SEGMENTED INFORMATION (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segmented Information
Revenues	$ 7,956	$ 13,263	$ 19,969	$ 26,119
Commodity and gas distribution costs	(3,108)	(8,441)	(11,126)	(16,213)
Operating and administrative	(1,801)	(1,695)	(3,401)	(3,320)
Income/(loss) from equity investments	327	413	490	826
Impairment of equity investments	0	0	(1,736)	0
Other income/(expense)	624	205	(523)	465
Earnings/(loss) before interest, income taxes, and depreciation and amortization	3,998	3,745	3,673	7,877
Depreciation and amortization	(949)	(842)	(1,831)	(1,682)
Interest expense	(681)	(637)	(1,387)	(1,322)
Income tax expense	(591)	(436)	(42)	(1,020)
Earnings	1,777	1,830	413	3,853
Capital expenditures	1,221	1,186	2,379	2,813
Intersegment Eliminations
Segmented Information
Revenues	(194)	(126)	(305)	(262)
Commodity and gas distribution costs	168	120	272	248
Operating and administrative	(246)	(47)	(147)	11
Income/(loss) from equity investments	0	0	0	1
Impairment of equity investments			0
Other income/(expense)	533	160	(525)	357
Earnings/(loss) before interest, income taxes, and depreciation and amortization	261	107	(705)	355
Capital expenditures	19	14	41	39
Liquids Pipelines | Business segments
Segmented Information
Revenues	2,945	2,569	4,479	5,227
Commodity and gas distribution costs	(1)	(7)	(8)	(13)
Operating and administrative	(782)	(776)	(1,647)	(1,577)
Income/(loss) from equity investments	148	204	345	401
Impairment of equity investments			0
Other income/(expense)	30	2	21	26
Earnings/(loss) before interest, income taxes, and depreciation and amortization	2,340	1,992	3,190	4,064
Capital expenditures	561	522	1,061	1,542
Gas Transmission and Midstream | Business segments
Segmented Information
Revenues	1,203	1,288	2,560	2,606
Commodity and gas distribution costs	0	0	0	0
Operating and administrative	(438)	(563)	(945)	(1,076)
Income/(loss) from equity investments	168	193	93	390
Impairment of equity investments			(1,736)
Other income/(expense)	17	23	(76)	41
Earnings/(loss) before interest, income taxes, and depreciation and amortization	950	941	(104)	1,961
Capital expenditures	429	424	820	818
Gas Distribution and Storage | Business segments
Segmented Information
Revenues	903	977	2,585	3,168
Commodity and gas distribution costs	(254)	(344)	(1,126)	(1,608)
Operating and administrative	(269)	(268)	(518)	(562)
Income/(loss) from equity investments	(8)	2	15	13
Impairment of equity investments			0
Other income/(expense)	11	23	31	41
Earnings/(loss) before interest, income taxes, and depreciation and amortization	383	390	987	1,052
Capital expenditures	204	223	426	396
Renewable Power Generation and Transmission | Business segments
Segmented Information
Revenues	150	137	303	289
Commodity and gas distribution costs	0	(1)	0	(2)
Operating and administrative	(37)	(40)	(87)	(82)
Income/(loss) from equity investments	21	4	37	18
Impairment of equity investments			0
Other income/(expense)	29	(6)	30	(5)
Earnings/(loss) before interest, income taxes, and depreciation and amortization	163	94	283	218
Capital expenditures	7	2	30	16
Energy Services | Business segments
Segmented Information
Revenues	2,949	8,418	10,347	15,091
Commodity and gas distribution costs	(3,021)	(8,209)	(10,264)	(14,838)
Operating and administrative	(29)	(1)	(57)	(34)
Income/(loss) from equity investments	(2)	10	0	3
Impairment of equity investments			0
Other income/(expense)	4	3	(4)	5
Earnings/(loss) before interest, income taxes, and depreciation and amortization	(99)	221	22	227
Capital expenditures	$ 1	$ 1	$ 1	$ 2