XML 18 R1.htm IDEA: XBRL DOCUMENT v2.3.0.15
Document And Entity Information
9 Months Ended
Sep. 30, 2011
Oct. 14, 2011
Document And Entity Information  
Document Type10-Q 
Amendment Flagfalse 
Document Period End DateSep. 30, 2011
Document Fiscal Year Focus2011 
Document Fiscal Period FocusQ3 
Trading Symbolaa 
Entity Registrant NameALCOA INC 
Entity Central Index Key0000004281 
Current Fiscal Year End Date--12-31 
Entity Filer CategoryLarge Accelerated Filer 
Entity Common Stock, Shares Outstanding 1,064,303,727