COMMITMENTS AND CONTINGENCIES - LEGAL PROCEEDINGS (Details) proof_of_claim in Thousands, £ in Millions		1 Months Ended				3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 21, 2020 plaintiff lawsuit	Oct. 31, 2018 plaintiff	Aug. 31, 2018 USD ($)	Jan. 31, 2017 lawsuit	Sep. 30, 2016 USD ($)	Jun. 30, 2019 lawsuit	Sep. 30, 2019 proof_of_claim	Dec. 31, 2019 USD ($) lawsuit	Dec. 31, 2019 GBP (£)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Aug. 31, 2017 lawsuit	Oct. 01, 2014 USD ($)	Oct. 01, 2014 GBP (£)
Loss Contingencies [Line Items]
Write-off of wildfire regulatory asset								$ 0		$ 0	$ 351,000,000
Reserve for Aliso Canyon costs								9,000,000		160,000,000
Sempra Energy [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								68,000,000
San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Write-off of wildfire regulatory asset								0		0	$ 351,000,000
Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								21,000,000
Recoverable costs through insurance settlement								1,086,000,000
Reserve for Aliso Canyon costs								9,000,000		160,000,000
Energy Future Holdings Corp. [Member]
Loss Contingencies [Line Items]
Proof of claims | proof_of_claim							28
Loss from Catastrophes, 2007 Wildfire [Member] | San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Write-off of wildfire regulatory asset										351,000,000
Write-off of wildfire regulatory asset net of tax										$ 208,000,000
Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								10,000,000
Net book value Of Aliso Canyon Natural Gas Storage Facility								769,000,000
Recorded estimated costs								$ 1,116,000,000
Percentage of recorded estimated costs allocated to temporary relocation program								51.00%
Reserve for Aliso Canyon costs								$ 9,000,000
Insurance receivable for Aliso Canyon costs								339,000,000
Proceeds from insurance settlement								$ 747,000,000
Shareholder Derivative Complaint [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Number of pending claims | lawsuit								5					4
Damages from Product Defects [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Maximum occupational safety And health fines					$ 75,000
Penalty assessments					233,500
Maximum other assessments in settlement of criminal complaint					$ 6,000,000
HMRC VAT Claim [Member] | R B S Sempra Commodities [Member]
Loss Contingencies [Line Items]
VAT tax claim paid upon appeal														$ 138,000,000
HMRC VAT Claim [Member] | Plaintiffs [Member]
Loss Contingencies [Line Items]
Damages sought								$ 95,000,000	£ 71.5
HMRC VAT Claim [Member] | Parent Company [Member]
Loss Contingencies [Line Items]
VAT tax claim paid upon appeal | £															£ 86.0
Minimum [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Liability insurance coverage								1,200,000,000
Maximum [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Liability insurance coverage								$ 1,400,000,000
Consolidated Class Action Complaints [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit				2
Property Class Action [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit				1
Complaints Filed by Firefighters [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff		51
Complaints Filed by Public Entities [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit						3
R B S Sempra Commodities [Member]
Loss Contingencies [Line Items]
Investment in RBS Sempra Commodities LLP												$ 65,000,000
Funding for Environmental Projects [Member] | Complaints Filed by Public Entities [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Settlement amount payable			$ 120,000,000
Civil Penalties [Member] | Complaints Filed by Public Entities [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Settlement amount payable			$ 21,000,000
Subsequent Event [Member] | Energy Future Holdings Corp. [Member]
Loss Contingencies [Line Items]
Number of pending claims | lawsuit	275
Number of lawsuits | lawsuit	182
Subsequent Event [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Number of pending claims | lawsuit	393
Number of plaintiffs | plaintiff	36,000
Sempra Mexico [Member] | Infraestructura Marina del Golfo [Member]
Loss Contingencies [Line Items]
Ownership percentage in equity method investee								40.00%
Sempra Mexico [Member] | Infraestructura Marina del Golfo [Member] | Corporate Joint Venture [Member]
Loss Contingencies [Line Items]
Ownership percentage in equity method investee								40.00%
Service Agreement, Term							25 years
Deferred Credits and Other [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs								$ 7,000,000