Insurance Contract Liabilities and Reinsurance Assets - Summary of Components of Gross and Net Insurance Contract Liabilities (Parenthetical) (Detail) - CAD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure of insurance contract liabilities and reinsurance assets [abstract]
Reinsurance assets for investment contract liabilities	$ 67	$ 93

The amount of reinsurance contracts held that are liabilities. [Refer: Liabilities; Reinsurance contracts held [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2021-01-01
-Name IFRS
-Number 17
-IssueDate 2020-01-01
-Paragraph 78
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_78_d&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2021-01-01
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 54
-Subparagraph ma
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_ma&doctype=Standard
-URIDate 2020-01-01

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