Net Other Operating (Income) Losses Analysis of income and expenses (Details) - CAD ($) $ in Millions		12 Months Ended
Jul. 20, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Analysis of income and expenses [Line Items]
Alberta Off-Coal Agreement	$ (40)	$ (40)	$ (40)	$ 0
Termination of the Sundance B and C PPAs		(157)	0	0
Mississauga cogeneration facility NUG Contract		0	(9)	(191)
Insurance recoveries		(7)	0	(3)
Restructuring provision		0	0	1
Net other operating expense (income)		$ (204)	$ (49)	$ (193)

The amount of expense relating to restructuring. Restructuring is a programme that is planned and controlled by management and materially changes either the scope of a business undertaken by an entity or the manner in which that business is conducted. Such programmes include: (a) the sale or termination of a line of business; (b) closure of business locations in a country or region or the relocation of activities from one country or region to another; (c) changes in management structure; and (d) fundamental reorganisations that have a material effect on the nature and focus of the entity's operations.

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The gains (losses) on disposals of investments.

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The amount of income recognised from the reimbursement of a claim as a result of the occurrence of an insured event covered by an insurance contract. [Refer: Types of insurance contracts [member]]

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The amount of operating income (expense) that the entity does not separately disclose in the same statement or note.

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[Line Items] for Analysis of income and expenses [Table]

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