INTERIM CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - CAD ($) shares in Millions, $ in Millions	Total	Parent	Share capital	Additional paid-in capital	Accumulated other comprehensive (loss) Income	Retained earnings	Non-controlling interest
Beginning balance (shares) at Dec. 31, 2021	929.7
Beginning balance at Dec. 31, 2021	$ 33,829	$ 33,829	$ 25,475	$ 66	$ (2,103)	$ 10,391	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,246	2,246				2,246
Other comprehensive income (loss)	2,236	2,236			2,236
Dividends declared	(531)	(531)				(531)
Effect of stock-based compensation expense	17	17		17
Shares issued for Kansas City Southern acquisition	$ (2)	(2)
Shares issued under stock option plan (shares)	0.4
Shares issued under stock option plan	$ 19	19	23	(4)
Ending balance (shares) at Sep. 30, 2022	930.1
Ending balance at Sep. 30, 2022	$ 37,814	37,814	25,498	77	133	12,106	0
Beginning balance (shares) at Jun. 30, 2022	930.0
Beginning balance at Jun. 30, 2022	$ 35,414	35,414	25,488	73	(1,539)	11,392	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	891	891				891
Other comprehensive income (loss)	1,672	1,672			1,672
Dividends declared	(177)	(177)				(177)
Effect of stock-based compensation expense	$ 5	5		5
Shares issued under stock option plan (shares)	0.1
Shares issued under stock option plan	$ 9	9	10	(1)
Ending balance (shares) at Sep. 30, 2022	930.1
Ending balance at Sep. 30, 2022	$ 37,814	37,814	25,498	77	133	12,106	0
Beginning balance (shares) at Dec. 31, 2022	930.5
Beginning balance at Dec. 31, 2022	$ 38,886	38,886	25,516	78	91	13,201	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,905	2,904				2,904	1
Other comprehensive income (loss)	(13)	(25)			(25)		12
Dividends declared	(530)	(530)				(530)
Effect of stock-based compensation expense	$ 24	24		24
Shares issued under stock option plan (shares)	1.2
Shares issued under stock option plan	$ 51	51	63	(12)
Non-controlling interest in connection with business acquisition	$ 932						932
Ending balance (shares) at Sep. 30, 2023	931.7
Ending balance at Sep. 30, 2023	$ 42,255	41,310	25,579	90	66	15,575	945
Beginning balance (shares) at Jun. 30, 2023	931.4
Beginning balance at Jun. 30, 2023	$ 41,004	40,079	25,563	88	(544)	14,972	925
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	780	780				780
Other comprehensive income (loss)	630	610			610		20
Dividends declared	(177)	(177)				(177)
Effect of stock-based compensation expense	$ 5	5		5
Shares issued under stock option plan (shares)	0.3
Shares issued under stock option plan	$ 13	13	16	(3)
Ending balance (shares) at Sep. 30, 2023	931.7
Ending balance at Sep. 30, 2023	$ 42,255	$ 41,310	$ 25,579	$ 90	$ 66	$ 15,575	$ 945