GENERAL INFORMATION AND OTHER FINANCIAL DATA - INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense from continuing operations	$ (342)	$ 99	$ (45)	$ 60
(Loss) income from continuing operations before income taxes and equity earnings	(1,365)	201	(316)	1,061
Equity earnings (losses), before income tax:	137	117	457	158
Pretax (loss) income	$ (1,228)	$ 318	$ 141	$ 1,219
Effective income tax rate (as a percent)	28.00%	31.00%	(32.00%)	5.00%
Income tax benefit related to the increase in outside basis differences				$ 7
San Diego Gas and Electric Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense from continuing operations	$ 90	$ 33	$ 168	161
(Loss) income from continuing operations before income taxes and equity earnings	$ 295	$ 211	$ 771	$ 794
Effective income tax rate (as a percent)	31.00%	16.00%	22.00%	20.00%
Southern California Gas Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax (benefit) expense from continuing operations	$ (437)	$ (6)	$ (335)	$ 95
(Loss) income from continuing operations before income taxes and equity earnings	$ (1,563)	$ (30)	$ (959)	$ 521
Effective income tax rate (as a percent)	28.00%	20.00%	35.00%	18.00%