CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Earnings	$ 1,327	$ 1,241	$ 1,837	$ 2,186
Other comprehensive income/(loss), net of tax
Change in unrealized gain/(loss) on cash flow hedges	27	(85)	93	(87)
Change in unrealized gain/(loss) on net investment hedges	(99)	171	(283)	220
Other comprehensive income from equity investees	5	2	19	8
Reclassification to earnings of loss on cash flow hedges	36	66	73	107
Reclassification to earnings of pension and other postretirement benefits (OPEB) amounts	62	3	23	7
Foreign currency translation adjustments	1,047	(1,443)	2,626	(1,011)
Other comprehensive income/(loss), net of tax	1,078	(1,286)	2,551	(756)
Comprehensive income/(loss)	2,405	(45)	4,388	1,430
Comprehensive (income)/loss attributable to noncontrolling interests and redeemable noncontrolling interests	(297)	15	(444)	(359)
Comprehensive income/(loss) attributable to controlling interests	2,108	(30)	3,944	1,071
Preference share dividends	(89)	(81)	(178)	(164)
Comprehensive income/(loss) attributable to common shareholders	$ 2,019	$ (111)	$ 3,766	$ 907