Summary Of Significant Accounting Policies (Weighted-Average Useful Lives Of Software And Other Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2011
Computer Software [Member] | Alumina [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	10
Computer Software [Member] | Primary Metals [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	10
Computer Software [Member] | Flat-Rolled Products [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	9
Computer Software [Member] | Engineered Products And Solutions [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	9
Other Intangible Assets [Member] | Primary Metals [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	40
Other Intangible Assets [Member] | Flat-Rolled Products [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	10
Other Intangible Assets [Member] | Engineered Products And Solutions [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful lives of other intangible assets	17