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Employee Future Benefits - Costs Recognized (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | $ 6 | $ 8 | $ 10
Administration expenses | 1 | 1 | 2
Defined benefit expense | 6 | 15 | 19
Defined contribution expense | 8 | 9 | 9
Net expense | 14 | 24 | 28
Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | 14 | 20 | 23
Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | (8) | (12) | (13)
Curtailment and amendment gain | (7) | (2) | (3)
Registered |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 3 | 5 | 7
Administration expenses | 1 | 1 | 2
Defined benefit expense | 1 | 9 | 13
Defined contribution expense | 8 | 9 | 9
Net expense | 9 | 18 | 22
Registered | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 3 | 5 |
Interest cost | 12 | 16 | 19
Curtailment and amendment gain | (7) | (2) |
Registered | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | (8) | (11) | (12)
Curtailment and amendment gain | (7) | (2) | (3)
Supplemental Pension Plan |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 2 | 2 | 2
Administration expenses | 0 | 0 | 0
Defined benefit expense | 4 | 4 | 4
Defined contribution expense | 0 | 0 | 0
Net expense | 4 | 4 | 4
Supplemental Pension Plan | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 2 | 2 |
Interest cost | 2 | 3 | 3
Curtailment and amendment gain | 0 | 0 |
Supplemental Pension Plan | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | 0 | (1) | (1)
Curtailment and amendment gain | 0 | 0 | 0
Other |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 1 | 1 | 1
Administration expenses | 0 | 0 | 0
Defined benefit expense | 1 | 2 | 2
Defined contribution expense | 0 | 0 | 0
Net expense | 1 | 2 | 2
Other | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 1 | 1 |
Interest cost | 0 | 1 | 1
Curtailment and amendment gain | 0 | 0 |
Other | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | 0 | 0 | 0
Curtailment and amendment gain | $ 0 | $ 0 | $ 0

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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2021-01-01 -Paragraph 141 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_141_a&doctype=Standard -URIDate 2021-03-24 + Details
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- Definition The expense of all forms of consideration given by an entity in exchange for a service rendered by employees or for the termination of employment. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_102&doctype=Standard -URIDate 2021-03-24 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 99 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_99&doctype=Standard -URIDate 2021-03-24 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 104 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_104&doctype=Standard -URIDate 2021-03-24 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2021-01-01 -Paragraph 141 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_141_b&doctype=Standard -URIDate 2021-03-24 + Details
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- Definition The amount of post-employment benefit expense included in profit or loss relating to defined benefit plans. [Refer: Profit (loss); Defined benefit plans [member]] [Contrast: Increase (decrease) in net defined benefit liability (asset) resulting from expense (income) in profit or loss] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2021-01-01 -Paragraph 5 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_5&doctype=Standard -URIDate 2021-03-24 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2021-01-01 -Paragraph 135 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_135_b&doctype=Standard -URIDate 2021-03-24 + Details
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- Definition The amount of post-employment benefit expense relating to defined contribution plans. Defined contribution plans are post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2021-01-01 -Paragraph 53 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_53&doctype=Standard -URIDate 2021-03-24 + Details
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