DEBT (MEP Credit Agreement) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2015 USD ($) requests		Jun. 30, 2014 USD ($)	Jul. 02, 2015 USD ($)
Line of Credit Facility [Line Items]
Total credit available	$ 2,625.0	[1]		$ 2,500.0
Outstanding amount	810.0
Net borrowings (repayments) under credit facility (Note 8)	(300.0)		$ 140.0
Midcoast Energy Partners [Member]
Line of Credit Facility [Line Items]
Net borrowings (repayments) under credit facility (Note 8)	50.0
Proceeds from lines of credit	2,505.0
Repayments of lines of credit	2,455.0
Senior Revolving Credit Facility [Member] | Midcoast Energy Partners [Member]
Line of Credit Facility [Line Items]
Total credit available	$ 850.0
Facility term	3 years
Credit facility maturity date	Sep. 30, 2017
Number of one-year requests for extensions | requests	4
Outstanding amount	$ 410.0
Debt, weighted average interest rate (in percentage)	2.40%
Senior Revolving Credit Facility [Member] | Midcoast Energy Partners [Member] | Portion of Credit Facility Maturing in 2016 [Member]
Line of Credit Facility [Line Items]
Total Credit available under Credit Facilities	$ 140.0
Credit facility maturity date	Nov. 13, 2016

[1] On July 2, 2015, we had an amendment to our 364-day Credit Facility. After the amendment on a pro-forma basis our total credit available under our Credit Facilities is $2,500.0 million, and the total amount available under the Credit Facilities and the EUS 364-day Credit Facility, less amounts outstanding, is $865.2 million.