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Amount of accumulated benefit obligation (assets) for defined benefit pension plan with plan assets in excess of projected benefit obligation.

No definition available.

Name:	cp_DefinedBenefitPlanPensionPlanwithPlanAssetsinExcessofProjectedBenefitObligationAccumulatedPlanAssets
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Amount of plan asset for defined benefit pension plan with plan assets in excess of projected benefit obligation.

No definition available.

Name:	cp_DefinedBenefitPlanPensionPlanwithPlanAssetsinExcessofProjectedBenefitObligationPlanAssets
Namespace Prefix:	cp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
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Data Type:	xbrli:stringItemType
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Amount of accumulated benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

Name:	us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of projected benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.