QUARTERLY OPERATIONS Quarterly Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating revenues	$ 139	$ 126	$ 128	$ 155	$ 143	$ 132	$ 128	$ 178	$ 548	$ 581	$ 1,085
Operating income	43	26	31	53	38	31	34	90	153	193	(382)
Net income (loss)	24	76	(6)	31	(7)	23	16	(35)	125	(3)	(535)
Net income (loss) attributable to partners	$ 24	$ 76	$ (6)	$ 31	$ (7)	$ 23	$ 16	$ (41)	$ 125	$ (9)	$ (499)