Statement of Consolidated Operations (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Sales to unrelated parties	$ 2,725	$ 2,075	$ 7,837	$ 6,028
Sales to related parties (A)	239	254	641	753
Total sales (E)	2,964	2,329	8,478	6,781
Cost of goods sold (exclusive of expenses below)	2,361	1,968	6,713	5,775
Selling, general administrative, and other expenses (A)	70	92	214	267
Research and development expenses	8	8	23	26
Provision for depreciation, depletion, and amortization	194	181	563	536
Restructuring and other charges (D)	(10)	17	12	109
Interest expense	26	67	77	197
Other expenses (income), net (N)	27	(106)	(67)	(90)
Total costs and expenses	2,676	2,227	7,535	6,820
Income (loss) before income taxes	288	102	943	(39)
Provision for income taxes (L)	119	92	328	178
Net income (loss)	169	10	615	(217)
Less: Net income attributable to noncontrolling interest	56	20	202	58
NET INCOME (LOSS) ATTRIBUTABLE TO ALCOA CORPORATION	$ 113	$ (10)	$ 413	$ (275)
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (F):
Basic	$ 0.61	$ (0.06)	$ 2.24	$ (1.51)
Diluted	$ 0.60	$ (0.06)	$ 2.21	$ (1.51)