NET INCOME PER COMMON UNIT (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Net income per common unit
Net income attributable to controlling interests	$ 57us-gaap_NetIncomeLoss	$ 57us-gaap_NetIncomeLoss
Net income allocated to General Partner, including incentive distribution rights (IDRs)	1	1
Net income allocable to common units	$ 56	$ 56
Weighted average common units outstanding (millions) - basic (in units)	63.6	62.3
Weighted average common units outstanding (millions) - diluted (in units)	63.6	62.3
Net income per common unit - basic (in dollars per unit)	$ 0.88	$ 0.90
Net income per common unit - diluted (in dollars per unit)	$ 0.88	$ 0.90

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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