OTHER FINANCIAL DATA - TRANSACTIONS WITH AFFILIATES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	$ 0			$ 0
Sempra Mexico Segment [Member]
Transactions With Joint Venture [Line Items]
Revenues from transactions with RBS Sempra Commodities			0			37
Cost of natural gas from transactions with RBS Sempra Commodities			3			74
Sempra Natural Gas Segment [Member]
Transactions With Joint Venture [Line Items]
Revenues from transactions with RBS Sempra Commodities			0			7
Cost of natural gas from transactions with RBS Sempra Commodities						3
San Diego Gas and Electric Company and Subsidiary [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	17			17			67
Due to affiliate, current	20			20			14
Revenues from unconsolidated affiliates	2		3	6		6
Southern California Gas Company [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	280			280			40
Revenues from unconsolidated affiliates	17		13	48		38
Affiliate Of Investee [Member] | Parent Company Member
Transactions With Affiliates Disclosure [Line Items]
Interest rate on due from affiliate, noncurrent	7.41%
Loan to unconsolidated affiliate, principal	18			18
Loan to unconsolidated affiliate, accrued interest	7			7
Due to/from Sempra Energy | San Diego Gas and Electric Company and Subsidiary [Member]
Transactions With Affiliates Disclosure [Line Items]
Income taxes due from (to) Sempra Energy	149	[1]		149	[1]		97	[1]
Due to/from Sempra Energy | Southern California Gas Company [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	280			280			23
Income taxes due from (to) Sempra Energy	15	[1]		15	[1]		17	[1]
Subsidiary Of Common Parent S D G E [Member] | Southern California Gas Company [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	0			0
Due to affiliate, current							2
Subsdiary Of Common Parent So Cal Gas [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current							2
Subsidiary Of Common Parent Other Affiliates [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current	1			1			65
Subsidiary Of Common Parent Other Affiliates [Member] | Southern California Gas Company [Member]
Transactions With Affiliates Disclosure [Line Items]
Due from affiliate, current							$ 17

[1] SDG&E and SoCalGas are included in the consolidated income tax return of Sempra Energy and are allocated income tax expense from Sempra Energy in an amount equal to that which would result from the companies’ having always filed a separate return.