Statement of Consolidated Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
NET LOSS ATTRIBUTABLE TO ALCOA CORPORATION	$ (252)	$ (231)
Net income, Noncontrolling interest	(55)	(1)
Net (loss) income	(307)	(232)
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits, Alcoa Corporation	9	4
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits, Noncontrolling interest	1	0
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits	10	4
Foreign currency translation adjustments, Alcoa Corporation	(122)	2
Foreign currency translation adjustments, Noncontrolling interest	(54)	15
Foreign currency translation adjustments	(176)	17
Net change in unrecognized gains/losses on cash flow hedges, Alcoa Corporation	130	(122)
Net change in unrecognized gains/losses on cash flow hedges	130	(122)
Total Other comprehensive income (loss), net of tax, Alcoa Corporation	17	(116)
Total Other comprehensive income (loss), net of tax, Noncontrolling interest	(53)	15
Total Other comprehensive income (loss), net of tax	(36)	(101)
Comprehensive (loss) income , Alcoa Corporation	(235)	(347)
Comprehensive (loss) income , Noncontrolling interest	(108)	14
Comprehensive (loss) income	$ (343)	$ (333)