Restructuring And Other Charges (Pro Forma Restructuring And Other Charges By Reportable Segments, Pretax) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Restructuring and other charges	$ 34	$ 30	$ 40	$ 217
Alumina [Member]
Restructuring and other charges	25	1	26	13
Primary Metals [Member]
Restructuring and other charges		2	2	152
Flat-Rolled Products [Member]
Restructuring and other charges		(2)	2	(7)
Engineered Products and Solutions [Member]
Restructuring and other charges	3	18	3	22
Segment Total [Member]
Restructuring and other charges	28	19	33	180
Corporate [Member]
Restructuring and other charges	$ 6	$ 11	$ 7	$ 37