REVENUES - CONTRACT LIABILITIES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Contract with Customer, Liability [Roll Forward]
Contract liabilities, opening balance	$ (207)	$ (163)
Revenue from performance obligations satisfied during reporting period	25	1
Contract liabilities, closing balance	(182)	(162)
Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(28)
Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(154)
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	1	1
Contract liabilities, closing balance	(86)	$ (90)
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	$ (82)