Intangible Asset (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	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] Y	Dec. 31, 2010 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]
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
Intangible asset expected useful life, maximum (in years)					15
Amortization expense	11,800,000	11,700,000	10,700,000
Intangible asset, net [Abstract]
Gross carrying amount				177,537,000		177,537,000
Accumulated amortization				43,942,000		32,163,000
Intangible asset	133,595,000	145,374,000		133,595,000		145,374,000
Expected amortization expense
For the year ending December 31, 2012				13,167,000
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
After 2016				$ 58,731,000