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Employee Future Benefits - Costs Recognized (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | $ 12 | $ 10 | $ 11
Administration expenses | 1 | 2 | 2
Defined benefit expense | 22 | 21 | 22
Defined contribution expense | 10 | 11 | 15
Net expense | 32 | 32 | 37
Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 12 | 10 |
Interest cost | 22 | 24 | 25
Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | (13) | (15) | (16)
Registered |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 9 | 7 | 7
Administration expenses | 1 | 2 | 2
Defined benefit expense | 15 | 14 | 14
Defined contribution expense | 10 | 11 | 15
Net expense | 25 | 25 | 29
Registered | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 9 | 7 |
Interest cost | 18 | 20 | 21
Registered | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | (13) | (15) | (16)
Supplemental |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 2 | 2 | 2
Administration expenses | 0 | 0 | 0
Defined benefit expense | 5 | 5 | 5
Defined contribution expense | 0 | 0 | 0
Net expense | 5 | 5 | 5
Supplemental | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 2 | 2 |
Interest cost | 3 | 3 | 3
Supplemental | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | 0 | 0 | 0
Other |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 1 | 1 | 2
Administration expenses | 0 | 0 | 0
Defined benefit expense | 2 | 2 | 3
Defined contribution expense | 0 | 0 | 0
Net expense | 2 | 2 | 3
Other | Defined benefit obligation |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Current service cost | 1 | 1 |
Interest cost | 1 | 1 | 1
Other | Plan assets |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |
Interest cost | $ 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 2017-01-01 -Paragraph 141 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_a&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + 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 2017-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_102&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 99 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_99&doctype=Standard -URIDate 2017-03-09 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 104 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_104&doctype=Standard -URIDate 2017-03-09 + 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 2017-01-01 -Paragraph 141 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_b&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The amount of post-employment benefit expense relating to defined benefit plans. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 5 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_5&doctype=Standard -URIDate 2017-03-09 + 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 2017-01-01 -Paragraph 53 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_53&doctype=Standard -URIDate 2017-03-09 + Details
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