CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - CAD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Earnings	$ 510	$ 945
Other comprehensive income/(loss), net of tax
Change in unrealized gain/(loss) on cash flow hedges	66	(2)
Change in unrealized gain/(loss) on net investment hedges	(184)	49
Other comprehensive income from equity investees	14	6
Reclassification to earnings of loss on cash flow hedges	37	41
Reclassification to earnings of pension and other postretirement benefits (OPEB) amounts	(39)	4
Foreign currency translation adjustments	1,579	432
Other comprehensive income, net of tax	1,473	530
Comprehensive income	1,983	1,475
Comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interests	(147)	(374)
Comprehensive income attributable to controlling interests	1,836	1,101
Preference share dividends	(89)	(83)
Comprehensive income attributable to common shareholders	$ 1,747	$ 1,018