INTERIM CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 618	$ 622	$ 1,776	$ 1,406
Net (loss) gain in foreign currency translation adjustments, net of hedging activities	(8)	12	23	(24)
Change in derivatives designated as cash flow hedges	2	1	8	36
Change in pension and post-retirement defined benefit plans	20	28	61	86
Other comprehensive income before income taxes	14	41	92	98
Income tax recovery (expense) on above items	3	(22)	(41)	(11)
Other comprehensive income (loss)	17	19	51	87
Comprehensive income	$ 635	$ 641	$ 1,827	$ 1,493