Business Combination, Miles Of Rail Lines Acquired

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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 after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Business combination - Narrative (Details) $ in Millions		12 Months Ended
Business combination - Narrative (Details) $ in Millions	Dec. 30, 2019 CAD ($) mi	Dec. 31, 2019 CAD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2017 CAD ($)
Business Acquisition [Line Items]
Investment in Central Maine & Quebec Railway		$ 174
Goodwill		194	$ 194	$ 178
Rail investments accounted for on an equity basis		166	160
CMQ
Business Acquisition [Line Items]
Investment in Central Maine & Quebec Railway	$ 174	174	0	$ 0
Goodwill	$ 10
Rail investments accounted for on an equity basis		$ 127	$ 0
Canada \| CMQ
Business Acquisition [Line Items]
Miles of rail lines acquired \| mi	237
United States \| CMQ
Business Acquisition [Line Items]
Miles of rail lines acquired \| mi	244