GENERAL INFORMATION AND OTHER FINANCIAL DATA - RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (280)	$ (260)
Other (Expense) Income, Net	254	(82)
Equity earnings	263	101
Energy-related businesses	364	383
Income from continuing operations before income taxes and equity earnings	397	501
Income tax benefit (expense)	207	(42)
Net income	947	518
Earnings attributable to noncontrolling interest	(151)	(41)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings attributable to common shares	25	1
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 from continuing operations before income taxes and equity earnings	39	0
Income tax benefit (expense)	(12)	0
Net income	27	0
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	2	1
Other (Expense) Income, Net	41	(3)
Equity earnings	0	1
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]
Other (Expense) Income, Net	(2)	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	(8)	(1)
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	19	(1)
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 (Expense) Income, Net	2	2
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 (Expense) Income, 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 (Expense) Income, Net	5	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 from continuing operations before income taxes and equity earnings	8	3
Income tax benefit (expense)	(2)	(1)
Net income	6	2
San Diego Gas and Electric Company [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(101)	(103)
Other (Expense) Income, Net	(31)	(22)
Income from continuing operations before income taxes and equity earnings	320	182
Income tax benefit (expense)	(58)	(5)
Net income	262	177
Earnings attributable to noncontrolling interest	0	(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	0	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	0	1
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)