REVENUES - DISAGGREGATION OF REVENUE (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 3,141	$ 3,007
Utilities regulatory revenues	(28)	(139)
Other revenues	146	161
Total revenues	3,259	3,029
Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,873	2,804
Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	268	203
Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,118	1,933
Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,023	1,074
Operating Segments [Member] | San Diego Gas and Electric Company [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,216	1,259
Utilities regulatory revenues	121	10
Other revenues	0	0
Total revenues	1,337	1,269
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,216	1,259
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
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	273	254
Operating Segments [Member] | San Diego Gas and Electric Company [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	943	1,005
Operating Segments [Member] | Southern California Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,657	1,544
Utilities regulatory revenues	(149)	(149)
Other revenues	0	0
Total revenues	1,508	1,395
Operating Segments [Member] | Southern California Gas Company [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,657	1,544
Operating Segments [Member] | Southern California Gas Company [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Operating Segments [Member] | Southern California Gas Company [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,657	1,544
Operating Segments [Member] | Southern California Gas Company [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Operating Segments [Member] | Sempra Mexico [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	308	218
Utilities regulatory revenues	0	0
Other revenues	59	91
Total revenues	367	309
Operating Segments [Member] | Sempra Mexico [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	27	20
Operating Segments [Member] | Sempra Mexico [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	281	198
Operating Segments [Member] | Sempra Mexico [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	224	147
Operating Segments [Member] | Sempra Mexico [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	84	71
Operating Segments [Member] | Sempra LNG [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	68	12
Utilities regulatory revenues	0	0
Other revenues	128	111
Total revenues	196	123
Operating Segments [Member] | Sempra LNG [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Operating Segments [Member] | Sempra LNG [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	68	12
Operating Segments [Member] | Sempra LNG [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	67	11
Operating Segments [Member] | Sempra LNG [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	1
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(108)	(26)
Utilities regulatory revenues	0	0
Other revenues	(41)	(41)
Total revenues	(149)	(67)
Consolidation, Eliminations [Member] | Utilities service line [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(27)	(19)
Consolidation, Eliminations [Member] | Energy-Related Businesses [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(81)	(7)
Consolidation, Eliminations [Member] | Gas market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(103)	(23)
Consolidation, Eliminations [Member] | Electric market [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ (5)	$ (3)