DEBT - LONG TERM DEBT REPAYMENTS (Details)	1 Months Ended	6 Months Ended
	Mar. 31, 2018 USD ($)	Jun. 30, 2018 CAD ($)	Jun. 30, 2018 USD ($)	May 31, 2018 CAD ($)	Apr. 30, 2018 CAD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2018 CAD ($)
Enbridge Energy Partners, L.P. | 6.50% Senior Notes
DEBT
Face amount of notes issued						$ 400,000,000
Interest rate (as a percent)					6.50%	6.50%
Enbridge Pipelines Southern Lights L L C | 3.98% medium-term note due June 2040
DEBT
Face amount of notes issued			$ 20,000,000
Interest rate (as a percent)			3.98%
Enbridge Southern Lights L P | 4.014% medium-term note due June 2040
DEBT
Face amount of notes issued							$ 9,000,000
Interest rate (as a percent)							4.01%
Spectra Energy Capitals, LLC
DEBT
Gain (loss) on extinguishment of debt		$ 37,000,000	$ 29,000,000
Spectra Energy Capitals, LLC | 6.75% Senior Unsecured Notes Due 2032
DEBT
Face amount of notes issued	$ 64,000,000
Interest rate (as a percent)	6.75%
Repayments of debt	$ 80,000,000
Spectra Energy Capitals, LLC | 7.50% Senior Unsecured Notes Due 2038
DEBT
Face amount of notes issued	$ 43,000,000
Interest rate (as a percent)	7.50%
Repayments of debt	$ 59,000,000
Spectra Energy Capitals, LLC | 5.65% Senior Unsecured Notes Due 2020
DEBT
Face amount of notes issued	$ 163,000,000
Interest rate (as a percent)	5.65%
Repayments of debt	$ 172,000,000
Spectra Energy Capitals, LLC | 3.30% Senior Unsecured Notes Due 2023
DEBT
Face amount of notes issued	$ 498,000,000
Interest rate (as a percent)	3.30%
Repayments of debt	$ 508,000,000
Spectra Energy Capitals, LLC | 6.20% Senior Notes
DEBT
Face amount of notes issued						$ 272,000,000
Interest rate (as a percent)					6.20%	6.20%
Spectra Energy Capitals, LLC | 5.35% Medium-Term Notes
DEBT
Interest rate (as a percent)					5.35%	5.35%
Union Gas Limited | 5.35% Medium-Term Notes
DEBT
Face amount of notes issued					$ 200,000,000
Westcoast Energy Inc | 6.9% senior secured notes
DEBT
Face amount of notes issued				$ 13,000,000
Interest rate (as a percent)				6.90%
Westcoast Energy Inc | 4.34% senior secured notes
DEBT
Face amount of notes issued				$ 4,000,000
Interest rate (as a percent)				4.34%