SUBSEQUENT EVENTS (Details) $ in Millions, $ in Billions	Aug. 01, 2018 CAD ($)	May 09, 2018 CAD ($)	Aug. 01, 2018 USD ($)	Jul. 04, 2018 CAD ($)	May 09, 2018 USD ($)
The Assets
SUBSEQUENT EVENTS
Proceeds from sale of equity method investments		$ 1,750
The Assets | Subsequent Event
SUBSEQUENT EVENTS
Proceeds from sale of equity method investments	$ 1,750
Canadian Natural Gas Gathering and Processing Business | Disposal Group, Held-for-sale, Not Discontinued Operations | Subsequent Event
SUBSEQUENT EVENTS
Disposal group, consideration				$ 4,310
Midcoast Operating L.P. | Disposal Group, Held-for-sale, Not Discontinued Operations | Enbridge (U.S.) Inc.
SUBSEQUENT EVENTS
Disposal group, consideration					$ 1.1
Midcoast Operating L.P. | Disposed of by sale, not discontinued operations | Subsequent Event | Enbridge (U.S.) Inc.
SUBSEQUENT EVENTS
Disposal group, consideration			$ 1.1