REVENUES - DISAGGREGATION OF REVENUE (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 2,348	$ 2,383	$ 7,479	$ 7,506
Utilities regulatory revenues	200	267	352	34
Other revenues	96	108	368	346
Total revenues	2,644	2,758	8,199	7,886
Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,101	2,131	6,847	6,774
Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	247	252	632	732
Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,077	1,029	4,171	4,112
Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,271	1,354	3,308	3,394
Operating Segments [Member] | San Diego Gas and Electric Company [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,301	1,370	3,610	3,604
Utilities regulatory revenues	171	57	366	62
Other revenues	0	0	0	0
Total revenues	1,472	1,427	3,976	3,666
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,301	1,370	3,610	3,604
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	126	100	518	441
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,175	1,270	3,092	3,163
Operating Segments [Member] | Southern California Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	813	765	3,261	3,170
Utilities regulatory revenues	29	210	(14)	(28)
Other revenues	0	0	0	0
Total revenues	842	975	3,247	3,142
Operating Segments [Member] | Southern California Gas Company [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	813	765	3,261	3,170
Operating Segments [Member] | Southern California Gas Company [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments [Member] | Southern California Gas Company [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	813	765	3,261	3,170
Operating Segments [Member] | Southern California Gas Company [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments [Member] | Sempra Mexico [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	256	256	658	757
Utilities regulatory revenues	0	0	0	0
Other revenues	95	101	277	301
Total revenues	351	357	935	1,058
Operating Segments [Member] | Sempra Mexico [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	12	14	42	56
Operating Segments [Member] | Sempra Mexico [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	244	242	616	701
Operating Segments [Member] | Sempra Mexico [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	159	171	439	527
Operating Segments [Member] | Sempra Mexico [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	97	85	219	230
Operating Segments [Member] | Sempra Renewables [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0		5
Utilities regulatory revenues		0		0
Other revenues		0		5
Total revenues		0		10
Operating Segments [Member] | Sempra Renewables [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0		0
Operating Segments [Member] | Sempra Renewables [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0		5
Operating Segments [Member] | Sempra Renewables [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0		0
Operating Segments [Member] | Sempra Renewables [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0		5
Operating Segments [Member] | Sempra LNG [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	35	50	56	139
Utilities regulatory revenues	0	0	0	0
Other revenues	28	50	199	188
Total revenues	63	100	255	327
Operating Segments [Member] | Sempra LNG [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Operating Segments [Member] | Sempra LNG [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	35	50	56	139
Operating Segments [Member] | Sempra LNG [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	33	48	51	134
Operating Segments [Member] | Sempra LNG [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2	2	5	5
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(57)	(58)	(106)	(169)
Utilities regulatory revenues	0	0	0	0
Other revenues	(27)	(43)	(108)	(148)
Total revenues	(84)	(101)	(214)	(317)
Consolidation, Eliminations [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(25)	(18)	(66)	(56)
Consolidation, Eliminations [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(32)	(40)	(40)	(113)
Consolidation, Eliminations [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(54)	(55)	(98)	(160)
Consolidation, Eliminations [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ (3)	$ (3)	$ (8)	$ (9)