INTERIM CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 472	$ 598	$ 2,320	$ 1,642
Net (loss) gain in foreign currency translation adjustments, net of hedging activities	(17)	16	3	(18)
Change in derivatives designated as cash flow hedges	141	3	69	6
Change in pension and post-retirement defined benefit plans	53	44	158	134
Other comprehensive income before income taxes	177	63	230	122
Income tax expense on above items	(29)	(29)	(59)	(16)
Other comprehensive income	148	34	171	106
Comprehensive income	$ 620	$ 632	$ 2,491	$ 1,748