NUCLEAR PLANT - REGULATORY ASSET (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	[1]
Regulatory Asset [Line Items]
Regulatory Assets, Noncurrent	$ 3,336	$ 3,273
San Diego Gas and Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets Current	119	107
Regulatory Assets, Noncurrent	968	977
Southern California Gas Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets Current	8	7
Regulatory Assets, Noncurrent	686	$ 636
Nuclear Plant Closure [Member]
Regulatory Asset [Line Items]
Regulatory Asset, Nuclear Plant Closure	243
Regulatory Assets Current	43
Regulatory Assets, Noncurrent	200
Nuclear Plant Closure [Member] | San Diego Gas and Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Asset, Nuclear Plant Closure	243
Regulatory Assets Current	43
Regulatory Assets, Noncurrent	$ 200

[1] Derived from audited financial statements.