Statement of Consolidated Operations (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Sales (E)	$ 2,148	$ 2,711	$ 4,529	$ 5,430
Cost of goods sold (exclusive of expenses below)	1,932	2,189	3,957	4,369
Selling, general administrative, and other expenses	44	68	104	152
Research and development expenses	5	7	12	14
Provision for depreciation, depletion, and amortization	152	174	322	346
Restructuring and other charges, net (D)	37	370	39	483
Interest expense	32	30	62	60
Other expenses (income), net (Q)	51	50	(81)	91
Total costs and expenses	2,253	2,888	4,415	5,515
(Loss) income before income taxes	(105)	(177)	114	(85)
Provision for income taxes	45	116	125	266
Net loss	(150)	(293)	(11)	(351)
Less: Net income attributable to noncontrolling interest	47	109	106	250
NET LOSS ATTRIBUTABLE TO ALCOA CORPORATION	$ (197)	$ (402)	$ (117)	$ (601)
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (F):
Basic	$ (1.06)	$ (2.17)	$ (0.63)	$ (3.24)
Diluted	$ (1.06)	$ (2.17)	$ (0.63)	$ (3.24)