Statement of Consolidated Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
NET (LOSS) INCOME ATTRIBUTABLE TO ALCOA CORPORATION	$ (102)	$ 549	$ (333)	$ 1,018
Net income, Noncontrolling interest	(19)	125	(20)	209
Net (loss) income	(121)	674	(353)	1,227
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits, Alcoa Corporation	10	52	14	74
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits, Noncontrolling interest	(2)		(2)	1
Change in unrecognized net actuarial loss and prior service cost/benefit related to pension and other postretirement benefits	8	52	12	75
Foreign currency translation adjustments, Alcoa Corporation	25	(370)	27	(44)
Foreign currency translation adjustments, Noncontrolling interest	11	(132)	26	(34)
Foreign currency translation adjustments	36	(502)	53	(78)
Net change in unrecognized gains/losses on cash flow hedges, Alcoa Corporation	226	1,137	104	307
Net change in unrecognized gains/losses on cash flow hedges, Noncontrolling interest		1		2
Net change in unrecognized gains/losses on cash flow hedges	226	1,138	104	309
Total Other comprehensive income (loss), net of tax, Alcoa Corporation	261	819	145	337
Total Other comprehensive income (loss), net of tax, Noncontrolling interest	9	(131)	24	(31)
Total Other comprehensive income (loss), net of tax	270	688	169	306
Comprehensive income (loss), Alcoa Corporation	159	1,368	(188)	1,355
Comprehensive income (loss), Noncontrolling interest	(10)	(6)	4	178
Comprehensive income (loss)	$ 149	$ 1,362	$ (184)	$ 1,533