GENERAL INFORMATION AND OTHER FINANCIAL DATA - OTHER NONCONTROLLING INTERESTS (Details) $ in Millions	3 Months Ended
	Dec. 31, 2017 USD ($) facility		Mar. 31, 2018 USD ($) subsidiary
Noncontrolling Interest [Line Items]
Noncontrolling interests	$ 2,450	[1]	$ 2,441
San Diego Gas and Electric Company [Member] | Otay Mesa VIE [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	100.00%		100.00%
Noncontrolling interests	$ 28		$ 30
Sempra South American Utilities [Member] | Chilquinta Energía subsidiaries [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests	$ 24		$ 26
Number of subsidiaries with noncontrolling interests | subsidiary			4
Sempra South American Utilities [Member] | Chilquinta Energía subsidiaries [Member] | Minimum [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	22.90%		22.90%
Sempra South American Utilities [Member] | Chilquinta Energía subsidiaries [Member] | Maximum [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	43.40%		43.40%
Sempra South American Utilities [Member] | Luz del Sur [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	16.40%		16.40%
Noncontrolling interests	$ 189		$ 193
Sempra South American Utilities [Member] | Tecsur [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	9.80%		9.80%
Noncontrolling interests	$ 4		$ 4
Sempra Mexico [Member] | IEnova [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	33.60%		33.60%
Noncontrolling interests	$ 1,532		$ 1,539
Sempra Renewables [Member] | Tax equity arrangement – wind [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests	181		167
Sempra Renewables [Member] | Tax equity arrangement – solar [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests	$ 450		$ 440
Sempra LNG & Midstream [Member] | Bay Gas Storage Company, Ltd. [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	9.10%		9.10%
Noncontrolling interests	$ 28		$ 29
Sempra LNG & Midstream [Member] | Liberty Gas Storage, LLC [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	23.30%		23.40%
Noncontrolling interests	$ 14		$ 13
Solar Power Projects [Member] | Tax Equity Investors [Member] | Sempra Renewables [Member]
Noncontrolling Interest [Line Items]
Number of facilities acquired | facility	4
Subsidiaries [Member] | Sempra Mexico [Member] | IEnova [Member]
Noncontrolling Interest [Line Items]
Percent ownership held by noncontrolling interests	10.00%

[1] Derived from audited financial statements.