Schedule II - Valuation and Qualifying Accounts (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accruals for personal injury and other claims provision
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance at January 1	$ 123	$ 126	$ 141
Additions charged to expenses	101	114	105
Payments and other reductions	(94)	(117)	(119)
Impact of FX	2	0	(1)
Ending balance at December 31	132	123	126
Environmental liabilities
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance at January 1	79	80	77
Additions charged to expenses	8	10	10
Payments and other reductions	(8)	(10)	(6)
Impact of FX	4	(1)	(1)
Ending balance at December 31	$ 83	$ 79	$ 80