DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE COMMODITY VOLUMES (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2021 MWh MMBTU	Dec. 31, 2020 MMBTU MWh
Natural Gas Derivative [Member] | Short
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	(14)
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	(48)	(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	(48)	(43)
SoCalGas [Member] | Natural Gas Derivative [Member] | Long
Derivative [Line Items]
Derivative, nonmonetary notional amount | MMBTU	0	(1)