OTHER FINANCIAL DATA - COMPREHENSIVE INCOME AND EQUITY (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	$ 10,178	[1],[2]	$ 9,201
Comprehensive income, net of income tax
Net income	251		260	[1]
Foreign currency translation adjustments	71		(6)	[1]
Financial instruments	3		3	[1]
Net actuarial gain	1		2	[1]
Share-based compensation expense	11		11
Common stock dividends declared	(144)		(115)
Preferred dividends of subsidiaries	(2)		(2)	[1]
Issuance of common stock	13		15
Tax benefit related to share-based compensation			2
Repurchases of common stock	(16)		(17)
Common stock released from ESOP	6		7
Equity contributed by noncontrolling interests			1
Distributions to noncontrolling interests	(2)
Equity, end of period	10,370		9,362
Other Comprehensive Income (Loss), Tax [Abstract]
Financial instruments, income tax expense (benefit)	3		1
Net actuarial gain, income tax expense (benefit)	1		1
Ownership Interests Held By Others [Line Items]
Amount of ownership interests held by others	398				383
Ownership Interests Held By Others, Bay Gas Storage Company [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	9.00%	[3]
Amount of ownership interests held by others	18	[3]			17	[3]
Ownership Interests Held By Others, Southern Gas Transmission [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	49.00%	[3]
Amount of ownership interests held by others	1	[3]			1	[3]
Ownership Interests Held By Others, Liberty Gas Storage [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	25.00%	[3]
Amount of ownership interests held by others	9	[3]			9	[3]
Ownership Interests Held By Others, Tecsur [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	10.00%
Amount of ownership interests held by others	3				4
Ownership Interests Held By Others, Luz Del Sur [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	20.00%
Amount of ownership interests held by others	222				216
Ownership Interests Held By Others, Chilquinta Energia [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others, minimum	15.00%
Percent of ownership held by others, maximum	43.00%
Amount of ownership interests held by others	37				34
Ownership Interests Held By Others, Otay Mesa VIE [Member]
Ownership Interests Held By Others [Line Items]
Percent of ownership held by others	100.00%
Amount of ownership interests held by others	108				102
San Diego Gas and Electric Company and Subsidiary [Member]
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	3,841	[2]	3,221
Comprehensive income, net of income tax
Net income	112		94
Financial instruments			1
Preferred stock dividends declared	(1)		(1)
Capital contribution			200
Equity contributed by noncontrolling interests			1
Equity, end of period	3,952		3,516
Southern California Gas Company [Member]
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	2,193
Comprehensive income, net of income tax
Net income	66		68
Equity, end of period	2,209
Total Shareholders' Equity
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	9,775		8,990
Comprehensive income, net of income tax
Net income	238		256	[1]
Foreign currency translation adjustments	67		(6)	[1]
Financial instruments	3		2	[1]
Net actuarial gain	1		2	[1]
Share-based compensation expense	11		11
Common stock dividends declared	(144)		(115)
Preferred dividends of subsidiaries	(2)		(2)	[1]
Issuance of common stock	13		15
Tax benefit related to share-based compensation			2
Repurchases of common stock	(16)		(17)
Common stock released from ESOP	6		7
Equity, end of period	9,952		9,145
Other Comprehensive Income (Loss), Tax [Abstract]
Financial instruments, income tax expense (benefit)	3		1
Net actuarial gain, income tax expense (benefit)	1		1
Total Shareholders' Equity | San Diego Gas and Electric Company and Subsidiary [Member]
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	3,739		3,108
Comprehensive income, net of income tax
Net income	106		90
Preferred stock dividends declared	(1)		(1)
Capital contribution			200
Equity, end of period	3,844		3,397
Noncontrolling Interests
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	403		211
Comprehensive income, net of income tax
Net income	13		4	[1]
Foreign currency translation adjustments	4
Financial instruments			1	[1]
Distributions to noncontrolling interests	(2)
Equity, end of period	418		217
Noncontrolling Interests | San Diego Gas and Electric Company and Subsidiary [Member]
Comprehensive Income And Equity Disclosure [Line Items]
Equity, beginning of period	102		113
Comprehensive income, net of income tax
Net income	6		4
Financial instruments			1
Equity contributed by noncontrolling interests			1
Equity, end of period	$ 108		$ 119

[1] As adjusted for the retrospective effect of a change in accounting principle as we discuss in Note 1.

[2] Derived from audited financial statements.

[3] Part of Sempra Natural Gas.