v2.4.0.6
Impairments by Segment (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Impairment charges by segment, before-tax    
Impairments $ 2 $ 214
Canada [Member]
   
Impairment charges by segment, before-tax    
Impairments   213
Europe [Member]
   
Impairment charges by segment, before-tax    
Impairments   1
Asia Pacific and Middle East [Member]
   
Impairment charges by segment, before-tax    
Impairments $ 2