v2.4.0.6
Document and Entity Information (USD $)
In Billions, except Share data, unless otherwise specified
9 Months Ended
Sep. 30, 2011
Oct. 24, 2011
Jun. 30, 2010
Document and Entity Information [Abstract]      
Entity Registrant Name Kaiser Aluminum Corp    
Entity Central Index Key 0000811596    
Document Type 10-Q    
Document Period End Date Sep. 30, 2011    
Amendment Flag false    
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q3    
Current Fiscal Year End Date --12-31    
Entity Well Known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 0.5
Entity Common Stock, Shares Outstanding   19,294,649