Statement of Consolidated Operations (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Sales (E)	$ 2,870	$ 2,381
Cost of goods sold (exclusive of expenses below)	2,292	2,025
Selling, general administrative, and other expenses	52	60
Research and development expenses	7	7
Provision for depreciation, depletion, and amortization	182	170
Restructuring and other charges, net (D)	7	2
Interest expense	42	30
Other income, net (Q)	(24)	(132)
Total costs and expenses	2,558	2,162
Income before income taxes	312	219
Provision for income taxes	93	80
Net income	219	139
Less: Net income attributable to noncontrolling interest	44	59
NET INCOME ATTRIBUTABLE TO ALCOA CORPORATION	$ 175	$ 80
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (F):
Basic	$ 0.94	$ 0.43
Diluted	$ 0.93	$ 0.43