Derivative Instruments, Open Long (Short) Positions (Details) (CAD) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Forwards | 2014
Derivative
Derivative, Notional Amount	40
Maturity of Foreign Currency Derivatives	Jul. 25, 2014
Crude Oil And Refined Products (in barrels) | Futures | Short | 2014
Derivative
Contract volumes	(8,946,000)
Crude Oil And Refined Products (in barrels) | Futures | Short | 2015
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | Futures | Short | 2016
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | Futures | Short | 2017
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | OTC Swaps | Long | 2014
Derivative
Contract volumes	2,100,000
Crude Oil And Refined Products (in barrels) | OTC Swaps | Long | 2015
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | OTC Swaps | Long | 2016
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | OTC Swaps | Long | 2017
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | Forwards | Short | 2014
Derivative
Contract volumes	(367,000)
Crude Oil And Refined Products (in barrels) | Forwards | Short | 2015
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | Forwards | Short | 2016
Derivative
Contract volumes	0
Crude Oil And Refined Products (in barrels) | Forwards | Short | 2017
Derivative
Contract volumes	0
Carbon Credit (in tons) | Futures | Long | 2014
Derivative
Contract, mass	0
Carbon Credit (in tons) | Futures | Long | 2015
Derivative
Contract, mass	0
Carbon Credit (in tons) | Futures | Long | 2016
Derivative
Contract, mass	1,000,000
Carbon Credit (in tons) | Futures | Long | 2017
Derivative
Contract, mass	1,000,000
Renewable Fuels And Blending Products (in gallons) | Futures | Long | 2014
Derivative
Contract volumes	68,250,000
Renewable Fuels And Blending Products (in gallons) | Futures | Long | 2015
Derivative
Contract volumes	0
Renewable Fuels And Blending Products (in gallons) | Futures | Long | 2016
Derivative
Contract volumes	0
Renewable Fuels And Blending Products (in gallons) | Futures | Long | 2017
Derivative
Contract volumes	0
Renewable Fuels And Blending Products (in gallons) | Futures | Short | 2014
Derivative
Contract volumes	0
Renewable Fuels And Blending Products (in gallons) | Futures | Short | 2015
Derivative
Contract volumes	(840,000)
Renewable Fuels And Blending Products (in gallons) | Futures | Short | 2016
Derivative
Contract volumes	0
Renewable Fuels And Blending Products (in gallons) | Futures | Short | 2017
Derivative
Contract volumes	0
Corn (in bushels) | Futures | Short | 2014
Derivative
Contract volumes	(6,015,000)
Corn (in bushels) | Futures | Short | 2015
Derivative
Contract volumes	0
Corn (in bushels) | Futures | Short | 2016
Derivative
Contract volumes	0
Corn (in bushels) | Futures | Short | 2017
Derivative
Contract volumes	0