GENERAL INFORMATION AND OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (258)	$ (228)	$ (518)	$ (434)
Other income, net	(28)	56	(110)	(96)
Gain on sale of assets	66	0	66	0
Equity earnings (losses)	118	(4)	219	(25)
Energy-related businesses	335	355	718	701
Income (loss) from continuing operations before income taxes and equity earnings (losses)	286	(1,183)	787	(590)
Income tax (expense) benefit	(47)	602	(89)	360
Net income	(435)	530	(953)	172
Earnings attributable to noncontrolling interest	(45)	(5)	(86)	12
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
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	25	10	26	4
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before income taxes and equity earnings (losses)	8	19	8	3
Income tax (expense) benefit	(1)	(4)	(1)	(1)
Net income	7	15	7	2
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate and foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	0	1	1	(1)
Other income, net	(2)	18	(5)	0
Equity earnings (losses)	0	1	1	5
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Foreign exchange instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Energy-related businesses	0	(1)	1	(1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of assets	10	0	10	0
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	(7)	(1)	(2)
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	7	8	6	0
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, net	2	3	4	6
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, net	22	0	22	0
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 (loss) from continuing operations before income taxes and equity earnings (losses)	24	3	27	6
Income tax (expense) benefit	(6)	(1)	(7)	(2)
Net income	18	2	20	4
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(102)	(53)	(205)	(105)
Other income, net	(19)	(25)	(41)	(53)
Income (loss) from continuing operations before income taxes and equity earnings (losses)	181	188	363	413
Income tax (expense) benefit	(35)	(42)	(40)	(98)
Net income	(146)	(146)	(323)	(315)
Earnings attributable to noncontrolling interest	(3)	0	(4)	1
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	1	0	1	0
San Diego Gas and Electric Company [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains (Losses) on Cash Flow hedges [Member] | Interest rate instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	1	1	2	4
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	(1)	(1)	(2)	(4)
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	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	0	1	0
Southern California Gas Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(34)	(26)	(68)	(53)
Other income, net	(1)	(13)	(17)	(46)
Income (loss) from continuing operations before income taxes and equity earnings (losses)	27	57	310	341
Income tax (expense) benefit	4	(23)	(15)	(82)
Net income	(31)	(34)	(295)	(259)
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	0	1
Southern California Gas Company [Member] | 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, net	$ 0	$ 1	$ 0	$ 1