INTERIM CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) - CAD ($) shares in Millions, $ in Millions	Total	Share capital	Additional paid-in capital	Accumulated other comprehensive loss	Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at January 1, 2020, as restated	$ 6,631	$ 2,002	$ 42	$ (2,043)	$ 6,630
Beginning balance (shares) at Dec. 31, 2018	140.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 434	0	0	0	434
Other comprehensive income	16	0	0	16	0
Dividends declared	(91)	0	0	0	(91)
Effect of stock-based compensation expense	$ 5	0	5	0	0
CP Common Shares repurchased (shares)	(0.7)
CP Common Shares repurchased	$ (185)	(10)	0	0	(175)
Shares issued under stock option plan (shares)	0.0
Shares issued under stock option plan	$ (4)	(5)	(1)	0	0
Ending balance (shares) at Mar. 31, 2019	139.8
Ending balance at Mar. 31, 2019	$ 6,814	1,997	46	(2,027)	6,798
Beginning balance (shares) at Dec. 31, 2019	137.0
Beginning balance at Dec. 31, 2019	$ 7,069	1,993	48	(2,522)	7,550
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	409	0	0	0	409
Other comprehensive income	42	0	0	42	0
Dividends declared	(112)	0	0	0	(112)
Effect of stock-based compensation expense	$ 5	0	5	0	0
CP Common Shares repurchased (shares)	(1.6)
CP Common Shares repurchased	$ (468)	(21)	0	0	(447)
Shares issued under stock option plan (shares)	0.2
Shares issued under stock option plan	$ (11)	(13)	(2)	0	0
Ending balance (shares) at Mar. 31, 2020	135.6
Ending balance at Mar. 31, 2020	$ 6,955	$ 1,985	$ 51	$ (2,480)	$ 7,399