Decommissioning Liabilities - Summary of Decommissioning Provision (Detail) $ in Millions	6 Months Ended
Jun. 30, 2019 CAD ($)
Provision For Decommissioning Restoration And Rehabilitation Costs [Abstract]
Beginning balance	$ 875
Liabilities Incurred	5
Liabilities Settled	(20)
Change in Discount Rate	310
Unwinding of Discount on Decommissioning Liabilities (Note 4)	28
Foreign Currency Translation	(1)
Ending balance	$ 1,197

Increase decrease through foreign currency translation.

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- Definition

The increase (decrease) in other provisions resulting from a change in discount rate. [Refer: Other provisions]

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The increase in other provisions through adjustments arising from the passage of time. [Refer: Other provisions]

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The amount recognised for new other provisions. [Refer: Other provisions]

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- Definition

The amount of provision for costs related to decommissioning, restoration and rehabilitation. [Refer: Other provisions]

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The amount used (ie incurrent and charged against the provision) for other provisions. [Refer: Other provisions]

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