SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - RESTRICTED NET ASSETS (Details) $ in Millions	Dec. 31, 2017 USD ($)
Significant Restrictions of Subsidiaries [Line Items]
Undistributed earnings of equity investments	$ 89
Sempra South American Utilities [Member] | Luz Del Sur [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	35
Sempra Mexico [Member] | Mexican Subsidiaries [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	198
Sempra Mexico [Member] | IEnova Pipelines [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	19
Sempra Mexico [Member] | Ventika [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	34
Sempra Mexico [Member] | Energia Sierra Juarez Wind Project [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 9
Ownership percentage in equity method investee	50.00%
Sempra Mexico [Member] | TAG Pipeline Norte [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 82
Ownership percentage in equity method investee	50.00%
Sempra Renewables [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 265
Sempra Renewables [Member] | Copper Mountain Solar 1 [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	8
Sempra Renewables [Member] | Tax Equity LLCs [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 19
Sempra Renewables [Member] | Joint Venture One [Member]
Significant Restrictions of Subsidiaries [Line Items]
Ownership percentage in equity method investee	50.00%
Sempra Renewables [Member] | Joint Venture Two [Member]
Significant Restrictions of Subsidiaries [Line Items]
Ownership percentage in equity method investee	25.00%
Sempra LNG & Midstream [Member] | Cameron LNG Holdings [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 7,000
Consolidated Entities [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	8,600
Unconsolidated Entities [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	7,400
San Diego Gas and Electric Company [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	5,100
Amount available for dividend distribution and loans without prior approval from regulatory agency	$ 469
Authorized percentage of equity	52.00%
Minimum common equity ratio	30.00%
Southern California Gas Company [Member]
Significant Restrictions of Subsidiaries [Line Items]
Restricted net assets of consolidated subsidiaries	$ 3,200
Amount available for dividend distribution and loans without prior approval from regulatory agency	$ 736
Authorized percentage of equity	52.00%
California Utilities [Member]
Significant Restrictions of Subsidiaries [Line Items]
Maximum ratio of indebtedness to total capitalization	0.65