    income of affiliated    companies, before    reconciling    adjustments		(39	)		21			2			11			16			6			35			—		52
Other		9			(1	)		—			—			—			—			2			—		10
Alcoa    Corporation’s    equity in net (loss)    income of affiliated    companies		(30	)		20			2			11			16			6			37			—		62
Profit and loss data—    year ended    December 31, 2016
Sales	$	1,970		$	437		$	60		$	309		$	90		$	451		$	104		$	86	$	3,507
Cost of goods sold		1,905			242			35			272			65			297			10			18		2,844
(Loss) income    before income taxes		(295	)		53			16			36			8			152			94			21		85
Net (loss) income		(295	)		50			15			16			5			129			87			14		21
Equity in net (loss)    income of affiliated    companies, before    reconciling    adjustments		(75	)		23			6			8			2			23			35			3		25
Other		7			2			(1	)		(4	)		—			(1	)		—			—		3
Alcoa    Corporation’s    equity in net (loss)    income of affiliated    companies		(68	)		25			5			4			2			22			35			3		28

	Saudi Arabia Joint Venture(1)		Halco Mining, Inc.		Energetica Barra Grande S.A.		Pechiney Reynolds Quebec, Inc.		Consorcio Serra do Facão		Mineração Rio do Norte S.A.		Manicouagan Power L.P.		DBNGP Trust(2)		Total
Balance sheet data—as of    December 31, 2018
Current assets	$	1,684	$	58	$	18	$	139	$	43	$	127	$	23	$	—	$	2,092
Noncurrent assets		9,115		164		224		97		242		653		76		—		10,571
Current liabilities		1,379		10		5		49		20		116		11		—		1,590
Noncurrent liabilities		6,101		17		18		4		83		422		—		—		6,645
Balance sheet data—as of    December 31, 2017
Current assets	$	1,415	$	40	$	44	$	140	$	79	$	121	$	23	$	—	$	1,862
Noncurrent assets		9,373		174		285		106		261		744		72		—		11,015
Current liabilities		1,331		1		48		65		25		220		9		—		1,699
Noncurrent liabilities		6,191		12		6		12		117		413		—		—		6,751

⁽¹⁾ The amounts included in this column represent the combined financial information related to Ma’aden Aluminum Company, Ma’aden Bauxite and Alumina Company, and Ma’aden Rolling Company.

⁽²⁾ AofA sold its interest in the Dampier to Bunbury Natural Gas Pipeline (DBNGP) Trust in April 2016 (see DBNGP Trust below).