OTHER FINANCIAL DATA - VARIABLE INTEREST ENTITIES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Variable Interest Entities Disclosure [Abstract]
Secured debt of variable interest entity	$ 350		$ 350
Amounts Associated With Variable Interest Entities, Cost of Electric Fuel And Purchased Power	(21)	(9)	(40)	(26)
Amounts Associated With Variable Interest Entities, Operation And Maintenance	7	18	11	22
Amounts Associated With Variable Interest Entities, Depreciation And Amortization	6	7	12	13
Amounts Associated With Variable Interest Entities, Total Operating Expenses	(8)	16	(17)	9
Amounts Associated With Variable Interest Entities, Operating Income	8	(16)	17	(9)
Amounts Associated With Variable Interest Entities, Other Income (Expense), Net	(1)	(4)	(1)	(4)
Amounts Associated With Variable Interest Entities, Interest Expense	(2)	1	(5)	(2)
Amounts Associated With Variable Interest Entities, Net Income	5	(19)	11	(15)
Amounts Associated With Variable Interest Entities, (Earnings) Losses Attributable Noncontrolling Interests	$ (5)	$ 19	$ (11)	$ 15