v2.4.0.8
Impairments by Segment (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Impairment charges by segment, before-tax        
Impairments $ 28 $ 82 $ 30 $ 296
Canada [Member]
       
Impairment charges by segment, before-tax        
Impairments     0 213
Europe [Member]
       
Impairment charges by segment, before-tax        
Impairments 28 78 28 79
Asia Pacific and Middle East [Member]
       
Impairment charges by segment, before-tax        
Impairments   $ 4 $ 2 $ 4