SHAREHOLDERS' EQUITY (Schedule of Share Distributions) (Details) - USD ($) $ / shares in Units, $ in Millions | Feb. 13, 2015 | Aug. 14, 2015 | May. 15, 2015 | Sep. 30, 2015 | Sep. 30, 2014 |
Distributions [Line Items] | | | | | |
Non-cash financing activities | | | | $ 119.5 | $ 106.7 |
First Quarter Distribution [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distribution Declaration Date | | | | Jan. 29, 2015 | |
Record Date | | | | Feb. 6, 2015 | |
Distribution Payment Date | | | | Feb. 13, 2015 | |
Distribution per Unit of the Partnership (in dollars per share) | $ 0.5700 | | | | |
Distributions (in shares) | 1,038,375 | | | | |
First Quarter Distribution [Member] | Public [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | 917,024 | | | | |
First Quarter Distribution [Member] | General Partner of Enbridge Energy Partners LP [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | 121,351 | | | | |
First Quarter Distribution [Member] | Weighted Average [Member] | | | | | |
Distributions [Line Items] | | | | | |
Closing Price of the Listed Shares (in dollars per share) | $ 37.50 | | | | |
Second Quarter Distribution [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distribution Declaration Date | | | | Apr. 30, 2015 | |
Record Date | | | | May 8, 2015 | |
Distribution Payment Date | | | | May 15, 2015 | |
Distribution per Unit of the Partnership (in dollars per share) | | | $ 0.5700 | | |
Distributions (in shares) | | | 1,061,026 | | |
Second Quarter Distribution [Member] | Public [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | | | 937,028 | | |
Second Quarter Distribution [Member] | General Partner of Enbridge Energy Partners LP [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | | | 123,998 | | |
Second Quarter Distribution [Member] | Weighted Average [Member] | | | | | |
Distributions [Line Items] | | | | | |
Closing Price of the Listed Shares (in dollars per share) | | | $ 37.25 | | |
Third Quarter Distribution [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distribution Declaration Date | | | | Jul. 30, 2015 | |
Record Date | | | | Aug. 7, 2015 | |
Distribution Payment Date | | | | Aug. 14, 2015 | |
Distribution per Unit of the Partnership (in dollars per share) | | $ 0.5830 | | | |
Distributions (in shares) | | 1,337,969 | | | |
Third Quarter Distribution [Member] | Public [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | | 1,181,605 | | | |
Third Quarter Distribution [Member] | General Partner of Enbridge Energy Partners LP [Member] | | | | | |
Distributions [Line Items] | | | | | |
Distributions (in shares) | | 156,364 | | | |
Third Quarter Distribution [Member] | Weighted Average [Member] | | | | | |
Distributions [Line Items] | | | | | |
Closing Price of the Listed Shares (in dollars per share) | | $ 30.68 | | | |