Derivatives (Narrative) (Details) gal in Millions, CAD in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015 CAD	Sep. 30, 2015 CAD gal
Forward Contracts [Member]
Derivative [Line Items]
Foreign currency contract settlement amount (in Canadian dollars) \| CAD	CAD 221	CAD 221
Diesel swap \| Fixed price swap contracts
Derivative [Line Items]
Fixed price swap contract (in gallons)		9.5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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