GENERAL INFORMATION AND OTHER FINANCIAL DATA - OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets		$ 252		$ 252		$ 698
Accumulated amortization		(23)		(23)		(102)
Net intangible assets		229		229		596
Amortization expense		3	$ 5	13	$ 13
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		322
Accumulated amortization		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
Accumulated amortization		(14)		$ (14)		(8)
Storage rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				46 years
Gross intangible assets		0		$ 0		138
Accumulated amortization		0		$ 0		(28)
O&M agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)				23 years
Gross intangible assets		66		$ 66		66
Accumulated amortization		(2)		(2)		0
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets		32		32		18
Accumulated amortization		$ (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