GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Inventory [Line Items]
Natural gas	$ 110	$ 95
LNG	6	4
Materials and supplies	154	159
Inventory	270	258	[1]
SDG&E [Member]
Inventory [Line Items]
Natural gas	1	0
LNG	0	0
Materials and supplies	91	102
Inventory	92	102
SoCalGas [Member]
Inventory [Line Items]
Natural gas	87	92
LNG	0	0
Materials and supplies	47	42
Inventory	134	134
Sempra Mexico [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	6	4
Materials and supplies	16	15
Inventory	22	19
Sempra LNG [Member]
Inventory [Line Items]
Natural gas	22	3
LNG	0	0
Materials and supplies	0	0
Inventory	$ 22	$ 3

[1] Derived from audited financial statements.