Statement of Changes in Consolidated Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Non-controlling Interest [Member]
Balance at Dec. 31, 2021	$ 6,284	$ 2	$ 9,577	$ (315)	$ (4,592)	$ 1,612
Net income (loss)	38			(123)		161
Other comprehensive income (loss) (G)	960				1,053	(93)
Stock-based compensation (N)	40		40
Net effect of tax withholding for compensation plans and exercise of stock options (N)	3		3
Repurchase of common stock (N)	(500)		(440)	(60)
Dividends paid on Alcoa common stock ($0.10 per share) (N)	(72)			(72)
Contributions	214					214
Distributions	(379)					(379)
Other	1		3			(2)
Balance at Dec. 31, 2022	6,589	2	9,183	(570)	(3,539)	1,513
Net income (loss)	(773)			(651)		(122)
Other comprehensive income (loss) (G)	(60)				(106)	46
Stock-based compensation (N)	35		35
Net effect of tax withholding for compensation plans and exercise of stock options (N)	(33)		(33)
Dividends paid on Alcoa common stock ($0.10 per share) (N)	(72)			(72)
Contributions	188					188
Distributions	(30)					(30)
Other	1		2			(1)
Balance at Dec. 31, 2023	5,845	2	9,187	(1,293)	(3,645)	1,594
Net income (loss)	24			60		(36)
Other comprehensive income (loss) (G)	(467)				(366)	(101)
Stock-based compensation (N)	36		36
Net effect of tax withholding for compensation plans and exercise of stock options (N)	(15)		(15)
Dividends paid on Alcoa common stock ($0.10 per share) (N)	(89)			(89)
Dividends paid on Alcoa preferred stock ($0.10 per share) (N)	(1)			(1)
Contributions	65					65
Distributions	(49)					(49)
Acquisition of noncontrolling interest (C)	(193)	1	2,377		(1,099)	(1,472)
Other	1		2			(1)
Balance at Dec. 31, 2024	$ 5,157	$ 3	$ 11,587	$ (1,323)	$ (5,110)	$ 0