Accounts Receivable (Details) - CAD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Accounts receivable
Gross accounts receivable	$ 1,185	$ 1,325
Allowance for credit losses	(21)	(25)
Net accounts receivable	1,164	1,300
Freight [Member]
Accounts receivable
Gross accounts receivable	966	1,051
Non-freight [Member]
Accounts receivable
Gross accounts receivable	$ 219	$ 274

Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483467/210-10-45-1

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Balance Type:	debit
Period Type:	instant