CHANGES IN ACCOUNTING POLICIES (Details) - CAD CAD in Millions	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deficit	CAD (2,468)	CAD (716)
Property, plant and equipment, net	90,711	CAD 64,284
Difference between revenue guidance in effect before and after Topic 606 \| Accounting Standards Update 2014-09 \| Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deficit	120
Property, plant and equipment, net	130
Deferred revenue	CAD 120

Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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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.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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