GENERAL INFORMATION AND OTHER FINANCIAL DATA - CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	[1]	$ 23,373
OCI before reclassifications		75	$ (276)
Amounts reclassified from AOCI		26	25
Net OCI		101	(251)
Ending balance		23,999
Foreign currency translation adjustments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(64)	(607)
OCI before reclassifications		(5)	(138)
Amounts reclassified from AOCI		0	0
Net OCI		(5)	(138)
Ending balance		(69)	(745)
Financial instruments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(331)	(215)
OCI before reclassifications		73	(154)
Amounts reclassified from AOCI		19	19
Net OCI		92	(135)
Ending balance		(239)	(350)
Pension and other postretirement benefits [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(105)	(117)
OCI before reclassifications		7	16
Amounts reclassified from AOCI		7	6
Net OCI		14	22
Ending balance		(91)	(95)
Total accumulated other comprehensive income (loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(500)	(939)
Ending balance		(399)	(1,190)
San Diego Gas and Electric Company [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	[1]	7,730
Ending balance		7,942
San Diego Gas and Electric Company [Member] | Pension and other postretirement benefits [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(10)	(16)
Ending balance		(10)	(16)
San Diego Gas and Electric Company [Member] | Total accumulated other comprehensive income (loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(10)	(16)
Ending balance		(10)	(16)
Southern California Gas Company [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	[1]	5,144
Ending balance		5,501
Southern California Gas Company [Member] | Financial instruments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(13)	(13)
Ending balance		(13)	(13)
Southern California Gas Company [Member] | Pension and other postretirement benefits [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(18)	(10)
Ending balance		(18)	(10)
Southern California Gas Company [Member] | Total accumulated other comprehensive income (loss) [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(31)	(23)
Ending balance		$ (31)	$ (23)

[1] Derived from audited financial statements.