REGULATORY MATTERS - GENERAL RATE CASE (Details) - USD ($) $ in Millions	Sep. 26, 2019	Oct. 06, 2017	Dec. 31, 2019	Dec. 31, 2018
General Rate Case [Line Items]
Regulatory assets, noncurrent			$ 1,930	$ 1,589
San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement		$ 2,203
Regulatory assets, noncurrent			440	454
San Diego Gas and Electric Company [Member] | General Rate Case [Member]
General Rate Case [Line Items]
Tracked income tax expense liability				86
San Diego Gas and Electric Company [Member] | Future Refund of Rates to Customers [Member]
General Rate Case [Line Items]
Regulatory liability			88
San Diego Gas and Electric Company [Member] | Future Refund of Rates to Customers - FERC [Member]
General Rate Case [Line Items]
Regulatory liability			66
Southern California Gas Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement		$ 2,937
Regulatory assets, noncurrent			1,407	1,051
Southern California Gas Company [Member] | General Rate Case [Member]
General Rate Case [Line Items]
Tracked income tax expense liability				$ 89
Southern California Gas Company [Member] | Future Refund of Rates to Customers [Member]
General Rate Case [Line Items]
Regulatory liability			75
2019 GRC FD [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC revenue requirement	$ 1,990
General Rate Case, Revenue Requirement, Difference From Requested Amount	213
Revenue increase	$ 107
Percent increase	5.70%
Regulatory assets			111
Regulatory assets, noncurrent			56
2019 GRC FD [Member] | Southern California Gas Company [Member]
General Rate Case [Line Items]
GRC revenue requirement	$ 2,770
General Rate Case, Revenue Requirement, Difference From Requested Amount	167
Revenue increase	$ 314
Percent increase	12.80%
Regulatory assets			400
Regulatory assets, noncurrent			$ 200
Electricity [Member] | 2019 GRC FD [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC revenue requirement	$ 1,590
Natural Gas, Gathering, Transportation, Marketing and Processing [Member] | 2019 GRC FD [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC revenue requirement	$ 400