OTHER FINANCIAL DATA - INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit)	$ 68	$ (32)	$ 269	$ 85
Effective income tax rate	18.00%	(32.00%)	20.00%	18.00%
Remeasurement of equity method investments			277
State income tax expense related to our exit from the RBS Sempra Commodities business		11		11
Income tax expense (benefit) due to Mexican currency translation and inflation adjustments	(30)	9	(17)	16
Write-down of deferred tax assets related to other post retirement benefits				16
Non-taxable gain related to our share of the RBS Sempra Commodities sale to J.P. Morgan Ventures		175		175
San Diego Gas and Electric Company and Subsidiary [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit)	63	56	154	131
Effective income tax rate	32.00%	35.00%	35.00%	36.00%
Write-down of deferred tax assets related to other post retirement benefits				3
Southern California Gas Company [Member]
Income Tax Expense And Effective Income Tax Rates Disclosure [Line Items]
Income tax expense (benefit)	41	42	106	132
Effective income tax rate	34.00%	35.00%	34.00%	38.00%
Write-down of deferred tax assets related to other post retirement benefits				$ 13