INTANGIBLE AND OTHER ASSETS (Details) - CAD CAD in Millions	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Capital projects in development	CAD 596	CAD 2,094
Deferred income tax assets (Note 16)	255	313
Employee post-retirement benefits (Note 22)	193	189
Fair value of derivative contracts (Note 23)	73	133
Other	306	218
Intangible and other assets	CAD 1,423	CAD 2,947

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards classified as noncurrent.

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Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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Amount of noncurrent assets classified as other.

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