COMMITMENTS AND CONTINGENCIES - LEGAL PROCEEDINGS (Details)						3 Months Ended	9 Months Ended	11 Months Ended
	Nov. 01, 2016 plaintiff lawsuit	Apr. 05, 2016 plaintiff	Mar. 31, 2016 t	Feb. 16, 2016 USD ($)	Jan. 23, 2016	Sep. 30, 2016 USD ($) Bcf	Sep. 30, 2016 USD ($) Bcf appeal	Sep. 30, 2016 USD ($) Bcf	Oct. 21, 2016 t	Sep. 28, 2016 well MMcf	Jun. 28, 2016 well Bcf	Jan. 31, 2016 Bcf	Dec. 31, 2015 USD ($)	[1]	Oct. 23, 2015 Bcf
Loss Contingencies [Line Items]
Loss contingency accrual						$ 23,000,000	$ 23,000,000	$ 23,000,000
Reserve for Aliso Canyon costs						73,000,000	73,000,000	73,000,000					$ 274,000,000
Insurance receivable for Aliso Canyon costs						664,000,000	664,000,000	664,000,000					325,000,000
San Diego Gas and Electric Company [Member]
Loss Contingencies [Line Items]
Loss contingency accrual						21,000,000	$ 21,000,000	21,000,000
San Diego Gas and Electric Company [Member] | Wildfire [Member]
Loss Contingencies [Line Items]
Number of appeals pending | appeal							1
Regulatory assets arising from wildfire litigation costs						356,000,000	$ 356,000,000	356,000,000
Portion of regulatory assets arising from wildfire litigation related to CPUC operations						354,000,000	354,000,000	354,000,000
Potential after-tax charge for nonrecovery of CPUC regulatory assets						210,000,000	210,000,000	210,000,000
San Diego Gas and Electric Company [Member] | Wind Farm [Member]
Loss Contingencies [Line Items]
Estimated tax equity investment						285,000,000	285,000,000	285,000,000
Settlement credit to ratepayers							39,000,000
Southern California Gas Company [Member]
Loss Contingencies [Line Items]
Loss contingency accrual						1,000,000	1,000,000	1,000,000
Reserve for Aliso Canyon costs						73,000,000	73,000,000	73,000,000					274,000,000
Insurance receivable for Aliso Canyon costs						664,000,000	664,000,000	664,000,000					$ 325,000,000
Southern California Gas Company [Member] | Aliso Canyon Natural Gas Storage Facility Gas Leak [Member]
Loss Contingencies [Line Items]
Loss contingency accrual						$ 763,000,000	$ 763,000,000	$ 763,000,000
Estimated costs related to temporary relocation (percentage)						70.00%	70.00%	70.00%
Estimated costs related to controlling well and stopping leak and emissions (percentage)						20.00%	20.00%	20.00%
Increase in reserve						$ 46,000,000
Insurance proceeds							$ 94,000,000
Number of plaintiffs | plaintiff		24
Total penalties							$ 60,800
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
Environmental monitoring period					30 days
Estimated withdrawal capacity required to meet customer reliability needs (in Bcf) | Bcf											1,119,000,000
Number of wells required to be kept available for reliability related withdrawals | well										17	17
Required minimum hourly withdrawal capacity (in cubic feet) | MMcf										8,600,000
Required minimum daily withdrawal capacity (in cubic feet) | MMcf										207
Amount of natural gas delivered | Bcf								57
Amount of natural gas in storage | Bcf															77
Amount of natural gas released | Bcf								4.62
Amount of natural gas to be retained in storage | Bcf												15
Storage facility capacity | Bcf						86	86	86
Proportion of total gas storage capacity (percentage)						63.00%	63.00%	63.00%
Net book value of Aliso Canyon facility						$ 491,000,000	$ 491,000,000	$ 491,000,000
Construction work in progress of new compressor station						217,000,000	217,000,000	217,000,000
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	212
Number of plaintiffs | plaintiff	12,000
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
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	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	$ 1,400,000,000
Environmental mitigation period			10 years
Southern California Gas Company [Member] | South Coast Air Quality Management District [Member]
Loss Contingencies [Line Items]
Civil penalties per day							$ 250,000
Southern California Gas Company [Member] | Damages from Product Defects [Member]
Loss Contingencies [Line Items]
Maximum occupational safety and health fines				$ 75,000
Penalty assessments				232,500
Maximum other assessments in settlement of criminal complaint				$ 4,000,000
Southern California Gas Company [Member] | So Cal Gas PCB Litigation [Member]
Loss Contingencies [Line Items]
Number of lawsuits filed							7
Number of lawsuits settled							6

[1] Derived from audited financial statements.