DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE COMMODITY VOLUMES (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2021 MMBTU MWh	Dec. 31, 2020 MWh MMBTU
Natural Gas Derivative [Member] | Short
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	7
Natural Gas Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU		5
Electric Energy Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MWh	1	1
Congestion Revenue Rights Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MWh	41	43
SDG&E [Member] | Natural Gas Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	10	16
SDG&E [Member] | Electric Energy Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MWh	1	1
SDG&E [Member] | Congestion Revenue Rights Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MWh	41	43
SoCalGas [Member] | Natural Gas Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	0	1