Intangible Asset (Details) (USD $)	12 Months Ended								12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Right to bill and collect storm recovery charges from customers and financing costs [Member]	Dec. 31, 2011 Right to bill and collect storm recovery charges from customers and financing costs [Member]	Dec. 31, 2008 Right to bill and collect storm recovery charges from customers and financing costs [Member]	Dec. 31, 2008 Right to bill and collect storm recovery charges from customers [Member]	Dec. 31, 2008 Financing costs [Member]	Dec. 31, 2008 Minimum [Member] Right to bill and collect storm recovery charges from customers and financing costs [Member]	Dec. 31, 2008 Maximum [Member] Right to bill and collect storm recovery charges from customers and financing costs [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset						$ 177,500,000	$ 176,000,000	$ 1,500,000
Intangible asset expected useful life, minimum (in years)									12 years	15 years
Amortization expense	13,100,000	11,800,000	11,700,000
Intangible asset, net [Abstract]
Gross carrying amount				177,537,000	177,537,000
Accumulated amortization				56,992,000	43,942,000
Intangible asset	120,545,000	133,595,000		120,545,000	133,595,000
Expected amortization expense
For the year ending December 31, 2013				14,026,000
For the year ending December 31, 2014				14,931,000
For the year ending December 31, 2015				15,876,000
For the year ending December 31, 2016				16,864,000
For the year ending December 31, 2017				18,009,000
After 2017				$ 40,839,000