FAIR VALUE MEASUREMENTS, Unobservable Input Reconciliation (Details) (Contract For Difference [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
Contract For Difference [Member]
Unobservable Input [Abstract]
Risk of non-performance, lower range (in hundredths)	0.00%	0.00%
Risk of non-performance, upper range (in hundredths)	0.64%	0.62%
Discount rate, lower range (in hundredths)	1.78%	1.75%
Discount rate, upper range (in hundredths)	2.64%	3.21%
Forward pricing, lower range (in dollars per MW)	$ 3.15	$ 1.40
Forward pricing, upper range (in dollars per MW)	$ 14.59	$ 9.83