GENERAL INFORMATION AND OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (258)	$ (274)	$ (517)	$ (554)
Equity earnings	313	233	631	496
Energy-related businesses	307	293	721	657
Other Income (Expense), Net	(72)	(62)	(107)	192
Income from continuing operations before income taxes and equity earnings	281	463	1,049	860
Earnings from discontinued operations attributable to Sempra	0	1,775	0	1,847
Income tax (expense) benefit	(139)	(168)	(297)	39
Net income	455	2,305	1,383	3,252
Earnings attributable to noncontrolling interest	(10)	(28)	(43)	(179)
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(101)	(103)	(203)	(204)
Other Income (Expense), Net	(22)	(18)	(57)	(49)
Income from continuing operations before income taxes and equity earnings	219	263	476	583
Income tax (expense) benefit	(33)	(70)	(78)	(128)
Net income			398	455
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(40)	(40)	(79)	(80)
Other Income (Expense), Net	2	2	(37)	(28)
Income from continuing operations before income taxes and equity earnings	103	196	604	551
Income tax (expense) benefit	(8)	(49)	(102)	(101)
Net income	95	147	502	450
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	12	655	38	680
Reclassification out of Accumulated Other Comprehensive Income [Member] | San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	0	1	0	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	1	1	1	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign currency translation adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from discontinued operations attributable to Sempra	0	645	0	645
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes and equity earnings	11	0	40	39
Income tax (expense) benefit	(1)	0	(9)	(12)
Net income	10	0	31	27
Earnings attributable to common shares	10	2	29	21
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(1)	1	1	3
Equity earnings	19	1	38	3
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Equity earnings			1	(2)
Energy-related businesses			1	(2)
Other Income (Expense), Net	0	1	0	(1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Interest rate and foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	0	1	0	1
Other Income (Expense), Net	(7)	(4)	(1)	37
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Noncontrolling Interests [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to noncontrolling interest	0	2	(2)	(6)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (Expense), Net	1	1	3	3
Earnings from discontinued operations attributable to Sempra	0	6	0	6
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (Expense), Net	1	1	2	2
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] | San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income, Net	0	1	0	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] | Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income, Net	1	1	1	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Settlements Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (Expense), Net	0	4	7	9
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes and equity earnings	2	12	12	20
Earnings from discontinued operations attributable to Sempra	0	(2)	0	(2)
Income tax (expense) benefit	0	(2)	(3)	(4)
Net income	$ 2	$ 8	$ 9	$ 14