NEW ACCOUNTING STANDARDS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 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		252,246	251,487	[1]
Income Statement [Abstract]
Income tax expense		$ (295)	$ (108)	[1]
Net Income		452	364	[1],[2]
Earnings		$ 441	$ 353	[1]
Basic earnings per common share (in dollars per share)		$ 1.76	$ 1.41	[1]
Diluted earnings per common share (in dollars per share)		$ 1.75	$ 1.40	[1]
Increase in weighted-average common shares outstanding for diluted EPS (in shares)		252,246	251,487	[1]
Statement of Comprehensive Income [Abstract]
Comprehensive income		$ 515	$ 349
Cash flows from operating activities:
Deferred income taxes and investment tax credits		268	78	[2]
Other		(22)	36	[2]
Net cash provided by operating activities		1,004	626	[2]
Cash flows from financing activities:
Net cash provided by financing activities		(46)	$ 330	[2]
Restricted cash		77			$ 76
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			251,487
Income Statement [Abstract]
Income tax expense			$ (108)
Net Income			364
Earnings			$ 353
Basic earnings per common share (in dollars per share)			$ 1.41
Diluted earnings per common share (in dollars per share)			$ 1.40
Increase in weighted-average common shares outstanding for diluted EPS (in shares)			251,487
Statement of Comprehensive Income [Abstract]
Comprehensive income			$ 349
Cash flows from operating activities:
Deferred income taxes and investment tax credits			78
Other			36
Net cash provided by operating activities			626
Cash flows from financing activities:
Tax benefit related to share-based compensation			0
Net cash provided by financing activities			$ 330
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			251,412
Income Statement [Abstract]
Income tax expense			$ (142)
Net Income			330
Earnings			$ 319
Basic earnings per common share (in dollars per share)			$ 1.28
Diluted earnings per common share (in dollars per share)			$ 1.27
Increase in weighted-average common shares outstanding for diluted EPS (in shares)			251,412
Statement of Comprehensive Income [Abstract]
Comprehensive income			$ 315
Cash flows from operating activities:
Deferred income taxes and investment tax credits			112
Other			2
Net cash provided by operating activities			592
Cash flows from financing activities:
Tax benefit related to share-based compensation			34
Net cash provided by financing activities			$ 364
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			75
Income Statement [Abstract]
Income tax expense			$ 34
Net Income			34
Earnings			$ 34
Basic earnings per common share (in dollars per share)			$ 0.13
Diluted earnings per common share (in dollars per share)			$ 0.13
Increase in weighted-average common shares outstanding for diluted EPS (in shares)			75
Statement of Comprehensive Income [Abstract]
Comprehensive income			$ 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		(90)	(65)	[1]
Net Income		157	137	[1],[2]
Earnings attributable to common shares		155	136	[1]
Statement of Comprehensive Income [Abstract]
Comprehensive income		160	135
Cash flows from operating activities:
Deferred income taxes and investment tax credits		34	13	[2]
Other		(12)	(9)	[2]
Net cash provided by operating activities		386	369	[2]
Cash flows from financing activities:
Net cash provided by financing activities		5	(23)	[2]
Restricted cash		13			$ 12
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			(65)
Net Income			137
Earnings attributable to common shares			136
Statement of Comprehensive Income [Abstract]
Comprehensive income			135
Cash flows from operating activities:
Deferred income taxes and investment tax credits			13
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			(72)
Net Income			130
Earnings attributable to common shares			129
Statement of Comprehensive Income [Abstract]
Comprehensive income			128
Cash flows from operating activities:
Deferred income taxes and investment tax credits			20
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			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		(98)	(83)	[1]
Earnings attributable to common shares	[1]	203	199	[2]
Statement of Comprehensive Income [Abstract]
Comprehensive income		203	199
Cash flows from operating activities:
Deferred income taxes and investment tax credits		80	55	[2]
Other		(5)	(7)	[2]
Net cash provided by operating activities		463	241	[2]
Cash flows from financing activities:
Net cash provided by financing activities		$ (62)	5	[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			(83)
Net Income			199
Cash flows from operating activities:
Deferred income taxes and investment tax credits			55
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			(87)
Net Income			195
Cash flows from operating activities:
Deferred income taxes and investment tax credits			59
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			4
Net Income			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.