Restructuring and Other Charges - Schedule of Restructuring and Other Charges by Reportable Segments, Pretax (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 244	$ 15	$ 251	$ 25
Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	120	2	126	11
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	124	13	125	14
Alumina [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		1		1
Primary Metals [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	94	1	94	6
Global Rolled Products [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	7		10	1
Engineered Products and Solutions [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 19		$ 22	$ 3