SEGMENTED INFORMATION (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segmented Information
Revenues	$ 13,263	$ 10,745	$ 26,119	$ 23,471
Commodity and gas distribution costs	(8,441)	(6,699)	(16,213)	(15,020)
Operating and administrative	(1,695)	(1,636)	(3,320)	(3,277)
Asset impairment	0	(10)	0	(1,072)
Income/(loss) from equity investments	413	363	826	698
Other	205	(14)	465	(134)
Earnings/(loss) before interest and income taxes	3,745	2,749	7,877	4,666
Depreciation and amortization	(842)	(829)	(1,682)	(1,653)
Interest expense	(637)	(690)	(1,322)	(1,346)
Income tax recovery/(expense)	(436)	97	(1,020)	170
Earnings	1,830	1,327	3,853	1,837
Capital expenditures	1,186	1,628	2,813	3,271
Intersegment Eliminations
Segmented Information
Revenues	(126)	(124)	(262)	(270)
Commodity and gas distribution costs	120	125	248	271
Operating and administrative	(47)	(60)	11	(157)
Asset impairment		0		(5)
Income/(loss) from equity investments	0	0	1	0
Other	160	(59)	357	(236)
Earnings/(loss) before interest and income taxes	107	(118)	355	(397)
Capital expenditures	14	2	39	8
Liquids Pipelines | Business segments
Segmented Information
Revenues	2,569	1,950	5,227	3,859
Commodity and gas distribution costs	(7)	(5)	(13)	(9)
Operating and administrative	(776)	(714)	(1,577)	(1,461)
Asset impairment		(10)		(154)
Income/(loss) from equity investments	204	137	401	268
Other	2	(36)	26	(25)
Earnings/(loss) before interest and income taxes	1,992	1,322	4,064	2,478
Capital expenditures	522	510	1,542	1,125
Gas Transmission and Midstream | Business segments
Segmented Information
Revenues	1,288	1,864	2,606	3,801
Commodity and gas distribution costs	0	(591)	0	(1,211)
Operating and administrative	(563)	(534)	(1,076)	(1,041)
Asset impairment		0		(913)
Income/(loss) from equity investments	193	229	390	437
Other	23	46	41	67
Earnings/(loss) before interest and income taxes	941	1,014	1,961	1,140
Capital expenditures	424	867	818	1,692
Gas Distribution | Business segments
Segmented Information
Revenues	977	1,070	3,168	3,307
Commodity and gas distribution costs	(344)	(444)	(1,608)	(1,832)
Operating and administrative	(268)	(271)	(562)	(519)
Asset impairment		0		0
Income/(loss) from equity investments	2	(10)	13	7
Other	23	25	41	43
Earnings/(loss) before interest and income taxes	390	370	1,052	1,006
Capital expenditures	223	239	396	422
Renewable Power Generation and Transmission | Business segments
Segmented Information
Revenues	137	149	289	306
Commodity and gas distribution costs	(1)	0	(2)	0
Operating and administrative	(40)	(36)	(82)	(66)
Asset impairment		0		0
Income/(loss) from equity investments	4	4	18	(21)
Other	(6)	9	(5)	16
Earnings/(loss) before interest and income taxes	94	126	218	235
Capital expenditures	2	10	16	24
Energy Services | Business segments
Segmented Information
Revenues	8,418	5,836	15,091	12,468
Commodity and gas distribution costs	(8,209)	(5,784)	(14,838)	(12,239)
Operating and administrative	(1)	(21)	(34)	(33)
Asset impairment		0		0
Income/(loss) from equity investments	10	3	3	7
Other	3	1	5	1
Earnings/(loss) before interest and income taxes	221	35	227	204
Capital expenditures	$ 1	$ 0	$ 2	$ 0