CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - CAD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Earnings	$ 213	$ 1,015	$ 2,050	$ 3,201
Other comprehensive income/(loss), net of tax
Change in unrealized gain on cash flow hedges	57	97	150	10
Change in unrealized gain/(loss) on net investment hedges	83	285	(200)	505
Other comprehensive income from equity investees	(1)	1	18	9
Reclassification to earnings of (gain)/loss on cash flow hedges	31	(14)	104	93
Reclassification to earnings of pension and other postretirement benefits (OPEB) amounts	5	6	28	13
Foreign currency translation adjustments	(989)	(2,057)	1,637	(3,068)
Other comprehensive income/(loss), net of tax	(814)	(1,682)	1,737	(2,438)
Comprehensive income/(loss)	(601)	(667)	3,787	763
Comprehensive (income)/loss attributable to noncontrolling interests and redeemable noncontrolling interests	(102)	155	(546)	(204)
Comprehensive income/(loss) attributable to controlling interests	(703)	(512)	3,241	559
Preference share dividends	(94)	(82)	(272)	(246)
Comprehensive income/(loss) attributable to common shareholders	$ (797)	$ (594)	$ 2,969	$ 313