FAIR VALUE (Details 3) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of period	$ (200,000)	$ (7,300,000)	$ (5,400,000)	$ (5,700,000)
Net realized (losses) gains included in earnings	1,500,000	(600,000)	2,500,000	1,400,000
Net unrealized (losses) gains recorded as regulatory assets or liabilities	(3,700,000)	2,100,000	1,900,000	1,200,000
Purchases	0	0	3,200,000	2,800,000
Sales	0	0	(100,000)	(100,000)
Settlements	3,000,000	(1,800,000)	(1,500,000)	(7,200,000)
Balance at the end of period	600,000	(7,600,000)	600,000	(7,600,000)
Unrealized Gain (Loss) Recognized in Income
Impact on earnings of unrealized gains and losses on Level 3 derivatives	0	0	0	0
FTRs
Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of period	2,100,000	2,500,000	1,100,000	1,200,000
Net realized (losses) gains included in earnings	1,500,000	(600,000)	2,500,000	1,400,000
Net unrealized (losses) gains recorded as regulatory assets or liabilities	800,000	0	(300,000)	(300,000)
Purchases	0	0	3,200,000	2,800,000
Sales	0	0	(100,000)	(100,000)
Settlements	(2,600,000)	(200,000)	(4,600,000)	(3,300,000)
Balance at the end of period	1,800,000	1,700,000	1,800,000	1,700,000
Coal contract
Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of period	(2,300,000)	(9,800,000)	(6,500,000)	(6,900,000)
Net realized (losses) gains included in earnings	0	0	0	0
Net unrealized (losses) gains recorded as regulatory assets or liabilities	(4,500,000)	2,100,000	2,200,000	1,500,000
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	5,600,000	(1,600,000)	3,100,000	(3,900,000)
Balance at the end of period	$ (1,200,000)	$ (9,300,000)	$ (1,200,000)	$ (9,300,000)