NET INCOME PER LIMITED PARTNER UNIT (Basic and Diluted Net Income Per Limited Partner Unit) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss)		$ (60.5)	$ 112.5	$ 157.3	$ 268.2
Less Net income (loss) attributable to noncontrolling interest		(10.0)	(42.4)	(61.3)	(78.7)
Less Net income (loss) attributable to Series 1 preferred unit distributions		(22.5)	(22.5)	(45.0)	(45.0)
Less Net income (loss) attributable to Accretion of discount on Series 1 preferred units		(4.1)	(3.7)	(8.0)	(7.3)
Net income (loss) attributable to general and limited partner ownership interests in Enbridge Energy Partners, L.P.		(97.1)	43.9	43.0	137.2
Incentive distributions		(5.1)	(38.0)	(8.5)	(71.2)
Total distributed earnings to our General Partner, Class D and Class E units and IDUs		(59.4)	(42.5)	(115.8)	(79.3)
Total distributed earnings attributed to our common units and i-units		(198.5)	(182.2)	(392.0)	(359.9)
Total distributed earnings		(257.9)	(224.7)	(507.8)	(439.2)
Overdistributed earnings		$ (355.0)	$ (180.8)	$ (464.8)	$ (302.0)
Weighted average common units and i-units outstanding (in shares)		339,900,000	327,600,000	336,300,000	327,000,000
Basic and diluted earnings per unit:
Distributed earnings per common unit and i-unit (in dollars per share)	[1]	$ 0.58	$ 0.56	$ 1.17	$ 1.10
Overdistributed earnings per common unit and i-unit (in dollars per share)	[2]	(1.02)	(0.54)	(1.35)	(0.91)
Net income (loss) per common unit and i-unit (basic) (in dollars per share)	[3]	(0.44)	0.02	(0.18)	0.19
Net income (loss) per common unit and i-unit (diluted) (in dollars per share)	[3]	$ (0.44)	$ 0.02	$ (0.18)	$ 0.19
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Preferred Units excluded (in shares)		43,201,310	43,201,310	43,201,310	43,201,310
Class D Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Preferred Units excluded (in shares)		66,100,000		66,100,000
Class E Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive Preferred Units excluded (in shares)		18,114,975		18,114,975
General Partner [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings attributed to our General Partner		$ (5.2)	$ (4.5)	$ (10.2)	$ (8.1)
Class D and Class E Units [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total distributed earnings to our General Partner, Class D and Class E units and IDUs		$ (49.1)		$ (97.1)

[1] Represents the total distributed earnings to common units and i-units divided by the weighted average number of common units and i-units outstanding for the period.

[2] Represents the common units' and i-units' share (98%) of distributions in excess of earnings divided by the weighted average number of common units and i-units outstanding for the period and overdistributed earnings allocated to the common units and i-units based on the distribution waterfall that is outlined in our partnership agreement.

[3] For the three and six months ended June 30, 2015, 43,201,310 anti-dilutive Preferred units, 66,100,000 anti-dilutive Class D units and 18,114,975 anti-dilutive Class E units were excluded from the if-converted method of calculating diluted earnings per unit. For the three and six months ended June 30, 2014, 43,201,310 anti-dilutive Preferred units were excluded from the if-converted method of calculating diluted earnings per unit.