DERIVATIVE FINANCIAL INSTRUMENTS - CASH FLOW HEDGES (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months	$ 22
Maximum length of time hedged in cash flow hedge	13 years
Equity Method Investee [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum length of time hedged in cash flow hedge	15 years
San Diego Gas and Electric Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum length of time hedged in cash flow hedge	1 year
San Diego Gas and Electric Company [Member] | Non-controlling interests [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months	$ (2)
Southern California Gas Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months	$ (1)