REVENUES - CONTRACT LIABILITIES (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Contract with Customer, Liability [Roll Forward]
Contract liabilities, opening balance	$ (207)	$ (163)
Revenue from performance obligations satisfied during reporting period	49	2
Payments received in advance	(1)	0
Contract liabilities, closing balance	(159)	(161)
Other Current Liabilities [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(6)
Deferred Credits and Other [Member]
Contract with Customer, Liability [Roll Forward]
Contract liabilities, closing balance	(153)
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	2	2
Contract liabilities, closing balance	(85)	$ (89)
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	$ (81)