REGULATORY MATTERS - GENERAL RATE CASE (Details) - USD ($) $ in Millions			9 Months Ended
	Sep. 26, 2019	Oct. 06, 2017	Sep. 30, 2019	Dec. 31, 2018	[1]
General Rate Case [Line Items]
Regulatory assets, noncurrent			$ 1,942	$ 1,589
San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
Regulatory assets, noncurrent			519	454
GRC requested revenue requirement		$ 2,203
General Rate Case, Retroactive Impact, Incremental Earnings			(92)
General Rate Case, Retroactive Impact, Incremental Earnings, Net Of Tax			66
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			79
Southern California Gas Company [Member]
General Rate Case [Line Items]
Regulatory assets, noncurrent			1,341	$ 1,051
GRC requested revenue requirement		$ 2,937
General Rate Case, Retroactive Impact, Incremental Earnings			(181)
General Rate Case, Retroactive Impact, Incremental Earnings, Net Of Tax			130
Southern California Gas Company [Member] | General Rate Case [Member]
General Rate Case [Line Items]
Tracked income tax expense liability			88
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]
Regulatory assets			81
Regulatory assets, noncurrent			51
GRC requested revenue requirement	$ 1,990
Difference from requested amount	213
Revenue increase	$ 107
Percent increase	5.70%
2019 GRC FD [Member] | Southern California Gas Company [Member]
General Rate Case [Line Items]
Regulatory assets			286
Regulatory assets, noncurrent			$ 179
GRC requested revenue requirement	$ 2,770
Difference from requested amount	167
Revenue increase	$ 314
Percent increase	12.80%
2019 GRC FD [Member] | Electric market [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement	$ 1,590
2019 GRC FD [Member] | Gas market [Member] | San Diego Gas and Electric Company [Member]
General Rate Case [Line Items]
GRC requested revenue requirement	$ 400

[1] Derived from audited financial statements.