SAN ONOFRE NUCLEAR GENERATING STATION - NARRATIVE (Details) - USD ($) $ in Millions		12 Months Ended
	Mar. 13, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 19, 2017
Jointly Owned Utility Plant Interests [Line Items]
Litigation settlement payable	$ 24
Percent of arbitration expenses awarded	95.00%
Settlement payable net of arbitration expense	$ 60
Regulatory asset, current		$ 222	$ 138
Regulatory asset, noncurrent		$ 1,930	1,589
Period of environmental exit		10 years
San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Litigation settlement payable	118
Settlement payable net of arbitration expense	12
Arbitration expense	12
Legal fees	11
Litigation settlement amount allocated to ratepayers and shareholders	$ 1
Regulatory asset threshold to cease rate recovery				$ 152
Regulatory asset, current		$ 209	123
Regulatory asset, noncurrent		$ 440	$ 454
Percentage of environmental exit costs incurred		20.00%
San Diego Gas and Electric Company [Member] | Nuclear Plant Closure [Member]
Jointly Owned Utility Plant Interests [Line Items]
Regulatory asset threshold to cease rate recovery				$ 775
Receivable for nuclear plant closure		$ 86
Regulatory asset, current		38
Regulatory asset, noncurrent		$ 48
San Diego Gas and Electric Company [Member] | San Onofre Nuclear Generating Station (SONGS) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership percentage		20.00%
SONGS 1 Decommissioning [Member] | San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Nuclear decommissioning trust authorized withdrawal amount		$ 455
SONGS 2 and 3 Decommissioning [Member] | San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Nuclear decommissioning trust authorized withdrawal amount		$ 109