OTHER FINANCIAL DATA - COMPREHENSIVE INCOME AND EQUITY (Details) In Millions, except Share data, unless otherwise specified	0 Months Ended		3 Months Ended																			3 Months Ended
	Mar. 31, 2013 USD ($)	Mar. 31, 2013 MXN	Mar. 31, 2013 USD ($)		Mar. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Bay Gas Storage Company [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Bay Gas Storage Company [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Southern Gas Transmission [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Southern Gas Transmission [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Liberty Gas Storage [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Liberty Gas Storage [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Tecsur [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Tecsur [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Luz Del Sur [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Luz Del Sur [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Chilquinta Energia [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Chilquinta Energia [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others, Otay Mesa VIE [Member] USD ($)	Dec. 31, 2012 Ownership Interests Held By Others, Otay Mesa VIE [Member] USD ($)	Mar. 31, 2013 Ownership Interests Held By Others IEnova [Member] USD ($)	Mar. 31, 2013 San Diego Gas and Electric Company and Subsidiary [Member] USD ($)		Mar. 31, 2012 San Diego Gas and Electric Company and Subsidiary [Member] USD ($)	Mar. 31, 2013 Southern California Gas Company [Member] USD ($)	Mar. 31, 2012 Southern California Gas Company [Member] USD ($)	Mar. 31, 2013 Total Shareholders' Equity USD ($)	Mar. 31, 2012 Total Shareholders' Equity USD ($)	Mar. 31, 2013 Total Shareholders' Equity San Diego Gas and Electric Company and Subsidiary [Member] USD ($)	Mar. 31, 2012 Total Shareholders' Equity San Diego Gas and Electric Company and Subsidiary [Member] USD ($)	Mar. 31, 2013 Noncontrolling Interests USD ($)	Mar. 31, 2012 Noncontrolling Interests USD ($)	Mar. 31, 2013 Noncontrolling Interests San Diego Gas and Electric Company and Subsidiary [Member] USD ($)	Mar. 31, 2012 Noncontrolling Interests San Diego Gas and Electric Company and Subsidiary [Member] USD ($)
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period			$ 10,683	[1]	$ 10,178																	$ 4,298	[1]	$ 3,841	$ 2,235		$ 10,282	$ 9,775	$ 4,222	$ 3,739	$ 401	$ 403	$ 76	$ 102
Comprehensive income, net of income tax
Net income			178		251																	81		112	46	66	180	238	92	106	(2)	13	(11)	6
Foreign currency translation adjustments			6		71																						10	67			(4)	4
Financial instruments			(11)		3																	3					(14)	3			3		3
Net actuarial gain			3		1																						3	1
Share-based compensation expense			10		11																						10	11
Common stock dividends declared			(153)		(144)																						(153)	(144)
Preferred dividend requirements																						(1)		(1)					(1)	(1)
Preferred dividends of subsidiaries			(2)		(2)																						(2)	(2)
Issuance of common stock			15		13																						15	13
Tax benefit related to share-based compensation			2																								2
Repurchases of common stock			(45)		(16)																						(45)	(16)
Common stock released from ESOP					6																							6
Sale of noncontrolling interests, net of offering costs			574																								135				439
Equity contributed by noncontrolling interests			4																			4									4		4
Distributions to noncontrolling interests			(3)		(2)																										(3)	(2)
Equity, end of period	11,261		11,261		10,370																	4,385		3,952	2,281		10,423	9,952	4,313	3,844	838	418	72	108
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others							9.10%		49.00%		25.00%		9.80%		20.20%				100.00%		18.90%
Percent of ownership held by others, minimum																	24.40%
Percent of ownership held by others, maximum																	43.40%
Amount of ownership interests held by others	818		818			381	20	20	1	1	15	15	4	4	237	236	30	29	72	76	439
Sale Of Noncontrolling Interests [Abstract]
Proceeds From Sale Of Noncontrolling Interests Net	$ 574	7,100	$ 574
Common stock shares issued	218,110,500	218,110,500	218,110,500
Share price	$ 2.75	34	$ 2.75
Minority interest ownership percentage by parent	81.10%	81.10%	81.10%
Foreign currency exchange rate pesos to US dollars	12.3841	12.3841	12.3841

[1] Derived from audited financial statements.