GENERAL INFORMATION AND OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (259)	$ (264)	$ (776)	$ (818)
Equity earnings	391	326	1,022	822
Energy-related businesses	453	343	1,174	1,000
Other Income (Expense), Net	55	(29)	(52)	163
(Loss) income from continuing operations before income taxes and equity earnings	(1,365)	201	(316)	1,061
(Losses) earnings from discontinued operations attributable to Sempra	0	(7)	0	1,840
Income tax benefit (expense)	342	(99)	45	(60)
Net (loss) income	(632)	421	751	3,673
Earnings attributable to noncontrolling interest	(5)	(22)	(48)	(201)
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(104)	(103)	(307)	(307)
Other Income (Expense), Net	(4)	2	(61)	(47)
(Loss) income from continuing operations before income taxes and equity earnings	295	211	771	794
Income tax benefit (expense)	(90)	(33)	(168)	(161)
Net (loss) income			603	633
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(39)	(39)	(118)	(119)
Other Income (Expense), Net	39	7	2	(21)
(Loss) income from continuing operations before income taxes and equity earnings	(1,563)	(30)	(959)	521
Income tax benefit (expense)	437	6	335	(95)
Net (loss) income	(1,126)	(24)	(624)	426
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	19	16	57	696
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	1	0	1	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	0	2	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign currency translation adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Losses) earnings from discontinued operations attributable to Sempra			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]
(Loss) income from continuing operations before income taxes and equity earnings	23	4	63	43
Income tax benefit (expense)	(7)	0	(16)	(12)
Net (loss) income			47	31
Earnings attributable to common shares	16	4	45	25
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)	3	0	6
Equity earnings	19	5	57	8
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)
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
Other Income (Expense), Net	5	(4)	4	33
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			(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	3	3	6	6
(Losses) earnings from discontinued operations attributable to Sempra			0	6
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Pension and Other Postretirement Benefits [Member] | Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (Expense), Net	1	0	1	0
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	3	3
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 (Expense), Net	1	0	1	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 (Expense), Net			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	13	7	22
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and Other Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Loss) income from continuing operations before income taxes and equity earnings	4	17	16	37
(Losses) earnings from discontinued operations attributable to Sempra			0	(2)
Income tax benefit (expense)	(1)	(5)	(4)	(9)
Net (loss) income	$ 3	$ 12	$ 12	$ 26