OTHER FINANCIAL DATA - VARIABLE INTEREST ENTITIES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Variable Interest Entities Disclosure [Abstract]
Equity of variable interest entity	$ 79		$ 79		$ 76
Secured debt of variable interest entity	337		337
Amounts Associated With Variable Interest Entities, Operating Revenues, Electric	(4)	0	0	0
Amounts Associated With Variable Interest Entities, Operating Revenues, Gas	0	0	0	0
Amounts Associated With Variable Interest Entities, Total Operating Revenues	(4)	0	0	0
Amounts Associated With Variable Interest Entities, Cost of Electric Fuel And Purchased Power	(27)	(26)	(65)	(66)
Amounts Associated With Variable Interest Entities, Operation And Maintenance	7	4	33	15
Amounts Associated With Variable Interest Entities, Depreciation And Amortization	7	7	20	19
Amounts Associated With Variable Interest Entities, Total Operating Expenses	(13)	(15)	(12)	(32)
Amounts Associated With Variable Interest Entities, Operating Income (Loss)	9	15	12	32
Amounts Associated With Variable Interest Entities, Other Income (Expense), Net	0	0	0	(1)
Amounts Associated With Variable Interest Entities, Interest Expense	(4)	(3)	(11)	(8)
Amounts Associated With Variable Interest Entities, Net Income (Loss)	5	12	1	23
Amounts Associated With Variable Interest Entities, (Earnings) Losses Attributable Noncontrolling Interests	(5)	(12)	(1)	(23)
Amounts Associated With Variable Interest Entities, Earnings	$ 0	$ 0	$ 0	$ 0