SAN ONOFRE NUCLEAR GENERATING STATION (Details) - USD ($) $ in Millions		1 Months Ended	9 Months Ended
	Mar. 13, 2017	Apr. 30, 2016	Sep. 30, 2017	Feb. 28, 2017	Dec. 31, 2016	[1]
Jointly Owned Utility Plant Interests [Line Items]
Settlement amount awarded	$ 118
Percent of arbitration expenses reduction of award	95.00%
Settlement amount net of arbitration expense	$ 60
Regulatory asset, noncurrent			$ 3,186		$ 3,414
Anticipated term of dismantlement work			10 years
Nuclear decommissioning trusts			$ 1,041		1,026
Environmental exit costs, anticipated cost		$ 4,400
San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Settlement amount awarded	24
Settlement amount net of arbitration expense	12
Arbitration expense	12
Legal costs	11
Litigation settlement amount allocated to ratepayers and shareholders	$ 1
Regulatory asset, current			112		81
Regulatory asset, noncurrent			$ 572		998
Regulatory Asset, Amortization Period			10 years
Percent of dismantlement work expense			20.00%
Nuclear decommissioning trusts			$ 1,041		$ 1,026
Environmental exit costs, anticipated cost		$ 899
Authorized recovery amount, nuclear decommissioning trust funding			302	$ 84
San Diego Gas and Electric Company [Member] | Asset Retirement Obligation Costs [Member]
Jointly Owned Utility Plant Interests [Line Items]
Regulatory asset			158
Regulatory asset, current			35
Regulatory asset, noncurrent			$ 123
Jointly Owned Nuclear Power Plant [Member] | San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, proportionate ownership share			20.00%
Loss from plant closure, after tax			$ 125

[1] Derived from audited financial statements.