ACQUISITIONS AND DISPOSITIONS - Dispositions (Narrative) (Details) € in Millions, $ in Millions, $ in Millions														12 Months Ended
	Dec. 31, 2019 CAD ($)	Nov. 01, 2019 USD ($)	Nov. 01, 2019 CAD ($)	Oct. 01, 2019 USD ($)	Oct. 01, 2019 CAD ($)	Oct. 01, 2018 CAD ($)	Aug. 01, 2018 USD ($)	Aug. 01, 2018 CAD ($)	Jul. 04, 2018 CAD ($)	Jul. 31, 2017 USD ($)	Jul. 31, 2017 CAD ($)	Mar. 01, 2017 USD ($)	Mar. 01, 2017 CAD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 CAD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2018 CAD ($)	Aug. 01, 2018 CAD ($)	Jul. 31, 2018	Jun. 30, 2018 CAD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill																					$ 33,153	$ 34,459
Deferred income tax (recovery)/expense														$ 1,156		$ (148)			$ (2,877)
Impairment loss														423		1,104			4,463
Impairment of goodwill														0		1,019			102
Gain on disposal of assets														(254)		(8)			120
Liquids Pipelines
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill																					7,951	8,324
Impairment of goodwill																0
Dispositions | St. Lawrence Gas
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of interest		$ 55	$ 72
Gain (loss) on disposal of interest			$ (10)
Dispositions | Enbridge Gas New Brunswick
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of interest				$ 331
Gain (loss) on disposal of interest					$ (3)
Goodwill included in assets subsequently disposed					$ 133
Dispositions | Canadian Natural Gas Gathering and Processing Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, consideration									$ 4,300
Impairment of goodwill									$ 1,019
Dispositions | Canadian Renewable Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of interest																62
Dispositions | United States Renewable Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of interest															$ 13	17
Dispositions | Liquids Pipelines | Sandpiper
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of assets															30	38		$ 111	148
Gain on disposal of assets															22	29		$ 63	$ 83
Dispositions | Liquids Pipelines | Olympic Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of interest										$ 160	$ 203
Dispositions | Liquids Pipelines | Ozark Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of assets												$ 220	$ 294
Gain on disposal of assets												$ 10	$ 14
Disposal group, held-for-sale, not discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other long-term liabilities (long-term liabilities held for sale)																					0	96
Disposal group, held-for-sale, not discontinued operations | Texas Express Ngl System
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill																									$ 262
Equity investment																									$ 447
Other income/(expense) | Dispositions | Hohe See Offshore Wind Project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of interest																(20)	€ (14)
Other income/(expense) | Dispositions | Liquids Pipelines | Olympic Pipeline
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of interest										$ 21	$ 27
Canadian Renewable Assets | Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, ownership percentage by parent																		49.00%	49.00%					49.00%
United States Renewable Assets | Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, ownership percentage by parent																								49.00%
Federally Regulated Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill included in assets subsequently disposed																					$ 55
Cash proceeds from sale of assets	$ 1,700
Gain on disposal of assets														$ (268)
Provincially Regulated Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from sale of assets						$ 2,500
Gain on disposal of assets																34
Hohe See Offshore Wind Project | Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest of equity method investment (as a percent)							49.00%																49.00%	49.00%
The Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of equity method investments								$ 1,750
Deferred income tax (recovery)/expense																(196)
The Assets | Renewable energy assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noncontrolling interest, ownership percentage by parent																				51.00%	51.00%
Renewable energy assets | The Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred income tax (recovery)/expense																(267)
Enbridge (U.S.) Inc. | Dispositions | Midcoast Operating L.P.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of interest							$ (32)	$ (41)
Disposal group, consideration							1,100																$ 1,400
Impairment loss																$ 913			$ 4,400
Other long-term liabilities (long-term liabilities held for sale)							$ 298								$ 274					$ 230	$ 299	$ 375	$ 387
Impairment of goodwill																			$ 102