GENERAL INFORMATION AND OTHER FINANCIAL DATA - INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense from continuing operations	$ 99	$ 61		$ 60	$ 150
Income from continuing operations before income taxes and equity earnings	201	448		1,061	1,235
Equity earnings (losses), before income tax	117	17		158	24
Pretax income	$ 318	$ 465		$ 1,219	$ 1,259
Effective income tax rate (as a percent)	31.00%	13.00%		5.00%	12.00%
Income tax expense (benefit) related to outside basis differences existing prior to the January 25, 2019 approval of our plan to sell our South American businesses		$ (192)	$ 103		$ (89)
Income tax expense (benefit) related to the increase in outside basis differences from 2019 earnings since January 25, 2019				$ (7)	32
San Diego Gas and Electric Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense from continuing operations	$ 33	71		161	111
Income from continuing operations before income taxes and equity earnings	$ 211	$ 337		$ 794	$ 700
Effective income tax rate (as a percent)	16.00%	21.00%		20.00%	16.00%
Income tax benefit for release of a regulatory liability				$ 31
Southern California Gas Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense from continuing operations	$ (6)	$ 35		95	$ 50
Income from continuing operations before income taxes and equity earnings	$ (30)	$ 178		$ 521	$ 488
Effective income tax rate (as a percent)	20.00%	20.00%		18.00%	10.00%
Income tax benefit for release of a regulatory liability				$ 38