GENERAL INFORMATION AND OTHER FINANCIAL DATA - CAPITALIZED FINANCING COSTS (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	$ 51	$ 82
San Diego Gas and Electric Company [Member]
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	24	20
Southern California Gas Company [Member]
Capitalized Financing Costs Disclosure [Line Items]
Total capitalized financing costs	$ 13	$ 15