v3.7.0.1
Employee Benefit Plans (Severances) (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 29, 2017
Supplemental Unemployment Benefits [Line Items]      
Foreign currency translation adjustments $ 184 $ 1,183  
Foster Creek Christina Lake (FCCL) and western Canada gas properties [Member]      
Supplemental Unemployment Benefits [Line Items]      
Severance Accrual, Ending Balance 39    
Foster Creek Christina Lake (FCCL) [Member]      
Supplemental Unemployment Benefits [Line Items]      
Investment Owned Percent Of Net Assets     50.00%
Employee Severance      
Supplemental Unemployment Benefits [Line Items]      
Severance Accrual, Beginning Balance 80    
Severance accrual current period change 39    
Payments For Postemployment Benefits (45)    
Foreign currency translation adjustments (1)    
Severance Accrual, Ending Balance 73    
Short term portion of severance accrual $ 48