SEGMENTED INFORMATION (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segmented Information
Revenues	$ 10,948	$ 7,956	$ 23,085	$ 19,969
Commodity and gas distribution costs	(6,719)	(3,108)	(13,867)	(11,126)
Operating and administrative	(1,484)	(1,801)	(3,043)	(3,401)
Income from equity investments	352	327	747	490
Impairment of equity investments	0	0	0	(1,736)
Other income/(expense)	241	624	502	(523)
Earnings/(loss) before interest, income taxes, and depreciation and amortization	3,338	3,998	7,424	3,673
Depreciation and amortization	(929)	(949)	(1,861)	(1,831)
Interest expense	(618)	(681)	(1,275)	(1,387)
Income tax expense	(270)	(591)	(753)	(42)
Earnings	1,521	1,777	3,535	413
Capital expenditures	1,425	1,221	3,499	2,379
Eliminations and Other
Segmented Information
Revenues	(157)	(194)	(306)	(305)
Commodity and gas distribution costs	154	168	320	272
Operating and administrative	(99)	(246)	(76)	(147)
Income from equity investments	0	0	0	0
Impairment of equity investments				0
Other income/(expense)	194	533	374	(525)
Earnings/(loss) before interest, income taxes, and depreciation and amortization	92	261	312	(705)
Capital expenditures	9	19	21	41
Liquids Pipelines | Business segments
Segmented Information
Revenues	2,547	2,945	5,246	4,479
Commodity and gas distribution costs	(7)	(1)	(10)	(8)
Operating and administrative	(673)	(782)	(1,492)	(1,647)
Income from equity investments	180	148	334	345
Impairment of equity investments				0
Other income/(expense)	(3)	30	5	21
Earnings/(loss) before interest, income taxes, and depreciation and amortization	2,044	2,340	4,083	3,190
Capital expenditures	567	561	1,923	1,061
Gas Transmission and Midstream | Business segments
Segmented Information
Revenues	1,128	1,203	2,342	2,560
Commodity and gas distribution costs	0	0	0	0
Operating and administrative	(424)	(438)	(858)	(945)
Income from equity investments	132	168	314	93
Impairment of equity investments				(1,736)
Other income/(expense)	32	17	43	(76)
Earnings/(loss) before interest, income taxes, and depreciation and amortization	868	950	1,841	(104)
Capital expenditures	547	429	1,029	820
Gas Distribution and Storage | Business segments
Segmented Information
Revenues	953	903	2,776	2,585
Commodity and gas distribution costs	(299)	(254)	(1,257)	(1,126)
Operating and administrative	(242)	(269)	(514)	(518)
Income from equity investments	27	(8)	49	15
Impairment of equity investments				0
Other income/(expense)	19	11	38	31
Earnings/(loss) before interest, income taxes, and depreciation and amortization	458	383	1,092	987
Capital expenditures	300	204	519	426
Renewable Power Generation | Business segments
Segmented Information
Revenues	132	150	249	303
Commodity and gas distribution costs	0	0	0	0
Operating and administrative	(37)	(37)	(80)	(87)
Income from equity investments	13	21	50	37
Impairment of equity investments				0
Other income/(expense)	7	29	52	30
Earnings/(loss) before interest, income taxes, and depreciation and amortization	115	163	271	283
Capital expenditures	2	7	7	30
Energy Services | Business segments
Segmented Information
Revenues	6,345	2,949	12,778	10,347
Commodity and gas distribution costs	(6,567)	(3,021)	(12,920)	(10,264)
Operating and administrative	(9)	(29)	(23)	(57)
Income from equity investments	0	(2)	0	0
Impairment of equity investments				0
Other income/(expense)	(8)	4	(10)	(4)
Earnings/(loss) before interest, income taxes, and depreciation and amortization	(239)	(99)	(175)	22
Capital expenditures	$ 0	$ 1	$ 0	$ 1