INVESTMENTS IN UNCONSOLIDATED ENTITIES (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended		3 Months Ended			9 Months Ended
	Aug. 09, 2011	Apr. 15, 2011	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2011	Sep. 30, 2011
Investment In Joint Venture Disclosure [Abstract]
Distributions from RBS Sempra Commodities LLP	$ 98	$ 329
Investment in RBS Sempra Commodities LLP			126
Pretax equity earnings (losses) from RBS Sempra Commodities LLP					(16)	(24)
Loss on impairment of RBS Sempra Commodities LLP					(16)	(16)
Loss on impairment of RBS Sempra Commodities LLP, after tax					(10)	(10)
Schedule of Equity Method Investments [Line Items]
Sempra Renewables' Equity Method Investments In Joint Ventures			296
Loss on impairment of investment in Rockies Express			100	300
Loss on impairment of investment in Rockies Express, after tax			60	179
Investment in Rockies Express			369
Rockies Express [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage in equity method investee			25.00%
Ownership percentage of minority partner in equity method investee			25.00%
Ownership percentage of operating partner in equity method investee			50.00%
Flat Ridge 2 [Member]
Schedule of Equity Method Investments [Line Items]
Sempra Renewables' Equity Method Investments In Joint Ventures			$ 249