Regulatory Matters (Details 1) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Changes in PPFAC related accounts and impacts on revenue and expense
Revenue subject to refund	$ (21,000,000)	$ (21,000,000)		$ (36,000,000)
PPFAC (current and non-current)	66,000,000	66,000,000		58,000,000
CTC Revenue Refunded	(13,000,000)	(15,112,000)	(5,339,000)
Reduction to fuel and purchased power expense due to total PPFAC		$ 8,000,000