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v2.4.1.9

Changes in Fair Value of Level 3 Assets (Detail) (CAD) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013
Mortgage Funds |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value at beginning | 1 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_MortgagesMember | 1 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_MortgagesMember
Net purchases/(sales) | (1)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements / us-gaap_InvestmentTypeAxis = us-gaap_MortgagesMember |
Fair value at ending |  | 1 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_MortgagesMember
Venture Capital |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value at beginning | 188 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember | 158 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember
Net realized gains/(losses) | (16)imo_FairValueMeasurementWithUnobservableInputsNetRealizedGainsLosses / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember | (17)imo_FairValueMeasurementWithUnobservableInputsNetRealizedGainsLosses / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember
Net unrealized gains/(losses) | 40 imo_FairValueMeasurementWithUnobservableInputsNetUnrealizedGainsLosses / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember | 44 imo_FairValueMeasurementWithUnobservableInputsNetUnrealizedGainsLosses / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember
Net purchases/(sales) | (1)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember | 3 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember
Fair value at ending | 211 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember | 188 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / us-gaap_InvestmentTypeAxis = us-gaap_VentureCapitalFundsMember

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- Definition Fair value measurement with unobservable inputs net unrealized gains losses. + References No definition available. + Details
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- Definition Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph c -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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