INTERIM CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 1,246	$ 635	$ 1,848	$ 1,044
Net gain (loss) in foreign currency translation adjustments, net of hedging activities	10	31	20	(34)
Change in derivatives designated as cash flow hedges	(97)	1	(72)	3
Change in pension and post-retirement defined benefit plans	52	45	105	90
Other comprehensive (loss) income before income taxes	(35)	77	53	59
Income tax (expense) recovery on above items	0	(47)	(30)	13
Other comprehensive (loss) income	(35)	30	23	72
Comprehensive income	$ 1,211	$ 665	$ 1,871	$ 1,116