QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Line Items]
Quarterly Financial Data, Revenues	$ 2,964,000,000	$ 2,679,000,000	$ 2,533,000,000	$ 3,031,000,000	$ 2,870,000,000	$ 2,535,000,000	$ 2,156,000,000	$ 2,622,000,000
Quarterly Financial Data, Expenses And Other Income	2,564,000,000	2,664,000,000	2,118,000,000	2,276,000,000	2,365,000,000	1,553,000,000	2,268,000,000	2,167,000,000
Quarterly Financial Data, Net Income (Loss)	(451,000,000)	102,000,000	248,000,000	452,000,000	409,000,000	719,000,000	27,000,000	364,000,000
Earnings	$ (501,000,000)	$ 57,000,000	$ 259,000,000	$ 441,000,000	$ 379,000,000	$ 622,000,000	$ 16,000,000	$ 353,000,000	$ 256,000,000	$ 1,370,000,000	$ 1,349,000,000
Quarterly Financial Data, Net Income Per Share, Basic (in dollars per share)	$ (1.80)	$ 0.41	$ 0.99	$ 1.80	$ 1.63	$ 2.87	$ 0.11	$ 1.46
Basic earnings per common share (in dollars per share)	$ (1.99)	$ 0.23	$ 1.03	$ 1.76	$ 1.51	$ 2.48	$ 0.06	$ 1.41	$ 1.02	$ 5.48	$ 5.43
Weighted-average number of shares outstanding, basic	251,900	251,700	251,400	251,100	250,600	250,400	250,100	249,700	251,545	250,217	248,249
Quarterly Financial Data, Net Income Per Share, Diluted (in dollars per share)	$ (1.80)	$ 0.41	$ 0.98	$ 1.79	$ 1.62	$ 2.85	$ 0.11	$ 1.45
Diluted earnings per common share (in dollars per share)	$ (1.99)	$ 0.22	$ 1.03	$ 1.75	$ 1.51	$ 2.46	$ 0.06	$ 1.40	$ 1.01	$ 5.46	$ 5.37
Weighted-average number of shares outstanding, diluted	251,900	253,400	252,800	252,200	251,600	252,400	252,000	251,500	252,300	251,155	250,923
Antidilutive securities excluded from the computation of EPS	800
San Diego Gas and Electric Company [Member]
Selected Quarterly Financial Information [Line Items]
Quarterly Financial Data, Revenues	$ 1,125,000,000	$ 1,236,000,000	$ 1,058,000,000	$ 1,057,000,000	$ 1,061,000,000	$ 1,209,000,000	$ 992,000,000	$ 991,000,000
Quarterly Financial Data, Operating Expenses	877,000,000	1,290,000,000	817,000,000	779,000,000	800,000,000	886,000,000	822,000,000	755,000,000
Quarterly Financial Data, Operating Income	248,000,000	(54,000,000)	241,000,000	278,000,000	261,000,000	323,000,000	170,000,000	236,000,000
Quarterly Financial Data, Net Income (Loss)	130,000,000	(19,000,000)	153,000,000	157,000,000	147,000,000	194,000,000	87,000,000	137,000,000
Quarterly Financial Data, (Earnings) Losses Attributable To Noncontrolling Interests	(1,000,000)	9,000,000	4,000,000	2,000,000	(4,000,000)	11,000,000	(13,000,000)	1,000,000
Quarterly Financial Data, Earnings Attributable To Common Shares	131,000,000	(28,000,000)	149,000,000	155,000,000	151,000,000	183,000,000	100,000,000	136,000,000
Southern California Gas Company [Member]
Selected Quarterly Financial Information [Line Items]
Quarterly Financial Data, Revenues	1,090,000,000	684,000,000	770,000,000	1,241,000,000	1,135,000,000	686,000,000	617,000,000	1,033,000,000
Quarterly Financial Data, Operating Expenses	888,000,000	674,000,000	675,000,000	926,000,000	899,000,000	648,000,000	628,000,000	739,000,000
Quarterly Financial Data, Operating Income	202,000,000	10,000,000	95,000,000	315,000,000	236,000,000	38,000,000	(11,000,000)	294,000,000
Quarterly Financial Data, Net Income (Loss)	128,000,000	7,000,000	59,000,000	203,000,000	151,000,000	0	0	199,000,000
Quarterly Financial Data, Dividends On Preferred Stock	0	0	1,000,000	0	0	0	1,000,000	0
Quarterly Financial Data, Earnings Attributable To Common Shares	$ 128,000,000	$ 7,000,000	$ 58,000,000	$ 203,000,000	$ 151,000,000	$ 0	$ (1,000,000)	$ 199,000,000