Long-Term Debt - Additional Information (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about borrowings [Line Items]
Interest paid on long-term debt	$ 210	$ 229
Level 2 [Member]
Disclosure of detailed information about borrowings [Line Items]
Fair value of long-term debt	$ 5,439	$ 7,042

The amount of interest expense on borrowings. [Refer: Interest expense; Borrowings]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2021-03-24

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