UNIT-BASED COMPENSATION PLANS - LTIP Activity for the Period (Details) - Long Term Incentive Plan 2013 $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares
Number of LP Units
Beginning Balance (in shares) | shares	1,296
Granted (in shares) | shares	547
Performance adjustment (in shares) | shares	32
Vested (in shares) | shares	(333)
Forfeited (in shares) | shares	(32)
Ending Balance (in shares) | shares	1,510
Weighted Average Grant Date Fair Value per LP Unit
Beginning Balance (in dollars per share) | $ / shares	$ 63.54
Granted (in dollars per share) | $ / shares	69.93
Performance adjustment (in dollars per share) | $ / shares	71.50
Vested (in dollars per share) | $ / shares	70.30
Forfeited (in dollars per share) | $ / shares	64.48
Ending Balance (in dollars per share) | $ / shares	$ 64.47
Additional disclosures
Compensation expense expected to be recognized | $	$ 40.5
Unrecognized compensation cost, weighted average period of recognition	1 year 9 months 22 days