INTERIM CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 598	$ 618	$ 1,642	$ 1,776
Net gain (loss) in foreign currency translation adjustments, net of hedging activities	16	(8)	(18)	23
Change in derivatives designated as cash flow hedges	3	2	6	8
Change in pension and post-retirement defined benefit plans	44	20	134	61
Other comprehensive income before income taxes	63	14	122	92
Income tax (expense) recovery on above items	(29)	3	(16)	(41)
Other comprehensive income	34	17	106	51
Comprehensive income	$ 632	$ 635	$ 1,748	$ 1,827