Commitments (Narrative) (Details) - Scenario, Forecast [Member] - Natural Gas [Member]	Dec. 31, 2016 MMcf / D CAD / Mcf	Dec. 31, 2015 MMcf / D CAD / Mcf
2015 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Sales contract price		4.13
Notional amount, per day | MMcf / D		65
2016 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Sales contract price	3.19	3.19
Notional amount, per day | MMcf / D	59