GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Inventory [Line Items]
Natural gas	$ 87	$ 109
LNG	10	11
Materials and supplies	191	187
Inventory	288	307	[1]
SDG&E [Member]
Inventory [Line Items]
Natural gas	0	4
LNG	0	0
Materials and supplies	105	101
Inventory	105	105
SoCalGas [Member]
Inventory [Line Items]
Natural gas	41	75
LNG	0	0
Materials and supplies	39	49
Inventory	80	124
Sempra South American Utilities [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	34	30
Inventory	34	30
Sempra Mexico [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	10	7
Materials and supplies	13	2
Inventory	23	9
Sempra Renewables [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	0	5
Inventory	0	5
Sempra LNG & Midstream [Member]
Inventory [Line Items]
Natural gas	46	30
LNG	0	4
Materials and supplies	0	0
Inventory	46	34
Southern California Gas Company [Member]
Inventory [Line Items]
Inventory	80	$ 124	[1]
Disposal Group Held-for-sale [Member] | Sempra Renewables [Member]
Inventory [Line Items]
Inventory	$ 5

[1] Derived from audited financial statements.