NEW ACCOUNTING STANDARDS (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Other		$ 149		$ 62	[1]	$ 66	[1]
Changes in other assets		(214)		49	[1]	(169)	[1]
Net cash provided by operating activities		3,625		2,311	[1]	2,898	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisitions, net of cash, cash equivalents and restricted cash acquired		(270)		(1,504)	[1]	(198)	[1]
Other		(2)		9	[1]	9	[1]
Net cash used in investing activities		(4,700)		(4,835)	[1]	(2,868)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Other		(43)		(21)	[1]	(20)	[1]
Net Cash Provided by (Used in) Financing Activities		1,007		2,502	[1]	(176)	[1]
Effect of exchange rate changes on cash, cash equivalents and restricted cash		7		(3)	[1]	(14)	[1]
(Decrease) increase in cash, cash equivalents and restricted cash		(61)		(25)	[1]	(160)	[1]
Cash and cash equivalents, January 1	[2]	349
Cash and cash equivalents, December 31		288		349	[2]
Cash, cash equivalents and restricted cash, January 1	[1]	425		450		610
Cash, cash equivalents and restricted cash, December 31		364		425	[1]	450	[1]
Income Statement [Abstract]
Operation and maintenance		3,117		2,970		2,886
Other income, net		254		132		126
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Other				62		66
Changes in other assets				49		(169)
Net cash provided by operating activities				2,311		2,898
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisition of businesses, net of cash and cash equivalents acquired				0		0
Expenditures for investments and acquisitions, net of cash, cash equivalents and restricted cash acquired				(1,504)		(198)
Increases in restricted cash				0		0
Decreases in restricted cash				0		0
Other				9		9
Net cash used in investing activities				(4,835)		(2,868)
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(21)		(20)
Net Cash Provided by (Used in) Financing Activities				2,502		(176)
Effect of Exchange Rate on Cash and Cash Equivalents				0		0
Effect of exchange rate changes on cash, cash equivalents and restricted cash				(3)		(14)
(Decrease) increase in cash and cash equivalents				0		0
(Decrease) increase in cash, cash equivalents and restricted cash				(25)		(160)
Cash and cash equivalents, January 1		0		0		0
Cash and cash equivalents, December 31				0		0
Cash, cash equivalents and restricted cash, January 1		425		450		610
Cash, cash equivalents and restricted cash, December 31				425		450
As previously reported [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance		3,117		2,970
Other income, net		254		132
As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Other				63		66
Changes in other assets				56		(162)
Net cash provided by operating activities				2,319		2,905
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisition of businesses, net of cash and cash equivalents acquired				(1,582)		(200)
Expenditures for investments and acquisitions, net of cash, cash equivalents and restricted cash acquired				0		0
Increases in restricted cash				(139)		(100)
Decreases in restricted cash				175		93
Other				0		1
Net cash used in investing activities				(4,886)		(2,885)
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(10)		(17)
Net Cash Provided by (Used in) Financing Activities				2,513		(173)
Effect of Exchange Rate on Cash and Cash Equivalents				0		(14)
Effect of exchange rate changes on cash, cash equivalents and restricted cash				0		0
(Decrease) increase in cash and cash equivalents				(54)		(167)
(Decrease) increase in cash, cash equivalents and restricted cash				0		0
Cash and cash equivalents, January 1		349		403		570
Cash and cash equivalents, December 31				349		403
Cash, cash equivalents and restricted cash, January 1		0		0		0
Cash, cash equivalents and restricted cash, December 31				0		0
Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Other				(1)		0
Changes in other assets				(7)		(7)
Net cash provided by operating activities				(8)		(7)
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisition of businesses, net of cash and cash equivalents acquired				1,582		200
Expenditures for investments and acquisitions, net of cash, cash equivalents and restricted cash acquired				(1,504)		(198)
Increases in restricted cash				139		100
Decreases in restricted cash				(175)		(93)
Other				9		8
Net cash used in investing activities				51		17
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(11)		(3)
Net Cash Provided by (Used in) Financing Activities				(11)		(3)
Effect of Exchange Rate on Cash and Cash Equivalents				0		14
Effect of exchange rate changes on cash, cash equivalents and restricted cash				(3)		(14)
(Decrease) increase in cash and cash equivalents				54		167
(Decrease) increase in cash, cash equivalents and restricted cash				(25)		(160)
Cash and cash equivalents, January 1		(349)		(403)		(570)
Cash and cash equivalents, December 31				(349)		(403)
Cash, cash equivalents and restricted cash, January 1		425		450		610
Cash, cash equivalents and restricted cash, December 31				425		450
Recast [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance		3,096		2,976
Other income, net		233		138
San Diego Gas and Electric Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Other		(22)		(35)	[1]	(16)	[1]
Changes in other assets		(108)		(20)	[1]	(125)	[1]
Net cash provided by operating activities		1,547		1,323	[1]	1,661	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Other		9		6	[1]	5	[1]
Net cash used in investing activities		(1,515)		(1,324)	[1]	(1,077)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities		(23)		(22)	[1]	(568)	[1]
Cash and cash equivalents, January 1	[2]	8
Cash and cash equivalents, December 31		12		8	[2]
Cash, cash equivalents and restricted cash, January 1	[1]	20		43		27
Cash, cash equivalents and restricted cash, December 31		29		20	[1]	43	[1]
Income Statement [Abstract]
Utilities Operation and maintenance		1,020		1,048		1,017
Operating income		713		990		1,058
Other income, net		66		50		36
San Diego Gas and Electric Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other assets				(20)		(125)
Net cash provided by operating activities				1,323		1,661
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				0		0
Decreases in restricted cash				0		0
Other				6		5
Net cash used in investing activities				(1,324)		(1,077)
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(6)		(4)
Net Cash Provided by (Used in) Financing Activities				(22)		(568)
(Decrease) increase in cash and cash equivalents				0		0
(Decrease) increase in cash, cash equivalents and restricted cash				(23)		16
Cash and cash equivalents, January 1		0		0		0
Cash and cash equivalents, December 31				0		0
Cash, cash equivalents and restricted cash, January 1		20		43		27
Cash, cash equivalents and restricted cash, December 31				20		43
San Diego Gas and Electric Company [Member] | As previously reported [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Utilities Operation and maintenance		1,020		1,048
Operating income		713		990
Other income, net		66		50
San Diego Gas and Electric Company [Member] | As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other assets				(16)		(122)
Net cash provided by operating activities				1,327		1,664
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				(49)		(39)
Decreases in restricted cash				60		35
Other				0		0
Net cash used in investing activities				(1,319)		(1,086)
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(4)		(2)
Net Cash Provided by (Used in) Financing Activities				(20)		(566)
(Decrease) increase in cash and cash equivalents				(12)		12
(Decrease) increase in cash, cash equivalents and restricted cash				0		0
Cash and cash equivalents, January 1		8		20		8
Cash and cash equivalents, December 31				8		20
Cash, cash equivalents and restricted cash, January 1		0		0		0
Cash, cash equivalents and restricted cash, December 31				0		0
San Diego Gas and Electric Company [Member] | Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-15 and 2016-18 [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other assets				(4)		(3)
Net cash provided by operating activities				(4)		(3)
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				49		39
Decreases in restricted cash				(60)		(35)
Other				6		5
Net cash used in investing activities				(5)		9
CASH FLOWS FROM FINANCING ACTIVITIES
Other				(2)		(2)
Net Cash Provided by (Used in) Financing Activities				(2)		(2)
(Decrease) increase in cash and cash equivalents				12		(12)
(Decrease) increase in cash, cash equivalents and restricted cash				(23)		16
Cash and cash equivalents, January 1		(8)		(20)		(8)
Cash and cash equivalents, December 31				(8)		(20)
Cash, cash equivalents and restricted cash, January 1		20		43		27
Cash, cash equivalents and restricted cash, December 31				20		43
San Diego Gas and Electric Company [Member] | Recast [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Utilities Operation and maintenance		1,024		1,062
Operating income		709		976
Other income, net		70		64
Southern California Gas Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Other		11		(26)		(20)
Changes in other assets		(80)		35		(91)
Net cash provided by operating activities		1,306		671		880
CASH FLOWS FROM INVESTING ACTIVITIES
Other		4		0		0
Net cash used in investing activities		(1,363)		(1,269)		(1,402)
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities		53		552		495
(Decrease) increase in cash and cash equivalents		(4)		(46)		(27)
Cash and cash equivalents, January 1		12	[2]	58		85
Cash and cash equivalents, December 31		8		12	[2]	58
Income Statement [Abstract]
Utilities Operation and maintenance		1,479		1,385		1,361
Operating income		622		557		608
Other income, net		36		32		$ 30
Southern California Gas Company [Member] | As previously reported [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Utilities Operation and maintenance		1,479		1,385
Operating income		622		557
Other income, net		36		32
Southern California Gas Company [Member] | Recast [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Utilities Operation and maintenance		1,474		1,391
Operating income		627		551
Other income, net		$ 31		$ 38

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

[2] Reflects reclassifications to conform to current year presentation, which we discuss in Note 1.