SEGMENT INFORMATION (Details) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015 USD ($)		Jun. 30, 2014 USD ($)		Jun. 30, 2015 USD ($) segments		Jun. 30, 2014 USD ($)		Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reporting segments (in segments) | segments						2
Commodity sales		$ 731.1		$ 1,342.4		$ 1,553.8	[1]	$ 2,941.9
Transportation and other services		582.0		528.7		1,187.9	[1]	1,008.8
Total operating revenues		1,313.1		1,871.1		2,741.7	[1]	3,950.7
Commodity costs		670.6		1,259.8		$ 1,449.7		2,748.5
Environmental costs, net of recoveries				38.2				43.2
Environmental costs, net of recoveries		(0.8)
Operating and administrative		207.2		224.6		$ 424.3		441.6
Power		57.2		$ 54.2		120.8		$ 104.6
Goodwill impairment		246.7				246.7
Asset impairment		12.3				12.3
Depreciation and amortization		129.5		$ 113.4		257.9		$ 217.2
Costs and Expenses, Total		1,322.7		1,690.2		2,511.7		3,555.1
Operating income (loss)		(9.6)		180.9		230.0		395.6
Interest expense, net		78.0		80.2		126.3		157.1
Allowance for equity used during construction		17.3		12.6		40.3		33.3
Other income (expense)		6.0		1.2		11.9		0.4
Income (loss) before income tax expense (benefit)		(64.3)		114.5		155.9		272.2
Income tax expense (benefit)		(3.8)		2.0		(1.4)		4.0
Net income (loss)		(60.5)		112.5		157.3		268.2
Less: Net income attributable to noncontrolling interest		10.0		42.4		61.3		78.7
Series 1 preferred unit distributions		22.5		22.5		45.0		45.0
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
Total assets		$ 18,013.2		$ 16,063.4		18,013.2		16,063.4		$ 17,746.9
Capital expenditures (excluding acquisitions)						$ 1,027.5		$ 1,091.5
Liquids [Member]
Segment Reporting Information [Line Items]
Commodity sales
Transportation and other services		$ 533.0		$ 474.3		$ 1,088.1	[1]	$ 907.0
Total operating revenues		$ 533.0		$ 474.3		$ 1,088.1	[1]	$ 907.0
Commodity costs
Environmental costs, net of recoveries				$ 38.2				$ 43.2
Environmental costs, net of recoveries		$ (0.8)
Operating and administrative		116.3		117.6		$ 246.7		226.0
Power		$ 57.2		54.2		$ 120.8		104.6
Goodwill impairment
Asset impairment
Depreciation and amortization		$ 88.7		76.6		$ 178.8		143.4
Costs and Expenses, Total		261.4		286.6		546.3		517.2
Operating income (loss)		$ 271.6		$ 187.7		$ 541.8		$ 389.8
Interest expense, net
Allowance for equity used during construction
Other income (expense)
Income (loss) before income tax expense (benefit)		$ 271.6		$ 187.7		$ 541.8		$ 389.8
Income tax expense (benefit)
Net income (loss)		$ 271.6		$ 187.7		$ 541.8		$ 389.8
Less: Net income attributable to noncontrolling interest
Series 1 preferred unit distributions
Accretion of discount on Series 1 preferred units
Net income (loss) attributable to general and limited partner ownership interests in Enbridge Energy Partners, L.P.		$ 271.6		$ 187.7		$ 541.8		$ 389.8
Total assets		12,564.1		10,335.9		12,564.1		10,335.9
Capital expenditures (excluding acquisitions)						909.0		985.0
Natural Gas [Member]
Segment Reporting Information [Line Items]
Commodity sales		731.1		1,342.4		1,553.8	[1]	2,941.9
Transportation and other services		49.0		54.4		99.8	[1]	101.8
Total operating revenues		780.1	[2]	1,396.8		1,653.6	[1]	3,043.7
Commodity costs		$ 670.6		$ 1,259.8		$ 1,449.7		$ 2,748.5
Environmental costs, net of recoveries
Environmental costs, net of recoveries
Operating and administrative		$ 87.3		$ 103.6		$ 170.0		$ 212.5
Power
Goodwill impairment		$ 246.7				$ 246.7
Asset impairment		12.3				12.3
Depreciation and amortization		40.8		$ 36.8		79.1		$ 73.8
Costs and Expenses, Total		1,057.7		1,400.2		1,957.8		3,034.8
Operating income (loss)		$ (277.6)		$ (3.4)		$ (304.2)		$ 8.9
Interest expense, net
Allowance for equity used during construction
Other income (expense)		$ 5.9	[3]	$ 2.3	[4]	$ 11.6	[5]	$ 1.0	[6]
Income (loss) before income tax expense (benefit)		$ (271.7)		$ (1.1)		$ (292.6)		$ 9.9
Income tax expense (benefit)
Net income (loss)		$ (271.7)		$ (1.1)		$ (292.6)		$ 9.9
Less: Net income attributable to noncontrolling interest
Series 1 preferred unit distributions
Accretion of discount on Series 1 preferred units
Net income (loss) attributable to general and limited partner ownership interests in Enbridge Energy Partners, L.P.		$ (271.7)		$ (1.1)		$ (292.6)		$ 9.9
Total assets		5,256.5	[7]	5,301.3	[8]	5,256.5	[7]	5,301.3	[8]
Capital expenditures (excluding acquisitions)						104.6		105.0
Equity Method Investments		$ 376.2		$ 381.6		$ 376.2		$ 381.6
Corporate [Member]
Segment Reporting Information [Line Items]
Commodity sales
Transportation and other services
Total operating revenues
Commodity costs
Environmental costs, net of recoveries
Environmental costs, net of recoveries	[9]
Operating and administrative		$ 3.6	[9]	$ 3.4	[10]	$ 7.6	[11]	$ 3.1	[12]
Power
Goodwill impairment
Asset impairment
Depreciation and amortization
Costs and Expenses, Total		$ 3.6	[9]	$ 3.4	[10]	$ 7.6	[11]	$ 3.1	[12]
Operating income (loss)		(3.6)	[9]	(3.4)	[10]	(7.6)	[11]	(3.1)	[12]
Interest expense, net		78.0	[9]	80.2	[10]	126.3	[11]	157.1	[12]
Allowance for equity used during construction		17.3	[9]	12.6	[10]	40.3	[11]	33.3	[12]
Other income (expense)		0.1	[9]	(1.1)	[10]	0.3	[11]	(0.6)	[12]
Income (loss) before income tax expense (benefit)		(64.2)	[9]	(72.1)	[10]	(93.3)	[11]	(127.5)	[12]
Income tax expense (benefit)		(3.8)	[9]	2.0	[10]	(1.4)	[11]	4.0	[12]
Net income (loss)		(60.4)	[9]	(74.1)	[10]	(91.9)	[11]	(131.5)	[12]
Less: Net income attributable to noncontrolling interest		10.0	[9]	42.4	[10]	61.3	[11]	78.7	[12]
Series 1 preferred unit distributions		22.5	[9]	22.5	[10]	45.0	[11]	45.0	[12]
Accretion of discount on Series 1 preferred units		4.1	[9]	3.7	[10]	8.0	[11]	7.3	[12]
Net income (loss) attributable to general and limited partner ownership interests in Enbridge Energy Partners, L.P.		(97.0)	[9]	(142.7)	[10]	(206.2)	[11]	(262.5)	[12]
Total assets		$ 192.6	[11]	$ 426.2	[12]	192.6	[11]	426.2	[12]
Capital expenditures (excluding acquisitions)						$ 13.9	[11]	$ 1.5	[12]

[1] There were no intersegment revenues for the six months ended June 30, 2015.

[2] There were no intersegment revenues for the three months ended June 30, 2015.

[3] Other income (expense) for our Natural Gas segment includes our equity investment in the Texas Express NGL system.

[4] Other income (expense) for our Natural Gas segment includes our equity investment in the Texas Express NGL system.

[5] Other income (expense) for our Natural Gas segment includes our equity investment in the Texas Express NGL system.

[6] Other income (expense) for our Natural Gas segment includes our equity investment in the Texas Express NGL system.

[7] Total assets for our Natural Gas segment include $376.2 million for our equity investment in the Texas Express NGL system.

[8] Total assets for our Natural Gas segment include $381.6 million for our equity investment in the Texas Express NGL system.

[9] Corporate consists of interest expense, interest income, allowance for equity used during construction, noncontrolling interest and other costs such as income taxes, which are not allocated to the business segments.

[10] Corporate consists of interest expense, interest income, allowance for equity used during construction, noncontrolling interest and other costs such as income taxes, which are not allocated to the business segments.

[11] Corporate consists of interest expense, interest income, allowance for equity used during construction, noncontrolling interest and other costs such as income taxes, which are not allocated to the business segments.

[12] Corporate consists of interest expense, interest income, allowance for equity used during construction, noncontrolling interest and other costs such as income taxes, which are not allocated to the business segments.