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
Beginning balance (shares) at Dec. 31, 2020	666.3
Beginning balance at Dec. 31, 2020	$ 7,319	$ 1,983	$ 55	$ (2,814)	$ 8,095
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	602	0	0	0	602
Other comprehensive income	58	0	0	58	0
Dividends declared	(126)	0	0	0	(126)
Effect of stock-based compensation expense	$ 5	0	5	0	0
Shares issued under stock option plan (shares)	0.3
Shares issued under stock option plan	$ 8	10	(2)	0	0
Ending balance (shares) at Mar. 31, 2021	666.6
Ending balance at Mar. 31, 2021	$ 7,866	1,993	58	(2,756)	8,571
Beginning balance (shares) at Dec. 31, 2021	929.7
Beginning balance at Dec. 31, 2021	$ 33,829	25,475	66	(2,103)	10,391
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	590	0	0	0	590
Other comprehensive income	(270)	0	0	(270)	0
Dividends declared	(177)	0	0	0	(177)
Effect of stock-based compensation expense	7	0	7	0	0
Stock Issued During Period, Value, Acquisitions	$ (2)	0	(2)	0	0
Shares issued under stock option plan (shares)	0.2
Shares issued under stock option plan	$ 8	11	(3)	0	0
Ending balance (shares) at Mar. 31, 2022	929.9
Ending balance at Mar. 31, 2022	$ 33,985	$ 25,486	$ 68	$ (2,373)	$ 10,804