GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Inventory [Line Items]
Natural gas	$ 141	$ 109
LNG	6	11
Materials and supplies	198	187
Inventory	345	307	[1]
SDG&E [Member]
Inventory [Line Items]
Natural gas	1	4
LNG	0	0
Materials and supplies	102	101
Inventory	103	105
SoCalGas [Member]
Inventory [Line Items]
Natural gas	116	75
LNG	0	0
Materials and supplies	40	49
Inventory	156	124
Sempra South American Utilities [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	41	30
Inventory	41	30
Sempra Mexico [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	6	7
Materials and supplies	15	2
Inventory	21	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	24	30
LNG	0	4
Materials and supplies	0	0
Inventory	24	34
Southern California Gas Company [Member]
Inventory [Line Items]
Inventory	156	$ 124	[1]
Disposal Group Held-for-sale [Member] | Sempra Renewables [Member]
Inventory [Line Items]
Inventory	$ 5

[1] Derived from audited financial statements.