TAXES ON INCOME Income Taxes - Effective Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended								6 Months Ended		9 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	Jun. 30, 2015	Jun. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Effective Income Tax Rate Reconciliation [Line Items]
Computed statutory income tax expense at 35%													$ 55	$ 50	$ (165)
Premium on debt retirement													0	(10)	0
State income taxes, net of federal income tax benefit													9	36	21
Non-deductible goodwill impairment													0	0	241
Other													(5)	1	1
Effective Income Tax Rate Reconciliation, Audit Settlements													(7)	0	0
Total income tax expense	$ 17	$ 23	$ 0	$ 12	$ 47	$ 8	$ 23	$ 104	$ 12	$ 127	$ 35	$ 135	52	182	98
Trunkline LNG Transaction [Member]
Schedule of Effective Income Tax Rate Reconciliation [Line Items]
Other													$ 0	$ 105	$ 0