INVESTMENTS IN UNCONSOLIDATED ENTITIES - Summarized Financial Information (Details) - USD ($) $ in Millions	3 Months Ended	4 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Schedule of Equity Method Investments [Line Items]
Net income / Earnings	$ 113	$ 128
Oncor Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Operating revenues	1,021	1,257
Operating expense	(730)	(915)
Income from operations	291	342
Interest expense	(87)	(109)
Income tax expense	(45)	(52)
Net income / Earnings	141	160
Noncontrolling interest held by TTI	$ (28)	$ (32)