GENERAL INFORMATION AND OTHER FINANCIAL DATA - VARIABLE INTEREST ENTITIES (Details)		3 Months Ended			9 Months Ended
	Mar. 09, 2018	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)		Sep. 30, 2018 USD ($) MW	Sep. 30, 2017 USD ($)		Dec. 31, 2017 USD ($)
Variable Interest Entities [Line Items]
Equity method investment		$ 9,553,000,000			$ 9,553,000,000			$ 0	[1]
Property, plant and equipment, net		35,498,000,000			35,498,000,000			36,503,000,000	[1]
Other noncontrolling interests		2,474,000,000			2,474,000,000			2,450,000,000	[1]
Energy-related businesses		480,000,000	$ 402,000,000	[2]	1,218,000,000	$ 1,071,000,000	[2]
Operation and maintenance		(819,000,000)	(759,000,000)	[2]	(2,383,000,000)	(2,226,000,000)	[2]
Depreciation and amortization		(380,000,000)	(378,000,000)	[2]	(1,158,000,000)	(1,106,000,000)	[2],[3]
Interest expense		(232,000,000)	(165,000,000)	[2]	(685,000,000)	(493,000,000)	[2]
Income before income taxes		427,000,000	5,000,000	[2]	(15,000,000)	1,154,000,000	[2]
Income tax expense		(167,000,000)	84,000,000	[2]	127,000,000	(378,000,000)	[2]
Net income		334,000,000	102,000,000	[2]	162,000,000	802,000,000	[2],[3]
(Earnings) losses attributable to noncontrolling interest		(24,000,000)	(45,000,000)	[2]	(12,000,000)	(44,000,000)	[2]
Otay Mesa VIE [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net		302,000,000			302,000,000			321,000,000
Sempra Renewables [Member] | Tax Equity Investors [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net								1,412,000,000
Equity		656,000,000			656,000,000			631,000,000
Energy-related businesses		28,000,000	17,000,000		77,000,000	48,000,000
Operation and maintenance		(5,000,000)	(5,000,000)		(13,000,000)	(14,000,000)
Depreciation and amortization		(13,000,000)	(8,000,000)		(36,000,000)	(24,000,000)
Income before income taxes		10,000,000	4,000,000		28,000,000	10,000,000
Income tax expense		(4,000,000)	(3,000,000)		(16,000,000)	(9,000,000)
Net income		6,000,000	1,000,000		12,000,000	1,000,000
(Earnings) losses attributable to noncontrolling interest		9,000,000	6,000,000		50,000,000	16,000,000
Earnings attributable to common shares		15,000,000	7,000,000		62,000,000	17,000,000
Sempra Natural Gas [Member] | Cameron LNG Holdings [Member]
Variable Interest Entities [Line Items]
Equity method investment		1,252,000,000			1,252,000,000			997,000,000
Sempra Texas Utility [Member] | Oncor Holdings [Member]
Variable Interest Entities [Line Items]
Equity method investment		9,553,000,000			9,553,000,000
Commitment to invest		1,025,000,000			1,025,000,000
Management Agreement Termination Fee					40,000,000
San Diego Gas and Electric Company [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net		15,524,000,000			15,524,000,000			14,838,000,000	[1]
Other noncontrolling interests		37,000,000			37,000,000			28,000,000	[1]
Operation and maintenance		262,000,000	253,000,000	[2]	761,000,000	725,000,000	[2]
Depreciation and amortization		174,000,000	170,000,000	[3]	509,000,000	499,000,000	[2]
Operating income		300,000,000	(58,000,000)	[2]	763,000,000	453,000,000	[2]
Interest expense		(56,000,000)	(53,000,000)	[2]	(161,000,000)	(151,000,000)	[2]
Income before income taxes		269,000,000	(91,000,000)	[2]	682,000,000	363,000,000	[2]
Income tax expense		(53,000,000)	72,000,000	[2]	(151,000,000)	(72,000,000)	[2]
Net income		216,000,000	(19,000,000)	[2]	531,000,000	291,000,000	[2],[3]
(Earnings) losses attributable to noncontrolling interest		(11,000,000)	(9,000,000)	[2]	$ (10,000,000)	(15,000,000)	[2]
San Diego Gas and Electric Company [Member] | Otay Mesa VIE [Member]
Variable Interest Entities [Line Items]
Generating capacity | MW					605
Conditional purchase obligation		280,000,000			$ 280,000,000
Equity of variable interest entity		37,000,000			37,000,000			28,000,000
Secured debt of variable interest entity		287,000,000			287,000,000
Property, plant and equipment, net		302,000,000			302,000,000			$ 321,000,000
Cost of electric fuel and purchased power		(28,000,000)	(26,000,000)		(60,000,000)	(65,000,000)
Operation and maintenance		3,000,000	4,000,000		11,000,000	13,000,000
Depreciation and amortization		8,000,000	7,000,000		23,000,000	21,000,000
Total operating expenses		(17,000,000)	(15,000,000)		(26,000,000)	(31,000,000)
Operating income		17,000,000	15,000,000		26,000,000	31,000,000
Interest expense		(6,000,000)	(6,000,000)		(16,000,000)	(16,000,000)
Net income		11,000,000	9,000,000		10,000,000	15,000,000
(Earnings) losses attributable to noncontrolling interest		(11,000,000)	(9,000,000)		(10,000,000)	(15,000,000)
Earnings attributable to common shares		$ 0	$ 0		0	$ 0
Oncor Holdings [Member] | Sempra Texas Holdings Corp [Member] | Sempra Texas Intermediate Holding Company LLC [Member]
Variable Interest Entities [Line Items]
Ownership percentage in consolidated entity	100.00%
Oncor Electric Delivery Company LLC. [Member]
Variable Interest Entities [Line Items]
Acquired percentage interest	80.25%
Oncor Electric Delivery Company LLC. [Member] | Sempra Texas Holdings Corp [Member]
Variable Interest Entities [Line Items]
Acquired percentage interest	80.03%
Property, Plant and Equipment, Net [Member] | Sempra Renewables [Member] | Tax Equity Investors [Member]
Variable Interest Entities [Line Items]
Assets reclassified to held-for-sale					$ 1,414,000,000

[1] Derived from audited financial statements.

[2] As adjusted for the retrospective adoption of ASU 2017-07, which we discuss in Note 2, and a reclassification to conform to current year presentation, which we discuss in Note 1.

[3] As adjusted for the retrospective adoption of ASU 2016-15 and ASU 2016-18, which we discuss in Note 2.