Revenues - Disaggregation of Revenue (Details) - CAD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 2,029	$ 1,752
Leasing revenues	14	15
Total revenues	2,043	1,767
Freight
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,000	1,726
Total revenues	2,000	1,726
Grain
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	418	380
Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	150	158
Potash
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	112	114
Fertilizers and sulphur
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	70	57
Forest products
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	78	73
Energy, chemicals and plastics
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	491	315
Metals, minerals and consumer products
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	189	173
Automotive
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	87	76
Intermodal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	405	380
Non-freight excluding leasing revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 29	$ 26

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.

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Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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