Statement of Consolidated Operations (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Sales (E)	$ 3,018	$ 2,906	$ 6,387	$ 5,505
Cost of goods sold (exclusive of expenses below)	2,652	2,533	5,090	4,937
Selling, general administrative, and other expenses	82	69	153	129
Research and development expenses	12	13	24	24
Provision for depreciation, depletion, and amortization	153	163	301	324
Restructuring and other charges, net (D)	14	18	19	220
Interest expense	56	40	109	67
Other (income) expenses, net (P)	(112)	(22)	(138)	37
Total costs and expenses	2,857	2,814	5,558	5,738
Consolidated income (loss) before income taxes	161	92	829	(233)
Provision for income taxes	10	61	130	43
Net income (loss)	151	31	699	(276)
Less: Net (loss) income attributable to noncontrolling interest	(13)	11	(13)	(44)
NET INCOME (LOSS) ATTRIBUTABLE TO ALCOA CORPORATION	$ 164	$ 20	$ 712	$ (232)
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (F):
Basic	$ 0.63	$ 0.11	$ 2.71	$ (1.29)
Diluted	$ 0.62	$ 0.11	$ 2.69	$ (1.29)