Cash Consideration Paid For Debt Exchange

No definition available.

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

- Definition

Debt Instrument, Number Of Series Of Notes

+ References

No definition available.

+ Details

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Namespace Prefix:	cp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Principal Amount Exchanged

+ References

No definition available.

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(2))
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-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a)(3))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
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+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
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-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
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

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt premium.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28541-108399

+ Details

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

- Definition

Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

No definition available.

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

Name:	us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of cash outflow (inflow) through acquisition (sale) of short-term held-to-maturity securities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
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-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585

+ Details

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

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentDebtSecuritiesMember
Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cp_KansasCitySouthernMember
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=cp_SecondAmendedAndRestatedCreditAgreementMember
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=cp_NotesDueInSeptember2026Member
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=cp_NotesDueInSeptember2023Member
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Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
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Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
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Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=cp_FourPointFourFivePercentTwelvePointFiveYearNotesMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cp_KCSNotesDueNovember2023Member
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Name:	us-gaap_DebtInstrumentAxis=cp_A30010YearSeniorNotesMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
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- Details

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Debt - Narrative (Details)				3 Months Ended		9 Months Ended
Debt - Narrative (Details)	May 15, 2023 USD ($)	May 11, 2023 USD ($)	Apr. 19, 2023 USD ($) series	Sep. 30, 2023 CAD ($)	Sep. 30, 2022 CAD ($)	Sep. 30, 2023 CAD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 CAD ($)	Sep. 30, 2023 USD ($)	Jul. 12, 2023 USD ($)	Jul. 11, 2023 USD ($)	May 10, 2023 USD ($)	Apr. 24, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Commercial paper borrowings														$ 0
Number of series of notes included in debt exchange \| series			7
Acquisition-related costs				$ 0		$ 12,000,000
Repayments of long-term debt						600,000,000	$ 447,000,000
Investment in government securities				0	$ 0	267,000,000	198,000,000	$ 0
US Government Debt Securities
Debt Instrument [Line Items]
Non-callable government securities													$ 647,000,000
KCS
Debt Instrument [Line Items]
Acquisition-related costs				$ 24,000,000	$ 18,000,000	158,000,000		$ 57,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity (up to)												$ 1,300,000,000
Revolving Credit Facility \| Second Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity (up to)		$ 2,200,000,000							$ 2,200,000,000
Revolving Credit Facility \| Notes Due in September 2026
Debt Instrument [Line Items]
Note term		5 years
Revolving Credit Facility \| Notes Due in September 2023
Debt Instrument [Line Items]
Note term		2 years
Senior Notes
Debt Instrument [Line Items]
Cash consideration paid for debt exchange			$ 1.00
Premium on debt exchange			30
Principal and interest outstanding			3,014,000,000
Senior Notes \| Early participation date
Debt Instrument [Line Items]
Principal amount exchanged			1,000
Senior Notes \| After the early participation date, before the expiration date
Debt Instrument [Line Items]
Principal amount exchanged			$ 970
Senior Notes \| 4.500% 12.5-year Notes
Debt Instrument [Line Items]
Repayment of note						$ 479,000,000	$ 350,000,000
Interest rate				4.45%		4.45%			4.45%
Note term						12 years 6 months	12 years 6 months
Senior Notes \| KCS Notes Due in November 2023
Debt Instrument [Line Items]
Interest rate				3.85%		3.85%			3.85%
Principal and interest outstanding									$ 202,000,000
Senior Notes \| 3.00% Senior Notes
Debt Instrument [Line Items]
Repayment of note	$ 439,000,000
Interest rate	3.00%
Senior Notes \| 3.00% 10-Year Senior Notes
Debt Instrument [Line Items]
Repayment of note						$ 592,000,000	$ 439,000,000
Interest rate				3.00%		3.00%			3.00%
Note term						10 years	10 years
Unsecured Debt \| Commercial Paper
Debt Instrument [Line Items]
Maximum borrowing capacity (up to)									$ 1,500,000,000	$ 1,500,000,000	$ 1,000,000,000
Commercial paper borrowings				$ 406,000,000		$ 406,000,000			$ 300,000,000
Weighted average interest rate				5.54%		5.54%			5.54%