NEW ACCOUNTING STANDARDS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016		Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment								$ 107
Weighted-average number of shares outstanding, diluted	252,822,000	252,036,000	[1]	252,609,000	251,775,000	[1]
Income Statement [Abstract]
Income tax (expense) benefit	$ (167)	$ 106	[1]	$ (462)	$ (2)	[1]
Net Income	248	27	[1]	700	391	[1],[2]
Earnings	$ 259	$ 16	[1]	$ 700	$ 369	[1]
Basic earnings per common share (in dollars per share)	$ 1.03	$ 0.06	[1]	$ 2.79	$ 1.48	[1]
Diluted earnings per common share (in dollars per share)	$ 1.03	$ 0.06	[1]	$ 2.77	$ 1.47	[1]
Increase in weighted-average common shares outstanding for diluted EPS (in shares)	252,822,000	252,036,000	[1]	252,609,000	251,775,000	[1]
Statement of Comprehensive Income [Abstract]
Comprehensive income				$ 739	$ 346
Cash flows from operating activities:
Deferred income taxes and investment tax credits				411	(76)	[2]
Other				(19)	45	[2]
Net cash provided by operating activities				1,889	916	[2]
CASH FLOWS FROM INVESTING ACTIVITIES
Net cash used in investing activities				(2,067)	(1,593)	[2]
Cash flows from financing activities:
Net cash provided by financing activities				44	$ 882	[2]
Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Weighted-average number of shares outstanding, diluted	252,036				251,775,000
Income Statement [Abstract]
Income tax (expense) benefit					$ (2)
Net Income					391
Earnings					$ 369
Basic earnings per common share (in dollars per share)					$ 1.48
Diluted earnings per common share (in dollars per share)					$ 1.47
Increase in weighted-average common shares outstanding for diluted EPS (in shares)	252,036				251,775,000
Statement of Comprehensive Income [Abstract]
Comprehensive income					$ 346
Comprehensive income (loss) after preferred dividends of subsidiary					345
Cash flows from operating activities:
Deferred income taxes and investment tax credits					(76)
Other					45
Net cash provided by operating activities					916
Cash flows from financing activities:
Tax benefit related to share-based compensation					0
Net cash provided by financing activities					882
Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-18 [Member]
Statement of Cash Flows [Abstract]
Cash, cash equivalents and restricted cash, beginning of period	$ 87			87			$ 76
As previously reported [Member]
Cash flows from operating activities:
Other					$ 33
As previously reported [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Weighted-average number of shares outstanding, diluted	251,938				251,686,000
Income Statement [Abstract]
Income tax (expense) benefit					$ (36)
Net Income					357
Earnings					$ 335
Basic earnings per common share (in dollars per share)					$ 1.34
Diluted earnings per common share (in dollars per share)					$ 1.33
Increase in weighted-average common shares outstanding for diluted EPS (in shares)	251,938				251,686,000
Statement of Comprehensive Income [Abstract]
Comprehensive income					$ 312
Comprehensive income (loss) after preferred dividends of subsidiary					311
Cash flows from operating activities:
Deferred income taxes and investment tax credits					(42)
Other					11
Net cash provided by operating activities					882
Cash flows from financing activities:
Tax benefit related to share-based compensation					34
Net cash provided by financing activities					916
Effect of adoption [Member]
Cash flows from operating activities:
Other					$ 22
Effect of adoption [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Weighted-average number of shares outstanding, diluted					89,000
Income Statement [Abstract]
Income tax (expense) benefit					$ 34
Net Income					34
Earnings					$ 34
Basic earnings per common share (in dollars per share)					$ 0.14
Diluted earnings per common share (in dollars per share)					$ 0.14
Increase in weighted-average common shares outstanding for diluted EPS (in shares)					89,000
Statement of Comprehensive Income [Abstract]
Comprehensive income					$ 34
Comprehensive income (loss) after preferred dividends of subsidiary					34
Cash flows from operating activities:
Deferred income taxes and investment tax credits					(34)
Other					34
Net cash provided by operating activities					34
Cash flows from financing activities:
Tax benefit related to share-based compensation					(34)
Net cash provided by financing activities					(34)
San Diego Gas and Electric Company [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment								23
Income Statement [Abstract]
Income tax (expense) benefit	$ (54)	$ (48)		(144)	(113)	[1]
Net Income	153	87		310	224	[1]
Earnings attributable to common shares	149	100		304	236	[1]
Statement of Comprehensive Income [Abstract]
Comprehensive income				314	223
Cash flows from operating activities:
Deferred income taxes and investment tax credits				98	19	[2]
Other				(20)	(21)	[2]
Net cash provided by operating activities				690	508	[2]
CASH FLOWS FROM INVESTING ACTIVITIES
Net cash used in investing activities				(734)	(770)	[2]
Cash flows from financing activities:
Net cash provided by financing activities				48	250	[2]
San Diego Gas and Electric Company [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					(113)
Net Income					224
Earnings attributable to common shares					236
Statement of Comprehensive Income [Abstract]
Comprehensive income					223
Cash flows from operating activities:
Deferred income taxes and investment tax credits					19
San Diego Gas and Electric Company [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-18 [Member]
Statement of Cash Flows [Abstract]
Cash, cash equivalents and restricted cash, beginning of period	14			14			$ 12
San Diego Gas and Electric Company [Member] | As previously reported [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					(120)
Net Income					217
Earnings attributable to common shares					229
Statement of Comprehensive Income [Abstract]
Comprehensive income					216
Cash flows from operating activities:
Deferred income taxes and investment tax credits					26
San Diego Gas and Electric Company [Member] | Effect of adoption [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					7
Net Income					7
Earnings attributable to common shares					7
Statement of Comprehensive Income [Abstract]
Comprehensive income					7
Cash flows from operating activities:
Deferred income taxes and investment tax credits					(7)
Southern California Gas Company [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative-effect adjustment								$ 15
Income Statement [Abstract]
Income tax (expense) benefit	(19)	29		(117)	(54)	[1]
Net Income	59	0		262	199	[2]
Earnings attributable to common shares	$ 58	$ (1)		261	198	[1],[2]
Statement of Comprehensive Income [Abstract]
Comprehensive income				263	199
Cash flows from operating activities:
Deferred income taxes and investment tax credits				96	28	[2]
Other				(13)	(15)	[2]
Net cash provided by operating activities				855	262	[2]
CASH FLOWS FROM INVESTING ACTIVITIES
Net cash used in investing activities				(766)	(600)	[2]
Cash flows from financing activities:
Net cash provided by financing activities				$ (63)	491	[2]
Southern California Gas Company [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					(54)
Net Income					199
Earnings attributable to common shares					198
Cash flows from operating activities:
Deferred income taxes and investment tax credits					28
Southern California Gas Company [Member] | As previously reported [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					(58)
Net Income					195
Earnings attributable to common shares					194
Cash flows from operating activities:
Deferred income taxes and investment tax credits					32
Southern California Gas Company [Member] | Effect of adoption [Member] | Effect of Early Adoption of New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income Statement [Abstract]
Income tax (expense) benefit					4
Net Income					4
Earnings attributable to common shares					4
Cash flows from operating activities:
Deferred income taxes and investment tax credits					$ (4)

[1] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.

[2] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.