FAIR VALUE MEASUREMENTS 3 (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 85,000,000	$ 47,000,000	$ 99,000,000	$ 61,000,000
Realized and unrealized gains (losses)	3,000,000	1,000,000	9,000,000	(2,000,000)
Allocated transmission instruments	9,000,000	15,000,000	10,000,000	15,000,000
Settlements	(10,000,000)	(6,000,000)	(31,000,000)	(17,000,000)
Balance at end of period	87,000,000	57,000,000	87,000,000	57,000,000
Change in unrealized gains (losses) relating to instruments still held at period end	0	2,000,000	0	1,000,000
CRR Auction Rate Per MWh, Minimum	(6,000,000)	(8,000,000)	(6,000,000)	(8,000,000)
CRR Auction Rate Per MWh, Maximum	$ 12,000,000	$ 8,000,000	$ 12,000,000	$ 8,000,000