CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - CAD ($) $ in Millions		Total	Share capital	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Retained earnings	Cumulative Effect, Period of Adoption, Adjusted Balance	Cumulative Effect, Period of Adoption, Adjusted Balance Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact of accounting change		Accounting Standards Update 2016-13
Beginning balance at Dec. 31, 2018		$ 6,636	$ 2,002	$ 42	$ (2,043)	$ 6,635			$ 6,631	$ 6,630
Beginning balance (Accounting Standards Update 2016-02) at Dec. 31, 2018	[1]						$ (5)	$ (5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2,440				2,440
Other comprehensive (loss) income		(479)			(479)
Dividends declared		(434)				(434)
Effect of stock-based compensation expense		15		15
CP Common Shares repurchased		(1,140)	(54)			(1,086)
Shares issued under stock option plan		36	45	(9)
Ending balance at Dec. 31, 2019		7,069	1,993	48	(2,522)	7,550			$ 7,068	$ 7,549
Ending balance (Accounting Standards Update 2016-13) at Dec. 31, 2019	[2]						$ (1)	$ (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2,444				2,444
Other comprehensive (loss) income		(292)			(292)
Dividends declared		(479)				(479)
Effect of stock-based compensation expense		17		17
CP Common Shares repurchased		(1,477)	(58)			(1,419)
Shares issued under stock option plan		38	48	(10)
Ending balance at Dec. 31, 2020		7,319	1,983	55	(2,814)	8,095
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2,852				2,852
Other comprehensive (loss) income		711			711
Dividends declared		(556)				(556)
Effect of stock-based compensation expense		23		23
Shares issued for Kansas City Southern acquisition		23,456	23,461	(5)
Shares issued under stock option plan		24	31	(7)
Ending balance at Dec. 31, 2021		$ 33,829	$ 25,475	$ 66	$ (2,103)	$ 10,391

[1] Impact of the adoption of ASU 2016-02, Leases (Topic 842) on January 1, 2019.

[2] Impact of the adoption of ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) on January 1, 2020.