NEW ACCOUNTING STANDARDS (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017		Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from change in accounting principle										$ (1)
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net					$ (177)	$ (72)	[1]
Net cash provided by operating activities					2,591	2,704	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisition of businesses, net of cash and cash equivalents acquired					(9,921)	(110)	[1]
Other					29	6	[1]
Net cash used in investing activities					(12,704)	(3,260)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Other					(80)	(11)	[1]
Net Cash Provided by (Used in) Financing Activities					10,045	381	[1]
Effect of exchange rate changes on cash, cash equivalents and restricted cash					(8)	11	[1]
(Decrease) increase in cash, cash equivalents and restricted cash					(76)	(164)	[1]
Cash and cash equivalents beginning balance	[2]				288
Cash and cash equivalents ending balance		$ 212			212
Cash, cash equivalents and restricted cash beginning balance					364	425	[1]
Cash, cash equivalents and restricted cash ending balance		288	$ 261	[1]	288	261	[1]
Income Statement [Abstract]
Operation and maintenance(1)		819	759	[3]	2,383	2,226	[3]
Other income, net		97	40	[3]	196	322	[3]
Statement of Financial Position [Abstract]
Retained earnings		9,485			9,485					10,147	[2]
Regulatory liabilities		3,974			3,974					3,922	[2]
Accumulated other comprehensive income (loss)		(612)			(612)					(626)	[2]
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						72
Net cash provided by operating activities						2,704
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						0
Decreases in restricted cash						0
Other						6
CASH FLOWS FROM FINANCING ACTIVITIES
Effect of Exchange Rate on Cash and Cash Equivalents						0
Effect of exchange rate changes on cash, cash equivalents and restricted cash						11
(Decrease) increase in cash and cash equivalents						0
(Decrease) increase in cash, cash equivalents and restricted cash						(164)
Cash and cash equivalents beginning balance						0
Cash and cash equivalents ending balance			0			0
Cash, cash equivalents and restricted cash beginning balance						425
Cash, cash equivalents and restricted cash ending balance			261			261
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-01 and 2018-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from change in accounting principle									$ 1
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance(1)			759			2,226
Other income, net			40			322
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-12 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment from change in accounting principle									$ 3
As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						(66)
Net cash provided by operating activities						2,710
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						(293)
Decreases in restricted cash						298
Other						1
CASH FLOWS FROM FINANCING ACTIVITIES
Effect of Exchange Rate on Cash and Cash Equivalents						9
Effect of exchange rate changes on cash, cash equivalents and restricted cash						0
(Decrease) increase in cash and cash equivalents						(160)
(Decrease) increase in cash, cash equivalents and restricted cash						0
Cash and cash equivalents beginning balance						349
Cash and cash equivalents ending balance			189			189
Cash, cash equivalents and restricted cash beginning balance						0
Cash, cash equivalents and restricted cash ending balance			0			0
As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance(1)			760			2,205
Other income, net			41			301
Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						(6)
Net cash provided by operating activities						(6)
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						293
Decreases in restricted cash						(298)
Other						5
CASH FLOWS FROM FINANCING ACTIVITIES
Effect of Exchange Rate on Cash and Cash Equivalents						(9)
Effect of exchange rate changes on cash, cash equivalents and restricted cash						11
(Decrease) increase in cash and cash equivalents						160
(Decrease) increase in cash, cash equivalents and restricted cash						(164)
Cash and cash equivalents beginning balance						(349)
Cash and cash equivalents ending balance			(189)			(189)
Cash, cash equivalents and restricted cash beginning balance						425
Cash, cash equivalents and restricted cash ending balance			261			261
Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance(1)			(1)			21
Other income, net			(1)			21
San Diego Gas and Electric Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net					(16)	(10)	[1]
Net cash provided by operating activities					1,231	1,172	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Other					0	6	[1]
Net cash used in investing activities					(1,194)	(1,085)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities					(22)	(74)	[1]
Cash and cash equivalents beginning balance	[2]				12
Cash and cash equivalents ending balance		27			27
Cash, cash equivalents and restricted cash beginning balance					29	20	[1]
Cash, cash equivalents and restricted cash ending balance		44	33	[1]	44	33	[1]
Income Statement [Abstract]
Operation and maintenance		262	253	[3]	761	725	[3]
Total operating expenses		999	1,294	[3]	2,642	2,898	[3]
Operating income		300	(58)	[3]	763	453	[3]
Other income, net		24	20	[3]	77	61	[3]
Statement of Financial Position [Abstract]
Retained earnings		4,539			4,539					4,268	[2]
Regulatory liabilities		2,319			2,319					2,225	[2]
Accumulated other comprehensive income (loss)		(14)			(14)					(8)	[2]
San Diego Gas and Electric Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						(10)
Net cash provided by operating activities						1,172
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						0
Decreases in restricted cash						0
Other						6
Net cash used in investing activities						(1,085)
CASH FLOWS FROM FINANCING ACTIVITIES
(Decrease) increase in cash and cash equivalents						0
(Decrease) increase in cash, cash equivalents and restricted cash						13
Cash and cash equivalents beginning balance						0
Cash and cash equivalents ending balance			0			0
Cash, cash equivalents and restricted cash beginning balance						20
Cash, cash equivalents and restricted cash ending balance			33			33
San Diego Gas and Electric Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			253			725
Total operating expenses			1,294			2,898
Operating income			(58)			453
Other income, net			20			61
San Diego Gas and Electric Company [Member] | As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						(4)
Net cash provided by operating activities						1,178
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						(21)
Decreases in restricted cash						18
Other						0
Net cash used in investing activities						(1,094)
CASH FLOWS FROM FINANCING ACTIVITIES
(Decrease) increase in cash and cash equivalents						10
(Decrease) increase in cash, cash equivalents and restricted cash						0
Cash and cash equivalents beginning balance						8
Cash and cash equivalents ending balance			18			18
Cash, cash equivalents and restricted cash beginning balance						0
Cash, cash equivalents and restricted cash ending balance			0			0
San Diego Gas and Electric Company [Member] | As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			249			713
Total operating expenses			1,290			2,886
Operating income			(54)			465
Other income, net			16			49
San Diego Gas and Electric Company [Member] | Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Updates 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net						(6)
Net cash provided by operating activities						(6)
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash						21
Decreases in restricted cash						(18)
Other						6
Net cash used in investing activities						9
CASH FLOWS FROM FINANCING ACTIVITIES
(Decrease) increase in cash and cash equivalents						(10)
(Decrease) increase in cash, cash equivalents and restricted cash						13
Cash and cash equivalents beginning balance						(8)
Cash and cash equivalents ending balance			(18)			(18)
Cash, cash equivalents and restricted cash beginning balance						20
Cash, cash equivalents and restricted cash ending balance			33			33
San Diego Gas and Electric Company [Member] | Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			4			12
Total operating expenses			4			12
Operating income			(4)			(12)
Other income, net			4			12
Southern California Gas Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other noncurrent assets and liabilities, net					(178)	(74)	[1]
Net cash provided by operating activities					882	1,066	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Other					6	0	[1]
Net cash used in investing activities					(1,209)	(1,033)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities					323	(37)	[1]
(Decrease) increase in cash and cash equivalents					(4)	(4)	[1]
Cash and cash equivalents beginning balance	[2]				8
Cash and cash equivalents ending balance		4			4
Cash, cash equivalents and restricted cash beginning balance					8	12	[1]
Cash, cash equivalents and restricted cash ending balance		4	8	[1]	4	8	[1]
Income Statement [Abstract]
Operation and maintenance		394	360	[3]	1,160	1,067	[3]
Total operating expenses		797	679	[3]	2,348	2,298	[3]
Operating income		5	5	[3]	352	397	[3]
Other income, net		3	13	[3]	49	51	[3]
Statement of Financial Position [Abstract]
Retained earnings		3,234			3,234					3,040	[2]
Regulatory liabilities		1,655			1,655					1,697	[2]
Accumulated other comprehensive income (loss)		$ (20)			$ (20)					$ (21)	[2]
Southern California Gas Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			360			1,067
Total operating expenses			679			2,298
Operating income			5			397
Other income, net			13			51
Southern California Gas Company [Member] | As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			355			1,044
Total operating expenses			674			2,275
Operating income			10			420
Other income, net			8			28
Southern California Gas Company [Member] | Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance			5			23
Total operating expenses			5			23
Operating income			(5)			(23)
Other income, net			$ 5			$ 23
Forecast [Member] | Accounting Standards Update 2018-02 [Member]
Statement of Financial Position [Abstract]
Retained earnings								$ 42
Regulatory liabilities								2
Accumulated other comprehensive income (loss)								44
Forecast [Member] | San Diego Gas and Electric Company [Member] | Accounting Standards Update 2018-02 [Member]
Statement of Financial Position [Abstract]
Retained earnings								2
Forecast [Member] | Southern California Gas Company [Member] | Accounting Standards Update 2018-02 [Member]
Statement of Financial Position [Abstract]
Retained earnings								2
Regulatory liabilities								2
Accumulated other comprehensive income (loss)								$ 4

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

[2] Derived from audited financial statements.

[3] 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.