OTHER FINANCIAL DATA - CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	$ (718,000,000)	$ (852,000,000)	$ (748,000,000)	[1]	$ (806,000,000)
OCI before reclassifications	35,000,000	(20,000,000)	56,000,000		(71,000,000)
Amounts reclassified from accumulated other comprehensive income	5,000,000	7,000,000	14,000,000		12,000,000
Net OCI	40,000,000	(13,000,000)	70,000,000		(59,000,000)
AOCI, ending balance	(678,000,000)	(865,000,000)	(678,000,000)		(865,000,000)
Foreign currency translation adjustments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(478,000,000)	(503,000,000)	(527,000,000)		(582,000,000)
OCI before reclassifications	27,000,000	(28,000,000)	76,000,000		51,000,000
Amounts reclassified from accumulated other comprehensive income	0	0	0		0
Net OCI	27,000,000	(28,000,000)	76,000,000		51,000,000
AOCI, ending balance	(451,000,000)	(531,000,000)	(451,000,000)		(531,000,000)
Financial instruments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(147,000,000)	(264,000,000)	(125,000,000)		(137,000,000)
OCI before reclassifications	8,000,000	8,000,000	(20,000,000)		(122,000,000)
Amounts reclassified from accumulated other comprehensive income	(2,000,000)	5,000,000	4,000,000		8,000,000
Net OCI	6,000,000	13,000,000	(16,000,000)		(114,000,000)
AOCI, ending balance	(141,000,000)	(251,000,000)	(141,000,000)		(251,000,000)
Pension and other postretirement benefits [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(93,000,000)	(85,000,000)	(96,000,000)		(87,000,000)
OCI before reclassifications	0	0	0		0
Amounts reclassified from accumulated other comprehensive income	7,000,000	2,000,000	10,000,000		4,000,000
Net OCI	7,000,000	2,000,000	10,000,000		4,000,000
AOCI, ending balance	(86,000,000)	(83,000,000)	(86,000,000)		(83,000,000)
San Diego Gas and Electric Company [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(8,000,000)	(8,000,000)	(8,000,000)	[1]	(8,000,000)
Amounts reclassified from accumulated other comprehensive income	1,000,000	0	1,000,000		0
Net OCI	1,000,000		1,000,000
AOCI, ending balance	(7,000,000)	(8,000,000)	(7,000,000)		(8,000,000)
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]
AOCI, beginning balance	(8,000,000)	(8,000,000)	(8,000,000)		(8,000,000)
Amounts reclassified from accumulated other comprehensive income	1,000,000		1,000,000
Net OCI	1,000,000		1,000,000
AOCI, ending balance	(7,000,000)	(8,000,000)	(7,000,000)		(8,000,000)
Southern California Gas Company [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(21,000,000)	(19,000,000)	(22,000,000)	[1]	(19,000,000)
Amounts reclassified from accumulated other comprehensive income	0	1,000,000	1,000,000		1,000,000
Net OCI		1,000,000	1,000,000		1,000,000
AOCI, ending balance	(21,000,000)	(18,000,000)	(21,000,000)		(18,000,000)
Southern California Gas Company [Member] | Financial instruments [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(13,000,000)	(14,000,000)	(13,000,000)		(14,000,000)
Amounts reclassified from accumulated other comprehensive income		1,000,000	0		1,000,000
Net OCI		1,000,000	0		1,000,000
AOCI, ending balance	(13,000,000)	(13,000,000)	(13,000,000)		(13,000,000)
Southern California Gas Company [Member] | Pension and other postretirement benefits [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI, beginning balance	(8,000,000)	(5,000,000)	(9,000,000)		(5,000,000)
Amounts reclassified from accumulated other comprehensive income		0	1,000,000		0
Net OCI		0	1,000,000		0
AOCI, ending balance	$ (8,000,000)	$ (5,000,000)	$ (8,000,000)		$ (5,000,000)

[1] Derived from audited financial statements.