PARTNERS' CAPITAL (Schedule of Equity Interests) (Details)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Master limited partnership ownership interest (in percentage)		100.00%	100.00%
General Partner interest [Member]
Master limited partnership ownership interest (in percentage)		2.00%
Enbridge Energy Company, Inc [Member] | Enbridge Energy Management, LLC [Member]
Master limited partnership ownership interest (in percentage)		11.70%	11.70%
Limited Partner [Member]
Master limited partnership ownership interest (in percentage)		98.00%
Limited Partner [Member] | Public Common Unitholders [Member] | Class A Common Units [Member]
Master limited partnership ownership interest (in percentage)		43.70%	44.50%
Preferred Partner [Member]
Master limited partnership ownership interest (in percentage)		9.70%	9.90%
General Partner [Member]
Master limited partnership ownership interest (in percentage)		41.70%	42.20%
General Partner [Member] | General Partner interest [Member]
Master limited partnership ownership interest (in percentage)	[1]	2.00%	2.00%
General Partner [Member] | Class A Common Units [Member]
Master limited partnership ownership interest (in percentage)		9.40%	9.60%
General Partner [Member] | Class B Common Units [Member]
Master limited partnership ownership interest (in percentage)		1.60%	1.60%
General Partner [Member] | Class D Units [Member]
Master limited partnership ownership interest (in percentage)		13.30%	13.60%
General Partner [Member] | Class E Units [Member]
Master limited partnership ownership interest (in percentage)		3.70%	3.70%
I Units [Member] | Limited Partner [Member] | Enbridge Energy Company, Inc [Member]
Master limited partnership ownership interest (in percentage)	[2]	16.60%	15.10%
Incentive Distribution Units [Member] | General Partner [Member] | Public Common Unitholders [Member]
Master limited partnership ownership interest (in percentage)		0.00%	0.00%

[1] For the year ended December 31, 2014, we paid $2.9 million in total incentive distributions to the General Partner before the IDUs were issued.

[2] For the years ended December 31, 2016 and 2015, our General Partner owned 11.7% of Enbridge Management, which owns all of our i-units.