EARNINGS PER SHARE (TABLE)
 9 Months Ended
Sep. 30, 2012
Earnings Per Share Abstract  
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
##NEAR. EARNINGS PER SHARE
              
The following table summarizes the number of shares outstanding as well as our basic and diluted earnings per-share (in millions, except per share amounts):
             
    Three Months Ended   Nine Months Ended
    Sep. 30,   Sep. 30,
   2012 2011 2012 2011
Net earnings attributable to Owens Corning$ 44 $ 124 $ 37 $ 226
              
Weighted-average number of shares outstanding used for            
 basic earnings per share  117.9   121.7   119.8   123.2
Non-vested restricted and performance shares  0.6   0.6   0.5   0.6
Options to purchase common stock  0.3   0.3   0.3   0.4
Weighted-average number of shares outstanding and common           
 equivalent shares used for diluted earnings per share  118.8   122.6   120.6   124.2
              
Earnings per common share attributable to Owens Corning           
 common stockholders:           
 Basic$ 0.37 $ 1.02 $ 0.31 $ 1.83
 Diluted$ 0.37 $ 1.01 $ 0.31 $ 1.82