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Effect of One Percent Change in Assumptions at Which Retirement Liabilities Could be Effectively Settled (Detail) (CAD) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items] |
Effect on net benefit cost, before tax, One percent increase - Rate of return on plan assets | (60)imo_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseInRateOfReturnOnPlanAssetsOnNetBenefitCost
Effect on net benefit cost, before tax, One percent increase - Discount rate | (70)imo_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseInDiscountRateOnNetBenefitCost
Effect on benefit obligation, One percent increase - Discount rate | (1,100)imo_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseInDiscountRateOnBenefitObligation
Effect on net benefit cost, before tax, One percent increase- Rate of pay increases | 35 imo_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseInRateOfPayIncreasesOnNetBenefitCost
Effect on benefit obligation, One percent increase - Rate of pay increases | 190 imo_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseInRateOfPayIncreasesOnBenefitObligation
Effect on net benefit cost, before tax, One percent decrease - Rate of return on plan assets | 60 imo_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseInRateOfReturnOnPlanAssetsOnNetBenefitCost
Effect on net benefit cost, before tax, One percent decrease - Discount rate | 90 imo_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseInDiscountRateOnNetBenefitCost
Effect on benefit obligation, One percent decrease - Discount rate | 1,400 imo_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseInDiscountRateOnBenefitObligation
Effect on net benefit cost, before tax, One percent decrease- Rate of pay increases | (30)imo_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseInRateOfPayIncreasesOnPlanAssetsOnNetBenefitCost
Effect on benefit obligation, One percent decrease - Rate of pay increases | (170)imo_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseInRateOfPayIncreasesOnBenefitObligation

X
- Definition Defined benefit plan effect of one percentage point decrease in discount rate on benefit obligation + References No definition available. + Details
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Period Type: | duration

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- Definition Defined benefit plan effect of one percentage point decrease in discount rate on net benefit cost, before tax. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point decrease in rate of pay on net benefit obligation. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point decrease in rate of pay on net benefit cost, before tax. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point decrease in rate of return on plan assets on net benefit cost, before tax. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point increase in discount rate on benefit obligation + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point increase in discount rate on net benefit cost, before tax. + References No definition available. + Details
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Namespace Prefix: | imo_
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- Definition Defined benefit plan effect of one percentage point increase in rate of pay on net benefit obligation. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point increase in rate of pay on net benefit cost, before tax. + References No definition available. + Details
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- Definition Defined benefit plan effect of one percentage point increase in rate of return on plan assets on net benefit cost, before tax. + References No definition available. + Details
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