SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - OTHER NONCONTROLLING INTERESTS (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Other noncontrolling interests	$ 2,450	$ 2,270
SDG&E [Member] | Otay Mesa VIE [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	100.00%	100.00%
Other noncontrolling interests	$ 28	$ 37
Sempra South American Utilities [Member] | Chilquinta Energia subsidiaries [Member]
Noncontrolling Interest [Line Items]
Other noncontrolling interests	$ 24	$ 22
Sempra South American Utilities [Member] | Chilquinta Energia subsidiaries [Member] | Minimum [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	22.90%	23.10%
Sempra South American Utilities [Member] | Chilquinta Energia subsidiaries [Member] | Maximum [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	43.40%	43.40%
Sempra South American Utilities [Member] | Luz Del Sur [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	16.40%	16.40%
Other noncontrolling interests	$ 189	$ 173
Sempra South American Utilities [Member] | Tecsur [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	9.80%	9.80%
Other noncontrolling interests	$ 4	$ 4
Sempra Mexico [Member] | IEnova [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	33.60%	33.60%	33.60%	18.90%
Other noncontrolling interests	$ 1,532	$ 1,524
Sempra Renewables [Member] | Tax equity arrangement – wind [Member]
Noncontrolling Interest [Line Items]
Other noncontrolling interests	181	92
Sempra Renewables [Member] | Tax equity arrangement – solar [Member]
Noncontrolling Interest [Line Items]
Other noncontrolling interests	$ 450	$ 376
Sempra LNG & Midstream [Member] | Bay Gas Storage Company [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	9.10%	9.10%
Other noncontrolling interests	$ 28	$ 27
Sempra LNG & Midstream [Member] | Liberty Gas Storage [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	23.30%	23.30%
Other noncontrolling interests	$ 14	$ 14
Sempra LNG & Midstream [Member] | Southern Gas Transmission [Member]
Noncontrolling Interest [Line Items]
Ownership percentage held by noncontrolling owners	0.00%	49.00%
Other noncontrolling interests	$ 0	$ 1