GENERAL INFORMATION AND OTHER FINANCIAL DATA - INVENTORIES (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Natural gas	$ 93	$ 109
LNG	7	11
Materials and supplies	185	187
Total	285	307	[1]
SDG&E [Member]
Inventory [Line Items]
Natural gas	2	4
LNG	0	0
Materials and supplies	104	101
Total	106	105
SoCalGas [Member]
Inventory [Line Items]
Natural gas	55	75
LNG	0	0
Materials and supplies	41	49
Total	96	124
Sempra South American Utilities [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	32	30
Total	32	30
Sempra Mexico [Member]
Inventory [Line Items]
Natural gas	1	0
LNG	7	7
Materials and supplies	3	2
Total	11	9
Sempra Renewables [Member]
Inventory [Line Items]
Natural gas	0	0
LNG	0	0
Materials and supplies	5	5
Total	5	5
Sempra LNG & Midstream [Member]
Inventory [Line Items]
Natural gas	35	30
LNG	0	4
Materials and supplies	0	0
Total	35	34
Southern California Gas Company [Member]
Inventory [Line Items]
Total	$ 96	$ 124	[1]

[1] Derived from audited financial statements.