Regulatory Matters (Details 1) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Changes in PPFAC related accounts and impacts on revenue and expense
Revenue subject to refund	$ (5,000,000)	$ (5,000,000)		$ (36,000,000)
Ppfac Asset Liability Net	59,000,000	59,000,000		54,000,000
CTC Revenue Refunded	(16,000,000)	(30,652,000)	(8,152,000)
Reduction to fuel and purchased power expense due to total PPFAC		$ 5,000,000