Pensions and Other Postretirement Benefits (Contributions to Multi-employer Plan) (Details) - Railroad Employees National Early Retirement Major Medical Benefit Plan [Member]	12 Months Ended
Dec. 31, 2022 CAD ($)	Dec. 31, 2021 CAD ($)	Dec. 31, 2020 CAD ($)
Multiemployer Plans [Line Items]
Contributions to multi-employer plan	$ 7,000,000	$ 10,000,000	$ 10,000,000
Multiemployer plan employer contribution rate per month	$ 109.49	$ 146.58
Number of retirees covered	263	328

Amount of cost for employer contribution to multiemployer plan. Multiemployer plan includes, but is not limited to, pension plan determined to be individually significant and insignificant and other postretirement benefit plan.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 35
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=29639808&loc=d3e29008-114946

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947

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