COMMITMENTS AND CONTINGENCIES - LEGAL PROCEEDINGS (Details)					1 Months Ended			3 Months Ended
		May 08, 2017 plaintiff lawsuit	Mar. 13, 2017 USD ($)	Mar. 31, 2016 t	Feb. 28, 2017 USD ($)	Jan. 31, 2017 lawsuit	Sep. 30, 2016 USD ($)	Mar. 31, 2017 USD ($) Bcf lawsuit	Dec. 31, 2016 USD ($)		Oct. 21, 2016 t
Loss Contingencies [Line Items]
Percent of arbitration expenses reduction of award			95.00%
Settlement credit to ratepayers			$ 118,000,000
Reserve for Aliso Canyon costs	[1]								$ 53,000,000
Insurance receivable for Aliso Canyon costs								$ 621,000,000	606,000,000	[1]
Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs								49,000,000
Insurance receivable for Aliso Canyon costs								$ 621,000,000
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 credit to ratepayers					$ 8,500,000
Number of lawsuits filed | lawsuit								3
Complaints Filed by Public Entities [Member] | Health Study [Member]
Loss Contingencies [Line Items]
Settlement credit to ratepayers					$ 1,000,000
Legal Reserves [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								$ 18,000,000
Legal Reserves [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								5,000,000
San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Settlement credit to ratepayers			$ 24,000,000
San Diego Gas and Electric Company [Member] | Wildfire [Member]
Loss Contingencies [Line Items]
Regulatory assets arising from wildfire litigation costs								350,000,000
Portion of regulatory assets arising from wildfire litigation related to CPUC operations								349,000,000
Portion of regulatory assets arising from wildfire litigation related to FERC operations								1,000,000
Potential after-tax charge for nonrecovery of CPUC regulatory assets								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								11,000,000
Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Reserve for Aliso Canyon costs								49,000,000	53,000,000	[1]
Insurance receivable for Aliso Canyon costs								621,000,000	$ 606,000,000	[1]
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								$ 799,000,000
Estimated costs related to temporary relocation (percentage)								70.00%
Estimated costs related to controlling well and stopping leak and emissions (percentage)								20.00%
Reserve for Aliso Canyon costs								$ 49,000,000
Insurance receivable for Aliso Canyon costs								621,000,000
Insurance proceeds								$ 173,000,000
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
Proportion of total gas storage capacity (percentage)								63.00%
Net book value of Aliso Canyon facility								$ 550,000,000
Construction work in progress of new compressor station								225,000,000
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		266
Number of plaintiffs | plaintiff		22,000
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
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
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							$ 4,000,000
Southern California Gas Company [Member] | Legal Reserves [Member]
Loss Contingencies [Line Items]
Loss contingency accrual								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

[1] Derived from audited financial statements.