SAN ONOFRE NUCLEAR GENERATING STATION (SONGS) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended		21 Months Ended
	Apr. 30, 2016	Oct. 31, 2015	Mar. 31, 2015	Sep. 30, 2016	Dec. 31, 2015		Sep. 30, 2016
Jointly Owned Utility Plant Interests [Line Items]
Regulatory asset, noncurrent				$ 3,424	$ 3,273	[1]	$ 3,424
Insurance recoveries		$ 400
Nuclear decommissioning trusts				1,068	1,063	[1]	1,068
Environmental exit costs, anticipated cost	$ 4,411
Authorized recovery amount, nuclear decommissioning trust funding				218			$ 218
Amount pending IRS clarification				$ 37
Ratepayers [Member]
Jointly Owned Utility Plant Interests [Line Items]
Insurance recoveries		75
San Diego Gas and Electric Company [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, proportionate ownership share				20.00%			20.00%
Loss from plant closure, after tax					125		$ 125
Adjustment to loss from plant closure, after tax			$ 13
Regulatory asset, current				$ 124	107	[1]	124
Regulatory asset, noncurrent				1,036	977	[1]	1,036
Insurance recoveries		$ 80
Nuclear decommissioning trusts				1,068	1,063	[1]	1,068
Environmental exit costs, anticipated cost	$ 899
Authorized recovery amount, nuclear decommissioning trust funding				218			218
San Diego Gas and Electric Company [Member] | Asset Retirement Obligation Costs [Member]
Jointly Owned Utility Plant Interests [Line Items]
Regulatory asset				195			195
Regulatory asset, current				45			45
Regulatory asset, noncurrent				150			150
Sempra Energy [Member]
Jointly Owned Utility Plant Interests [Line Items]
Loss from plant closure, after tax					$ 125		125
Adjustment to loss from plant closure, after tax			$ 13
Sempra Energy [Member] | Asset Retirement Obligation Costs [Member]
Jointly Owned Utility Plant Interests [Line Items]
Regulatory asset				195			195
Regulatory asset, current				45			45
Regulatory asset, noncurrent				$ 150			$ 150

[1] Derived from audited financial statements.