GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Natural gas	$ 139	$ 118
LNG	13	7
Materials and supplies	187	183
Inventory	339	308	[1]
San Diego Gas and Electric Company [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	109	104
Inventory	109	104	[1]
Southern California Gas Company [Member]
Inventory [Line Items]
Natural gas	62	94
LNG	0	0
Materials and supplies	64	59
Inventory	$ 126	$ 153	[1]

[1] Derived from audited financial statements.