SAN ONOFRE NUCLEAR GENERATING STATION - ASSET RETIREMENT OBLIGATION AND SPENT NUCLEAR FUEL (Details) - San Diego Gas and Electric Company [Member] $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Decommissioning liability	$ 611
Cost study estimate decommissioning escalated	834
2020	89
2021	82
2022	83
2023	63
2024	46
Thereafter	$ 739