Contingent Payment - Additional Information (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Contingent Liabilities In Business Combination [Abstract]
Contingent payable	$ 124	$ 17

The amount of contingent liabilities recognised in a business combination that were settled. [Refer: Contingent liabilities recognised in business combination]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2017-01-01
-Paragraph B67
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2017-03-01&anchor=para_B67_c&doctype=Appendix&seq=2
-URIDate 2017-03-09

Name:	ifrs-full_SettledLiabilitiesContingentLiabilitiesRecognisedInBusinessCombination
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration