Restructuring and Other Charges, Net - Schedule of Restructuring and Other Charges, Net by Reportable Segments, Pretax (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 696	$ 1,128	$ 104
Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	55	185	59
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	641	943	45
Bauxite [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	58		1
Alumina [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	(85)	1	5
Aluminum Segment [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 82	$ 184	$ 53