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Inventory - Narrative (Details) - CAD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Inventories [Abstract] |  |
Write-down of product inventory | $ 4 | $ 13

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- Definition Inventories [Abstract] + References No definition available. + Details
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Period Type: | duration

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- Definition The amount recognised resulting from the write-down of inventories to net realisable value or reversals of those write-downs. [Refer: Inventories] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 98 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_98_a&doctype=Standard -URIDate 2019-03-27 + Details
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Balance Type: | debit
Period Type: | duration