GENERAL INFORMATION AND OTHER FINANCIAL DATA - OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 440		$ 440		$ 250
Accumulated amortization	(64)		(64)		(48)
Net intangible assets	376		376		202
Amortization expense	6	$ 3	16	$ 8
Amortization expense recorded against revenue	4		7
Future amortization expense per year			7
Expected amortization charged against revenue			3
Future amortization expense, per year, next four years			26
Expected amortization expense, recorded in revenue, next four years			13
Renewable energy transmission and consumption permit [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	169		169		169
Accumulated amortization	(38)		$ (38)		(32)
Renewable energy transmission and consumption permit [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)			15 years
Renewable energy transmission and consumption permit [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)			19 years
O&M agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)			23 years
Gross intangible assets	66		$ 66		66
Accumulated amortization	(11)		$ (11)		(9)
PPA [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)			14 years
Gross intangible assets	190		$ 190		0
Accumulated amortization	(7)		(7)		0
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	15		15		15
Accumulated amortization	(8)		$ (8)		$ (7)
Other [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)			10 years
Sempra Mexico [Member] | PPA [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 190		$ 190