Final repayment of principal amount.

No definition available.

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- Definition

Amount of long-term debt due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

+ References

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Period Type:	instant

- Definition

Amount of assets pledged to secure a debt instrument.

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Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

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Balance Type:	credit
Period Type:	instant

- Definition

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

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- 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.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- 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.

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- Definition

Gross amount of debt extinguished.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of right-of-use asset from finance lease.

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Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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- Definition

The cash inflow associated with security instrument that either represents a creditor or an ownership relationship with the holder of the investment security with a maturity of beyond one year or normal operating cycle, if longer. Includes proceeds from (a) debt, (b) capital lease obligations, (c) mandatory redeemable capital securities, and (d) any combination of (a), (b), or (c).

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Debt - Components of Long-term Debt - (Narrative) (Details) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020 CAD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	$ 958		$ 397		$ 638
Finance lease, ROU asset	171		$ 177
7.250% 10-year Notes
Debt Instrument [Line Items]
Interest rate			7.25%			7.25%
Debt instrument, Term			10 years	10 years
Extinguishment of debt, Amount			$ 471	$ 350
2.050% 10-year Notes
Debt Instrument [Line Items]
Debt instrument, Face amount	$ 500
Interest rate	2.05%
Debt instrument, Term	10 years	10 years
Maturity date	Mar. 05, 2030	Mar. 05, 2030
Proceeds from issuance of debt	$ 662	$ 495
3.050% 30-year Notes
Debt Instrument [Line Items]
Debt instrument, Face amount	$ 300
Interest rate	3.05%
Debt instrument, Term	30 years	30 years
Maturity date	Mar. 09, 2050	Mar. 09, 2050
Proceeds from issuance of debt	$ 296
3.150% 10-year Notes
Debt Instrument [Line Items]
Debt instrument, Face amount			$ 400
Interest rate	3.15%		3.15%			3.15%
Debt instrument, Term			10 years	10 years
Maturity date	Mar. 13, 2029	Mar. 13, 2029	Mar. 13, 2029	Mar. 13, 2029
Proceeds from issuance of debt	$ 397
8.000% 5-year Promissory Notes
Debt Instrument [Line Items]
Interest rate	8.00%		8.00%			8.00%
Debt instrument, Term			5 years	5 years
Assumed obligations of CMQ Canada from business combination			$ 11			$ 8
5.41% Senior Secured Notes
Debt Instrument [Line Items]
Interest rate	5.41%		5.41%			5.41%
Maturity date	Mar. 03, 2024	Mar. 03, 2024
Value of locomotive units used as collateral	$ 97
Final repayment of principal amount		$ 44
6.91% Secured Equipment Notes
Debt Instrument [Line Items]
Interest rate	6.91%		6.91%			6.91%
Maturity date	Oct. 01, 2024	Oct. 01, 2024
Value of locomotive units used as collateral	$ 54
Final repayment of principal amount	$ 11
7.49% Equipment Trust Certificates
Debt Instrument [Line Items]
Interest rate	7.49%		7.49%			7.49%
Maturity date	Jan. 15, 2021	Jan. 15, 2021
Value of locomotive units used as collateral	$ 91
Final repayment of principal amount		$ 11