The amount of funds to be distributed to those claiming derailment damages.

No definition available.

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Balance Type:	credit
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- Definition

Long term purchase commitment period beginning year.

+ References

No definition available.

+ Details

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- Definition

Long term purchase commitment period ending year.

+ References

No definition available.

+ Details

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- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
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-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

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- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Number of pending claims pertaining to a loss contingency.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

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

- Details

Name:	srt_LitigationCaseAxis=cp_LacMeganticRailAccidentMember
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Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=cp_ClaimedLossorDamagesDuetoDerailmentMember
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Name:	dei_LegalEntityAxis=cp_IrvingOilMember
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Name:	srt_CounterpartyNameAxis=cp_QuebecMinisterofSustainableDevelopmentandEnvironmentMember
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Balance Type:
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Name:	srt_CounterpartyNameAxis=cp_QuebecAttorneyGeneralMember
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Name:	srt_CounterpartyNameAxis=cp_InitialInsurerClaimantsMember
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Commitments and Contingencies - Narrative (Details) $ in Millions									12 Months Ended
	May 14, 2018 CAD ($) claim	Dec. 28, 2017 CAD ($)	Oct. 10, 2017 CAD ($)	Jul. 11, 2016 CAD ($) claim	Jul. 05, 2016 CAD ($)	Jul. 04, 2016 CAD ($) claim	Apr. 12, 2016 CAD ($)	Jul. 06, 2015 CAD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2017 CAD ($)	Dec. 31, 2016 CAD ($)
Commitments and Contingencies [Line Items]
Period for which future capital and operating expenditures are committed, beginning year									2019
Period for which future capital and operating expenditures are committed, end year									2032
Estimated future purchase commitment									$ 951
Total minimum lease payments									485
Expenses for operating leases									97	$ 104	$ 111
Lac-Megantic Rail Accident \| Claimed damages as a result of derailment
Commitments and Contingencies [Line Items]
Amount of fund to be distributed									440
Lac-Megantic Rail Accident \| Irving Oil [Member]
Commitments and Contingencies [Line Items]
Value of damages sought							$ 60
Lac-Megantic Rail Accident \| Quebec Minister of Sustainable Development, Environment, Wildlife and Parks
Commitments and Contingencies [Line Items]
Value of damages sought					$ 95
Lac-Megantic Rail Accident \| Quebec Attorney General
Commitments and Contingencies [Line Items]
Value of damages sought			$ 315					$ 409
Lac-Megantic Rail Accident \| Initial Insurer Claimants \| Subrogated insurance claim
Commitments and Contingencies [Line Items]
Value of damages sought		$ 14				$ 16
Number of subrogated insurers \| claim						8
Lac-Megantic Rail Accident \| Additional Insurer Claimants \| Subrogated insurance claim
Commitments and Contingencies [Line Items]
Value of damages sought				$ 3
Number of subrogated insurers \| claim				2
Lac-Megantic Rail Accident \| Plaintiff [Member]
Commitments and Contingencies [Line Items]
Value of damages sought	$ 5
Number of plaintiffs \| claim	48
Lac-Megantic Rail Accident \| The WD Trustee \| Damaged railcars loss recovery
Commitments and Contingencies [Line Items]
Value of damages sought							6
Lac-Megantic Rail Accident \| Montreal Maine and Atlantic Railway \| World Fuel Entities [Member]
Commitments and Contingencies [Line Items]
Value of damages sought							$ 110
Capital Expenditure [Member]
Commitments and Contingencies [Line Items]
Total future committed expenditure									586
Operating Expenditures [Member]
Commitments and Contingencies [Line Items]
Total future committed expenditure									$ 1,200