Capital Instruments - Additional Information (Detail) - CAD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Level 2 [Member]
Fair value of capital instruments [line items]
Capital instruments	$ 0	$ 7,333

The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 25
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_25&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_FinancialLiabilitiesAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant