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v3.19.3.a.u2

Change in Projected Benefit Obligation (Detail) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Pension benefits |  |  |
Schedule Of Defined Benefit Plans Disclosures [Line Items] |  |  |
Projected benefit obligation at January 1 | $ 8,359 | $ 8,785 |
Current service cost | 228 | 239 | $ 217
Interest cost | 324 | 302 | 313
Actuarial loss (gain) | 1,053 | (498) |
Amendments | 283 |  |
Benefits paid | (461) | (469) |
Projected benefit obligation at December 31 | 9,786 | 8,359 | 8,785
Accumulated benefit obligation at December 31 | 8,814 | 7,661 |
Other postretirement benefits |  |  |
Schedule Of Defined Benefit Plans Disclosures [Line Items] |  |  |
Projected benefit obligation at January 1 | 582 | 670 |
Current service cost | 16 | 17 | 16
Interest cost | 20 | 22 | 23
Actuarial loss (gain) | 99 | (101) |
Benefits paid | (24) | (26) |
Projected benefit obligation at December 31 | $ 693 | $ 582 | $ 670

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- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Definition Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(6) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964 + Details
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