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Administrative Expense Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Retirement of treasury stock Treasury Stock, Retired, Cost Method, Amount Fixed-cost per day payments (dollars per MWd) Fixed-Cost Price Per MW, Per Day Fixed-Cost Price Per MW, Per Day Estimated Useful Life (years) Property, Plant and Equipment, Useful Life Environmental products Inventory, Environmental Products, Net Of Reserves Inventory, Environmental Products, Net Of Reserves Subsequent Event Subsequent Event [Member] Schedule of Significant Inputs and Assumptions of Fair Value Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Equity securities, Fair Value Equity securities Equity Securities, FV-NI Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total 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