CONSOLIDATED STATEMENTS OF EARNINGS - CAD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating revenues
Total operating revenues (Note 4)	$ 12,352	$ 11,598	$ 13,263	$ 12,856	$ 11,562	$ 11,345	$ 10,745	$ 12,726	$ 50,069	$ 46,378	$ 44,378
Operating expenses
Operating and administrative									6,991	6,792	6,442
Depreciation and amortization									3,391	3,246	3,163
Impairment of long-lived assets (Note 8 and Note 11)									423	1,104	4,463
Impairment of goodwill (Note 8 and Note 16)									0	1,019	102
Total operating expenses									41,809	41,562	42,807
Operating income	1,768	1,588	2,285	2,619	1,513	854	1,571	878	8,260	4,816	1,571
Income from equity investments (Note 13)									1,503	1,509	1,102
Other income/(expense)
Net foreign currency gain/(loss)									477	(522)	237
Gain/(loss) on dispositions									(300)	(46)	16
Other									258	516	199
Interest expense (Note 18)									(2,663)	(2,703)	(2,556)
Earnings before income taxes									7,535	3,570	569
Income tax recovery/(expense) (Note 25)									(1,708)	(237)	2,697
Earnings	914	1,060	1,830	2,023	1,283	213	1,327	510	5,827	3,333	3,266
Earnings attributable to noncontrolling interests and redeemable noncontrolling interests									(122)	(451)	(407)
Earnings attributable to controlling interests	842	1,045	1,832	1,986	1,184	4	1,160	534	5,705	2,882	2,859
Preference share dividends									(383)	(367)	(330)
Earnings attributable to common shareholders	$ 746	$ 949	$ 1,736	$ 1,891	$ 1,089	$ (90)	$ 1,071	$ 445	$ 5,322	$ 2,515	$ 2,529
Earnings per common share attributable to common shareholders (in CAD per share)	$ 0.37	$ 0.47	$ 0.86	$ 0.94	$ 0.60	$ (0.05)	$ 0.63	$ 0.26	$ 2.64	$ 1.46	$ 1.66
Diluted earnings per common share attributable to common shareholders (in CAD per share)	$ 0.36	$ 0.47	$ 0.86	$ 0.94	$ 0.60	$ (0.05)	$ 0.63	$ 0.26	$ 2.63	$ 1.46	$ 1.65
Commodity sales
Operating revenues
Total operating revenues (Note 4)									$ 29,309	$ 27,660	$ 26,286
Operating expenses
Cost of goods and services sold									28,802	26,818	26,065
Gas distribution revenue
Operating revenues
Total operating revenues (Note 4)									4,205	4,360	4,215
Operating expenses
Cost of goods and services sold									2,202	2,583	2,572
Transportation and other services revenues
Operating revenues
Total operating revenues (Note 4)									$ 16,555	$ 14,358	$ 13,877