COMMITMENTS AND CONTINGENCIES - LEGAL PROCEEDINGS (Details)					1 Months Ended			3 Months Ended	6 Months Ended
	Aug. 03, 2017 plaintiff lawsuit	Jul. 19, 2017 Bcf	Mar. 13, 2017	Mar. 31, 2016 t	Feb. 28, 2017 USD ($)	Jan. 31, 2017 lawsuit	Sep. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Bcf lawsuit	Jun. 30, 2017 USD ($) Bcf lawsuit	Dec. 31, 2016 USD ($)	[1]	Oct. 21, 2016 t
Loss Contingencies [Line Items]
Percent of arbitration expenses reduction of award			95.00%
Reserve for Aliso Canyon costs								$ 63,000,000	$ 63,000,000	$ 53,000,000
Insurance receivable for Aliso Canyon costs								554,000,000	554,000,000	606,000,000
Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs								63,000,000	63,000,000
Insurance receivable for Aliso Canyon costs								$ 554,000,000	$ 554,000,000
Property Disputes [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit									2
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]
Settlement to be paid					$ 8,500,000
Number of lawsuits filed | lawsuit								3
Complaints Filed by Public Entities [Member] | Health Study [Member]
Loss Contingencies [Line Items]
Settlement to be paid					$ 1,000,000
Legal Reserves [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								$ 10,000,000	$ 10,000,000
Legal Reserves [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								5,000,000	5,000,000
San Diego Gas and Electric Company [Member] | Wildfire [Member]
Loss Contingencies [Line Items]
Regulatory assets arising from wildfire litigation costs								350,000,000	350,000,000
Potential after-tax charge for nonrecovery of CPUC regulatory assets								207,000,000	207,000,000
San Diego Gas and Electric Company [Member] | Lawsuit Against MHI [Member]
Loss Contingencies [Line Items]
Percent of arbitration expenses reduction of award			95.00%
San Diego Gas and Electric Company [Member] | Legal Reserves [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								3,000,000	3,000,000
Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs								63,000,000	63,000,000	53,000,000
Insurance receivable for Aliso Canyon costs								554,000,000	554,000,000	$ 606,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								832,000,000	832,000,000
Reserve for Aliso Canyon costs								63,000,000	63,000,000
Insurance receivable for Aliso Canyon costs								$ 554,000,000	554,000,000
Insurance proceeds									$ 273,000,000
Period of required climate reductions				20 years
Period of required regulatory climate reductions				100 years
Target emissions level (in metric tons) | t				9,000,000
Loss Contingency, Total Actual Emissions, Floor (in metric tons) | t												90,350
Loss Contingency, Total Actual Emissions, Ceiling (in metric tons) | t												108,950
Mitigation requirements (in metric tons) | t												109,000
Amount of natural gas released | Bcf									4.62
Storage facility capacity | Bcf								86	86
Proportion of total gas storage capacity (percentage)								63.00%	63.00%
Net book value of Aliso Canyon facility								$ 582,000,000	$ 582,000,000
Construction work in progress of new compressor station								237,000,000	237,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit	281
Number of plaintiffs | plaintiff	25,500
Required working gas target | Bcf		23.6
Required working gas minimum | Bcf		14.8
Proportion of total gas storage capacity (percentage)		28.00%
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
Environmental mitigation period				5 years
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
Environmental mitigation period				10 years
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							$ 5,000,000
Southern California Gas Company [Member] | Legal Reserves [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								5,000,000	5,000,000
Southern California Gas Company [Member] | Legal Reserves [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								$ 5,000,000	$ 5,000,000

[1] Derived from audited financial statements.