INTERIM CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 724	$ 436	$ 1,158	$ 784
Net gain (loss) in foreign currency translation adjustments, net of hedging activities	15	(16)	31	(36)
Change in derivatives designated as cash flow hedges	4	14	6	35
Change in pension and post-retirement defined benefit plans	21	29	41	58
Other comprehensive income before income taxes	40	27	78	57
Income tax (expense) recovery on above items	(22)	5	(44)	11
Other comprehensive income (loss)	18	32	34	68
Comprehensive income	$ 742	$ 468	$ 1,192	$ 852