OTHER FINANCIAL DATA - COMPREHENSIVE INCOME AND EQUITY (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014	Dec. 31, 2014
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				$ 12,100	[1]	$ 11,850
Comprehensive income (loss)				667		511
Share-based compensation expense				26		21
Common stock dividends declared				(347)		(324)
Preferred dividends of subsidiary		$ (1)	$ (1)	(1)		(1)
Issuance of common stock				59		42
Tax benefit related to share-based compensation				52		13
Repurchases of common stock				(66)		(37)
Noncontrolling Interest Increase				1		1
Distributions to noncontrolling interests				(16)		(25)
Equity, end of period		12,475	12,051	12,475		12,051
Ownership Interests Held By Others [Line Items]
Amount of ownership interests held by others		772		772			$ 754
San Diego Gas and Electric Company [Member]
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				4,992	[1]	4,719
Comprehensive income (loss)				282		230
Distributions to noncontrolling interests				(8)		(13)
Equity, end of period		5,266	4,936	5,266		4,936
Southern California Gas Company [Member]
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				2,781	[1]	2,549
Comprehensive income (loss)				285		159
Preferred dividend requirements		(1)	(1)	(1)		(1)
Equity, end of period		3,065	2,707	3,065		2,707
Total Shareholders' Equity
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				11,326		11,008
Comprehensive income (loss)				634		472
Share-based compensation expense				26		21
Common stock dividends declared				(347)		(324)
Preferred dividends of subsidiary				(1)		(1)
Issuance of common stock				59		42
Tax benefit related to share-based compensation				52		13
Repurchases of common stock				(66)		(37)
Noncontrolling Interest Increase				0		0
Distributions to noncontrolling interests				0		0
Equity, end of period		11,683	11,194	11,683		11,194
Total Shareholders' Equity | San Diego Gas and Electric Company [Member]
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				4,932		4,628
Comprehensive income (loss)				273		223
Distributions to noncontrolling interests				0		0
Equity, end of period		5,205	4,851	5,205		4,851
Noncontrolling Interests [Member]
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				774		842
Comprehensive income (loss)				33		39
Share-based compensation expense				0		0
Common stock dividends declared				0		0
Preferred dividends of subsidiary				0		0
Issuance of common stock				0		0
Tax benefit related to share-based compensation				0		0
Repurchases of common stock				0		0
Noncontrolling Interest Increase				1		1
Distributions to noncontrolling interests				(16)		(25)
Equity, end of period		792	857	792		857
Noncontrolling Interests [Member] | San Diego Gas and Electric Company [Member]
Comprehensive Income Disclosure [Line Items]
Equity, beginning of period				60		91
Comprehensive income (loss)				9		7
Distributions to noncontrolling interests				(8)		(13)
Equity, end of period		$ 61	$ 85	$ 61		$ 85
Ownership Interests Held By Others, Bay Gas Storage Company [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		9.10%		9.10%			9.10%
Amount of ownership interests held by others		$ 24		$ 24			$ 23
Ownership Interests Held By Others, Southern Gas Transmission [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		49.00%		49.00%			49.00%
Amount of ownership interests held by others		$ 1		$ 1			$ 1
Ownership Interests Held By Others, Liberty Gas Storage [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		25.00%		25.00%			25.00%
Amount of ownership interests held by others		$ 14		$ 14			$ 14
Ownership Interests Held By Others, Tecsur [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		9.80%		9.80%			9.80%
Amount of ownership interests held by others		$ 3		$ 3			$ 4
Ownership Interests Held By Others, Luz Del Sur [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		16.40%		16.40%			16.40%
Amount of ownership interests held by others		$ 171		$ 171			$ 177
Ownership Interests Held By Others, Chilquinta Energia [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others, minimum	[2]	23.50%		23.50%			23.60%
Percent of ownership held by others, maximum	[2]	43.40%		43.40%			43.40%
Amount of ownership interests held by others	[2]	$ 22		$ 22			$ 23
Otay Mesa VIE [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		100.00%		100.00%			100.00%
Amount of ownership interests held by others		$ 61		$ 61			$ 60
Ownership Interests Held By Others IEnova [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others		18.90%		18.90%			18.90%
Amount of ownership interests held by others		$ 476		$ 476			$ 452

[1] Derived from audited financial statements.

[2] Chilquinta Energía has four subsidiaries with noncontrolling interests held by others. Percentage range reflects the highest and lowest ownership percentages amongst these subsidiaries.