REVENUES - CONTRACT LIABILITIES (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Contract with Customer, Liability [Roll Forward]
Contract liabilities, opening balance	$ (207)	$ (163)
Revenue from performance obligations satisfied during reporting period	36	3
Payments received in advance	(1)	0
Contract liabilities, closing balance	(172)	(160)
Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(8)
Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(164)
San Diego Gas and Electric Company [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, opening balance	(87)	(91)
Revenue from performance obligations satisfied during reporting period	3	3
Contract liabilities, closing balance	(84)	$ (88)
San Diego Gas and Electric Company [Member] | Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(4)
San Diego Gas and Electric Company [Member] | Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	$ (80)