Restructuring and Other Charges, Net - Schedule of Restructuring and Other Charges, Net by Reportable Segments, Pretax (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	$ 125	$ 7
Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	126	15
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	(1)	(8)
Bauxite [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	58
Aluminum Segment [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges, net	$ 68	$ 15