Severance, acquisition and other costs (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Analysis of income and expense [abstract]
Severance	$ (79)	$ (87)
Acquisition and other	(111)	(48)
Total severance, acquisition and other costs	$ (190)	$ (135)

Termination Benefits Expense, Acquisition-Related Costs, And Other Costs

No definition available.

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- Definition

The amount of acquisition-related costs recognised as an expense for transactions that are recognised separately from the acquisition of assets and the assumption of liabilities in business combinations. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2017-01-01
-Paragraph B64
-Subparagraph m
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2017-03-01&anchor=para_B64_m&doctype=Appendix&seq=2
-URIDate 2017-03-09

+ Details

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- References

No definition available.

+ Details

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- Definition

The amount of expense in relation to termination benefits. Termination benefits are employee benefits provided in exchange for the termination of an employee's employment as a result of either: (a) an entity's decision to terminate an employee's employment before the normal retirement date; or (b) an employee's decision to accept an offer of benefits in exchange for the termination of employment. [Refer: Employee benefits expense]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 171
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_171&doctype=Standard
-URIDate 2017-03-09

+ Details

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