GENERAL INFORMATION AND OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (264)	$ (279)	$ (818)	$ (797)
(Loss) Income from Discontinued Operations, Net of Income Tax	(7)	248	1,840	267
Other Income (Expense), Net	(29)	7	163	(103)
(Loss) gain on sale of assets	0	(3)	0	63
Equity earnings	326	266	822	485
Energy-related businesses	343	360	1,000	1,078
Income from continuing operations before income taxes and equity earnings	201	448	1,061	1,235
Income tax expense	(99)	(61)	(60)	(150)
Net income	421	909	3,673	1,862
Earnings attributable to noncontrolling interest	(22)	(60)	(201)	(146)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	16	9	696	35
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign currency translation adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Loss) Income from Discontinued Operations, Net of Income Tax			645	0
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	4	8	43	16
Income tax expense	0	(2)	(12)	(3)
Net income	4	6	31	13
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	3	1	7	2
Other Income (Expense), Net	(4)	5	33	0
Equity earnings	5	2	6	3
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]
(Loss) gain on sale of assets			0	10
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]
Other Income (Expense), Net			(1)	0
Energy-related businesses			(2)	1
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)	(6)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	4	4	25	10
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]
(Loss) Income from Discontinued Operations, Net of Income Tax			6	0
Other Income (Expense), Net	3	3	6	7
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	2
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	13	4	22	26
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 Discontinued Operations, Net of Income Tax			(2)	0
Income from continuing operations before income taxes and equity earnings	17	8	37	35
Income tax expense	(5)	(3)	(9)	(10)
Net income	12	5	26	25
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(103)	(106)	(307)	(311)
Other Income (Expense), Net	2	(19)	(47)	(60)
Income from continuing operations before income taxes and equity earnings	211	337	794	700
Income tax expense	(33)	(71)	(161)	(111)
Net income	178	266	633	589
Earnings attributable to noncontrolling interest	0	(3)	0	(7)
San Diego Gas and Electric Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	0	0	1	1
San Diego Gas and Electric Company [Member] | 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	0	1	0	3
San Diego Gas and Electric Company [Member] | 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	(1)	0	(3)
San Diego Gas and Electric Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares			0	0
San Diego Gas and Electric Company [Member] | 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, Net			1	1
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(39)	(36)	(119)	(104)
Other Income (Expense), Net	7	(1)	(21)	(18)
Income from continuing operations before income taxes and equity earnings	(30)	178	521	488
Income tax expense	6	(35)	(95)	(50)
Net income	(24)	143	426	438
Southern California Gas Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	0	1	1	1
Southern California Gas Company [Member] | 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	$ 0	$ 1	0	1
Southern California Gas Company [Member] | 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, Net			$ 1	$ 0