REGULATORY MATTERS - GENERAL RATE CASE (Details) - USD ($) $ in Millions		1 Months Ended		3 Months Ended	12 Months Ended
	Oct. 06, 2017	Apr. 30, 2018	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2018
San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement	$ 2,203				$ 1,918
GRC revenue requirement decrease		$ 64
GRC revenue requirement adjustment increase	221
Tax Cuts and Jobs Act, change in tax rate, change in revenue requirement		$ 58
General rate case, proposed annual attrition percent		4.00%
Adjustment to revenue related to tax repairs deductions, pre-tax				$ 52
Adjustment to revenue related to tax repairs deductions, net of tax				31
San Diego Gas and Electric Company [Member] | Year 2016 [Member]
General Rate Case [Line Items]
GRC revenue requirement			$ 1,791
San Diego Gas and Electric Company [Member] | General Rate Case [Member]
General Rate Case [Line Items]
Tracked income tax expense liability					89
San Diego Gas and Electric Company [Member] | Future Refund of Rates to Customers [Member]
General Rate Case [Line Items]
Regulatory liability					75
San Diego Gas and Electric Company [Member] | Future Refund of Rates to Customers - FERC [Member]
General Rate Case [Line Items]
Regulatory liability					67
Southern California Gas Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement	2,937				2,695
GRC revenue requirement decrease		$ 239
GRC revenue requirement adjustment increase	$ 481
Tax Cuts and Jobs Act, change in tax rate, change in revenue requirement		$ 58
Adjustment to revenue related to tax repairs deductions, pre-tax				83
Adjustment to revenue related to tax repairs deductions, net of tax				$ 49
Southern California Gas Company [Member] | Year 2016 [Member]
General Rate Case [Line Items]
GRC revenue requirement			$ 2,204
Southern California Gas Company [Member] | General Rate Case [Member]
General Rate Case [Line Items]
Tracked income tax expense liability					94
Southern California Gas Company [Member] | Future Refund of Rates to Customers [Member]
General Rate Case [Line Items]
Regulatory liability					$ 68
Minimum [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement adjustment percentage	5.00%
Minimum [Member] | Southern California Gas Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement adjustment percentage	6.00%
General rate case, proposed annual attrition percent		4.00%
Maximum [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement adjustment percentage	7.00%
Maximum [Member] | Southern California Gas Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement adjustment percentage	8.00%
General rate case, proposed annual attrition percent		5.00%
Otay Mesa Energy Center [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
Operating expenses		$ 68