GENERAL INFORMATION AND OTHER FINANCIAL DATA - VARIABLE INTEREST ENTITIES (Details) $ in Millions		3 Months Ended
	Mar. 09, 2018	Mar. 31, 2018 USD ($) MW	Mar. 31, 2017 USD ($)		Dec. 31, 2017 USD ($)
Variable Interest Entities [Line Items]
Equity method investment		$ 9,176			$ 0	[1]
Property, plant and equipment, net		37,025			36,503	[1]
Other noncontrolling interests		2,441			2,450	[1]
Energy-related businesses		364	$ 333	[2]
Operation and maintenance		(781)	(719)	[2]
Depreciation and amortization		(386)	(360)	[2],[3]
Interest expense		(216)	(169)	[2]
Income before income taxes		667	752	[2]
Income tax expense		(289)	(295)	[2]
(Losses) income before income taxes/Net (loss) income		358	452	[2],[3]
Losses (earnings) attributable to noncontrolling interest		17	(11)	[2]
Earnings attributable to common shares		347	441
Otay Mesa VIE [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net		316			321
Sempra Renewables [Member] | Tax Equity Investors [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net		1,412			1,412
Equity		607			631
Energy-related businesses		17	13
Operation and maintenance		(4)	(2)
Depreciation and amortization		(11)	(8)
Income before income taxes		2	3
Income tax expense		(5)	(2)
(Losses) income before income taxes/Net (loss) income		(3)	1
Losses (earnings) attributable to noncontrolling interest		21	3
Earnings attributable to common shares		18	4
Sempra Natural Gas [Member] | Cameron LNG Holdings [Member]
Variable Interest Entities [Line Items]
Equity method investment		1,085			997
Sempra Texas Utility [Member] | Oncor Holdings [Member]
Variable Interest Entities [Line Items]
Equity method investment		9,176
San Diego Gas and Electric Company [Member]
Variable Interest Entities [Line Items]
Property, plant and equipment, net		15,062			14,838	[1]
Other noncontrolling interests		30			28	[1]
Operation and maintenance		248	231	[2]
Depreciation and amortization		166	163	[2],[3]
Operating income		248	274	[2]
Interest expense		(52)	(49)	[2]
Income before income taxes		225	247	[2]
Income tax expense		(56)	(90)	[2]
(Losses) income before income taxes/Net (loss) income		169	157	[2],[3]
Losses (earnings) attributable to noncontrolling interest		$ 1	(2)	[2]
San Diego Gas and Electric Company [Member] | Otay Mesa VIE [Member]
Variable Interest Entities [Line Items]
Generating capacity (in mw) | MW		605
Conditional purchase obligation		$ 280
Equity of variable interest entity		30			28
Secured debt of variable interest entity		292
Property, plant and equipment, net		316			$ 321
Cost of electric fuel and purchased power		(16)	(18)
Operation and maintenance		4	4
Depreciation and amortization		8	7
Total operating expenses		(4)	(7)
Operating income		4	7
Interest expense		(5)	(5)
(Losses) income before income taxes/Net (loss) income		(1)	2
Losses (earnings) attributable to noncontrolling interest		1	(2)
Earnings attributable to common shares		$ 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%

[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 2016-18, which we discuss in Note 2.