CASH DISTRIBUTIONS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Common units
Distributions
Partnership distribution (in dollars per unit)	$ 0.89	$ 0.84	$ 2.57	$ 2.46
Limited Partner and General Partner interests combined | Common units
Distributions
Partnership distribution	$ 59.0	$ 54.0	$ 169.0	$ 157.0
General Partner
Distributions
Incentive distribution paid to the General Partner	$ 0.9	$ 0.3	$ 1.5	$ 0.3