Statement of Consolidated Operations (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Sales (D)	$ 2,719	$ 3,090
Cost of goods sold (exclusive of expenses below) (H)	2,180	2,302
Selling, general administrative, and other expenses	84	67
Research and development expenses	7	8
Provision for depreciation, depletion, and amortization	172	194
Restructuring and other charges, net (C)	113	(19)
Interest expense	30	26
Other expenses, net (N)	41	21
Total costs and expenses	2,627	2,599
Income before income taxes	92	491
Provision for income taxes	150	151
Net (loss) income	(58)	340
Less: Net income attributable to noncontrolling interest	141	145
NET (LOSS) INCOME ATTRIBUTABLE TO ALCOA CORPORATION	$ (199)	$ 195
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (E):
Basic	$ (1.07)	$ 1.05
Diluted	$ (1.07)	$ 1.04