NEW ACCOUNTING STANDARDS (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017		Jan. 01, 2018
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 assets		$ (107)		$ (41)	[1]
Net cash provided by operating activities		966		1,004	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for investments and acquisition of businesses, net of cash and cash equivalents acquired		(9,617)		(59)	[1]
Other		26		4	[1]
Net cash used in investing activities		(10,632)		(1,026)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Other		(52)		(5)	[1]
Net Cash Provided by (Used in) Financing Activities		9,608		(46)	[1]
Effect of exchange rate changes on cash, cash equivalents and restricted cash		1		10	[1]
(Decrease) increase in cash, cash equivalents and restricted cash		(57)		(58)	[1]
Cash and cash equivalents beginning balance	[2]	288
Cash and cash equivalents ending balance		239
Cash, cash equivalents and restricted cash beginning balance		364		425	[1]
Cash, cash equivalents and restricted cash ending balance		307		367	[1]
Income Statement [Abstract]
Operation and maintenance		781		719	[3]
Other income, net		153		174	[3]
New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				0
Decreases in restricted cash				0
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				10
(Decrease) increase in cash and cash equivalents				0
(Decrease) increase in cash, cash equivalents and restricted cash				(58)
Cash and cash equivalents beginning balance				0
Cash and cash equivalents ending balance				0
Cash, cash equivalents and restricted cash beginning balance				425
Cash, cash equivalents and restricted cash ending balance				367
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				719
Other income, net				174
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 Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				(93)
Decreases in restricted cash				93
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				(59)
(Decrease) increase in cash, cash equivalents and restricted cash				0
Cash and cash equivalents beginning balance				349
Cash and cash equivalents ending balance				290
Cash, cash equivalents and restricted cash beginning balance				0
Cash, cash equivalents and restricted cash ending balance				0
As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance				714
Other income, net				169
Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				93
Decreases in restricted cash				(93)
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				10
(Decrease) increase in cash and cash equivalents				59
(Decrease) increase in cash, cash equivalents and restricted cash				(58)
Cash and cash equivalents beginning balance				(349)
Cash and cash equivalents ending balance				(290)
Cash, cash equivalents and restricted cash beginning balance				425
Cash, cash equivalents and restricted cash ending balance				367
Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance				5
Other income, net				5
San Diego Gas and Electric Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other assets		(33)		(34)	[1]
Net cash provided by operating activities		404		386	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Net cash used in investing activities		(475)		(380)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities		67		5	[1]
Cash and cash equivalents beginning balance	[2]	12
Cash and cash equivalents ending balance		9
Cash, cash equivalents and restricted cash beginning balance		29		20	[1]
Cash, cash equivalents and restricted cash ending balance		25		31	[1]
Income Statement [Abstract]
Operation and maintenance		248		231	[3]
Total operating expenses		807		783	[3]
Operating income		248		274	[3]
Other income, net		28		22	[3]
San Diego Gas and Electric Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				0
Decreases in restricted cash				0
Net cash used in investing activities				(380)
CASH FLOWS FROM FINANCING ACTIVITIES
(Decrease) increase in cash and cash equivalents				0
(Decrease) increase in cash, cash equivalents and restricted cash				11
Cash and cash equivalents beginning balance				0
Cash and cash equivalents ending balance				0
Cash, cash equivalents and restricted cash beginning balance				20
Cash, cash equivalents and restricted cash ending balance				31
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				231
Total operating expenses				783
Operating income				274
Other income, net				22
San Diego Gas and Electric Company [Member] | As previously reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				(10)
Decreases in restricted cash				9
Net cash used in investing activities				(381)
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
Cash, cash equivalents and restricted cash beginning balance				0
Cash, cash equivalents and restricted cash ending balance				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				227
Total operating expenses				779
Operating income				278
Other income, net				18
San Diego Gas and Electric Company [Member] | Effect of adoption [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2016-18 [Member]
CASH FLOWS FROM INVESTING ACTIVITIES
Increases in restricted cash				10
Decreases in restricted cash				(9)
Net cash used in investing activities				1
CASH FLOWS FROM FINANCING ACTIVITIES
(Decrease) increase in cash and cash equivalents				(10)
(Decrease) increase in cash, cash equivalents and restricted cash				11
Cash and cash equivalents beginning balance				(8)
Cash and cash equivalents ending balance				(18)
Cash, cash equivalents and restricted cash beginning balance				20
Cash, cash equivalents and restricted cash ending balance				31
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
Total operating expenses				4
Operating income				(4)
Other income, net				4
Southern California Gas Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Changes in other assets		(57)		(21)	[1]
Net cash provided by operating activities		419		463	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Other		3		0	[1]
Net cash used in investing activities		(400)		(392)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Net Cash Provided by (Used in) Financing Activities		(16)		(62)	[1]
(Decrease) increase in cash and cash equivalents		3		9	[1]
Cash and cash equivalents beginning balance		8	[2]	12	[1]
Cash and cash equivalents ending balance		11		21	[1]
Income Statement [Abstract]
Operation and maintenance		384		356	[3]
Total operating expenses		848		929	[3]
Operating income		278		312	[3]
Other income, net		$ 33		14	[3]
Southern California Gas Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member] | Accounting Standards Update 2017-07 [Member]
Income Statement [Abstract]
Operation and maintenance				356
Total operating expenses				929
Operating income				312
Other income, net				14
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				353
Total operating expenses				926
Operating income				315
Other income, net				11
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				3
Total operating expenses				3
Operating income				(3)
Other income, net				$ 3

[1] As adjusted for the retrospective adoption of 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.