DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE COMMODITY VOLUMES (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2019 MWh MMBTU	Dec. 31, 2018 MWh MMBTU
Natural Gas Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	33	35
Electric Energy Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount	2	2
Congestion Revenue Rights Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount	50	52
SDG&E [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	32	33
SDG&E [Member] | Electric Energy Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount	2	2
SDG&E [Member] | Congestion Revenue Rights Derivative [Member]
Derivative [Line Items]
Derivative, nonmonetary notional amount	50	52