GENERAL INFORMATION AND OTHER FINANCIAL DATA - INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit) from continuing operations	$ 158	$ (207)
Income from continuing operations before income taxes and equity earnings	768	397
Equity earnings (losses), before income tax:	135	(43)
Pretax income	$ 903	$ 354
Effective income tax rate (as a percent)	18.00%	(58.00%)
Income tax benefit related to the increase in outside basis differences from 2019 earnings since January 25, 2019		$ 7
San Diego Gas and Electric Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit) from continuing operations	$ 45	58
Income from continuing operations before income taxes and equity earnings	$ 257	$ 320
Effective income tax rate (as a percent)	18.00%	18.00%
Southern California Gas Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit) from continuing operations	$ 94	$ 52
Income from continuing operations before income taxes and equity earnings	$ 501	$ 355
Effective income tax rate (as a percent)	19.00%	15.00%