GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Inventory [Line Items]
Natural gas	$ 127	$ 110
LNG	2	9
Materials and supplies	180	158
Inventory	309	277	[1]
San Diego Gas and Electric Company [Member]
Inventory [Line Items]
Natural gas	0	1
LNG	0	0
Materials and supplies	105	93
Inventory	105	94	[1]
Southern California Gas Company [Member]
Inventory [Line Items]
Natural gas	104	90
LNG	0	0
Materials and supplies	56	46
Inventory	$ 160	$ 136	[1]

[1] Derived from audited financial statements.