DERIVATIVE INSTRUMENTS 4 (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Interest Rate Contracts [Abstract]
Losses recognized in OCI on effective portion	$ 0		$ (888,000)		$ 0		$ (752,000)
Losses reclassified from accumulated OCI into income	(112,000)	[1]	(183,000)	[1]	(224,000)	[1]	(370,000)	[1]
Gains or (losses) recognized in income on ineffective portion	0	[1]	0	[1]	0	[1]	0	[1]
Gain (loss) on energy related derivative instruments not designated as hedging instruments	(16,722,000)	[1]	3,308,000	[1]	(23,771,000)	[1]	10,279,000	[1]
Gain (loss) on interest rate derivative instruments not designated as hedging instruments	1,250,000	[2]	84,000	[2]	1,775,000	[2]	220,000	[2]
Derivative instruments not designated as hedging instruments, gain (loss), net	(15,472,000)		3,392,000		(21,996,000)		10,499,000
Realized losses, derivative instruments on energy-related contracts	1,300,000		5,700,000		200,000		10,700,000
Fair value derivative instruments with credit-risk-related features	29,500,000				29,500,000
Additional collateral, aggregate fair value	$ 25,100,000				$ 25,100,000

[1] Included in Operating Revenues - Non Utility

[2] Included in Interest Charges