GENERAL INFORMATION AND OTHER FINANCIAL DATA - OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 242	$ 242		$ 242		$ 698
Accumulated amortization	(21)	(21)		(21)		(102)
Net intangible assets	221	221		221		596
Amortization expense		5	$ 4	10	$ 8
Future amortization expense per year				$ 12
Development rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				50 years
Gross intangible assets	0	0		$ 0		322
Accumulated amortization	0	0		$ 0		(60)
Renewable energy transmission and consumption permit [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				19 years
Gross intangible assets	154	154		$ 154		154
Accumulated amortization	(12)	(12)		$ (12)		(8)
Storage rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				46 years
Gross intangible assets	0	0		$ 0		138
Accumulated amortization	0	0		$ 0		(28)
O&M agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				23 years
Gross intangible assets	66	66		$ 66		66
Accumulated amortization	(2)	(2)		(2)		0
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	22	22		22		18
Accumulated amortization	(7)	$ (7)		$ (7)		$ (6)
Other [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				10 years
Sempra LNG & Midstream [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	369
Disposal Group Held-for-sale [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment charges	1,500
Disposal Group Held-for-sale [Member] | Sempra LNG & Midstream [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment charges	$ 1,300