COMMITMENTS AND CONTINGENCIES - LEGAL PROCEEDINGS (Details)		1 Months Ended			3 Months Ended		4 Months Ended	9 Months Ended
	Oct. 28, 2019 plaintiff lawsuit	Aug. 31, 2018 USD ($)	Jan. 31, 2017 lawsuit	Feb. 29, 2016 USD ($)	Sep. 30, 2019 USD ($) Bcf lawsuit	Sep. 30, 2017 USD ($)	Jan. 31, 2019 plaintiff	Sep. 30, 2019 USD ($) Bcf	Dec. 31, 2018 USD ($)	[1]
Loss Contingencies [Line Items]
Liability for legal proceedings					$ 97,000,000			$ 97,000,000
Reserve for Aliso Canyon costs					$ 45,000,000			45,000,000	$ 160,000,000
Consolidated Class Action Complaints [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit			2
Property Class Action [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit			1
Complaints Filed by Public Entities [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit					3
Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Liability for legal proceedings					$ 50,000,000			50,000,000
Insurance settlements receivable					1,069,000,000			1,069,000,000
Reserve for Aliso Canyon costs					45,000,000			45,000,000	$ 160,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Liability for legal proceedings					49,000,000			49,000,000
Loss contingency accrual					$ 1,099,000,000			$ 1,099,000,000
Percent of loss accrual allocated to temporary relocation program					52.00%			52.00%
Receivable related to natural gas leak					$ 354,000,000			$ 354,000,000
Reserve for Aliso Canyon costs					45,000,000			45,000,000
Payable related to natural gas leak, noncurrent					$ 9,000,000			9,000,000
Insurance proceeds								$ 715,000,000
Storage facility capacity | Bcf					86			86
Proportion of total gas storage capacity (percentage)					63.00%			63.00%
Working gas target | Bcf					34			34
Net book value of Aliso Canyon facility					$ 771,000,000			$ 771,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Liability insurance coverage					1,200,000,000			1,200,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Liability insurance coverage					1,400,000,000			1,400,000,000
Southern California Gas Company [Member] | Damages from Product Defects [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
Southern California Gas Company [Member] | Complaints Filed by Firefighters [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff							51
Southern California Gas Company [Member] | Complaints Filed by Public Entities [Member] | Funding for Environmental Projects [Member]
Loss Contingencies [Line Items]
Settlement amount payable		$ 120,000,000
Southern California Gas Company [Member] | Complaints Filed by Public Entities [Member] | Civil Penalties [Member]
Loss Contingencies [Line Items]
Settlement amount payable		$ 21,000,000
San Diego Gas and Electric Company [Member] | Wildfire [Member]
Loss Contingencies [Line Items]
Write-off of wildfire regulatory asset						$ 351,000,000
After-tax charge for nonrecovery of CPUC regulatory assets						$ 208,000,000
Sempra Energy [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs					45,000,000			45,000,000
Payable related to natural gas leak, noncurrent					$ 9,000,000			$ 9,000,000
IMG [Member] | Corporate Joint Venture [Member] | Sempra Mexico [Member]
Loss Contingencies [Line Items]
Interest percentage					40.00%			40.00%
Service agreement term								25 years
Subsequent Event [Member] | Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit	390
Number of plaintiffs | plaintiff	36,000
Subsequent Event [Member] | Energy Future Holdings Corp. [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit	103
Number of lawsuits filed | lawsuit	1,608

[1] Derived from audited financial statements.