GENERAL INFORMATION AND OTHER FINANCIAL DATA - CAPITALIZED FINANCING COSTS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	$ 49	$ 54	$ 157	$ 198
San Diego Gas and Electric Company [Member]
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	20	21	67	62
Southern California Gas Company [Member]
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	$ 10	$ 15	$ 39	$ 45