Supplementary Cash Flow Information - Summary of Supplementary Cash Flow Information (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Supplementary Cash Flow Information [Abstract]
Interest Paid	$ 381	$ 457	$ 564
Interest Received	5	12	19
Income Taxes Paid	$ 18	$ 17	$ 116

Disclosure of supplementary cash flow information abstract.

No definition available.

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- Definition

The cash flows from income taxes paid or refunded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 35
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-URIDate 2020-01-01

+ Details

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- Definition

The cash outflow for interest paid, classified as operating activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 31
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-URIDate 2020-01-01

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- Definition

The cash inflow from interest received, classified as operating activities.

+ References

+ Details

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