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Employee Defined Benefit Obligations - Summary of Quantitative Sensitivity Analyses Impact on Defined Benefit Obligation for Significant Assumptions (Detail) - CAD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Change in discount rate by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | $ (15.6) | $ (11.2)
Decrease | 17.0 | 11.8
Change in pre-retirement inflation rate by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 5.0 | 3.9
Decrease | (4.8) | (3.8)
Change in salary growth by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 0.9 | 0.5
Decrease | (0.8) | (0.5)
Change in pension increase assumption by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 8.4 | 6.4
Decrease | (8.1) | (6.1)
Increase of one year in the life expectancy [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | $ 9.4 | $ 6.0

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- Definition The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_145_a&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_145_a&doctype=Standard -URIDate 2018-03-16 + Details
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