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The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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Interest rate stated in the contractual debt agreement.

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Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled.

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Amount borrowed under the credit facility as of the balance sheet date.

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Financial Instruments And Investments (Long-Term Debt And Short-Term Borrowings - Narratives) (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Nuclear Fuel Financing	Dec. 31, 2011 Working Capital and General Purpose	Aug. 18, 2010 RGRT Senior Notes	Dec. 31, 2011 Senior Notes 6.00% Senior Notes, Net of Discount, due 2035	Dec. 31, 2010 Senior Notes 6.00% Senior Notes, Net of Discount, due 2035	May 01, 2005 Senior Notes 6.00% Senior Notes, Net of Discount, due 2035
Financial Instruments and Investments [Line Items]
Debt Instrument, Face Amount					$ 110,000,000			$ 400,000,000
Line of Credit Facility, Amount Outstanding			13,400,000	20,000,000
Debt Instrument, Interest Rate, Stated Percentage						6.00%	6.00%	6.00%
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	400,000
Decommissioning Fund Investments	$ 167,963,000	$ 153,878,000