Long-Term Debt and Financing Obligations	6 Months Ended
Jun. 30, 2012
Long-Term Debt and Financing Obligations [Abstract]
Long-term Debt [Text Block]	Long-Term Debt and Financing Obligations Revolving Credit Facility. The Company maintains a revolving credit facility (“RCF”) for working capital and general corporate purposes and financing of nuclear fuel through the Rio Grande Resources Trust (the “RGRT”). RGRT is the trust through which the Company finances its portion of nuclear fuel for Palo Verde and is consolidated in the Company's financial statements. The RCF has a term ending September 2016. On March 29, 2012, the Company and the Bank of New York Mellon Trust Company, N.A., as trustee of the RGRT, entered into the Incremental Facility Assumption Agreement (the “Assumption Agreement”) related to the RCF with JP Morgan Chase Bank, N.A., as administrative agent and issuing bank, Union Bank, N.A., as syndication agent, and various lending banks party thereto. The Assumption Agreement provides for the Company's exercise in full of the accordion feature provided for under the RCF, increasing the aggregate unsecured borrowing available from $200 million to $300 million. In addition, the Assumption Agreement reflects the addition of a new lender under the RCF. No other material modifications were made to the terms and conditions of the RCF. The total amount borrowed for nuclear fuel by RGRT was $144.8 million at June 30, 2012, of which $34.8 million had been borrowed under the RCF and $110 million was borrowed through senior notes. At December 31, 2011, the total amount borrowed for nuclear fuel by RGRT was $123.4 million of which $13.4 million was borrowed under the RCF and $110 million was borrowed through senior notes. Interest costs on borrowings to finance nuclear fuel are accumulated by RGRT and charged to the Company as fuel is consumed and recovered through fuel recovery charges. At June 30, 2012, $76.0 million was outstanding under the RCF for working capital or general corporate purposes. At December 31, 2011, $20.0 million was outstanding under the RCF for working capital or general corporate purposes. Pollution Control Bonds (“PCBs”). The Company has four series of tax exempt unsecured PCBs in aggregate principal amount of $193.1 million. The 4.00% 2002 Series A with a principal amount of $33.3 million is shown as current maturities of long-term debt on the Company's June 30, 2012 and December 31, 2011 balance sheets. On August 1, 2012, the Company completed a refunding transaction where it purchased these PCBs. The Company may remarket these PCBs at a future date depending on financing needs and market conditions.

Long-Term Debt and Financing Obligations

Revolving Credit Facility. The Company maintains a revolving credit facility (“RCF”) for working capital and general corporate purposes and financing of nuclear fuel through the Rio Grande Resources Trust (the “RGRT”). RGRT is the trust through which the Company finances its portion of nuclear fuel for Palo Verde and is consolidated in the Company's financial statements. The RCF has a term ending September 2016. On March 29, 2012, the Company and the Bank of New York Mellon Trust Company, N.A., as trustee of the RGRT, entered into the Incremental Facility Assumption Agreement (the “Assumption Agreement”) related to the RCF with JP Morgan Chase Bank, N.A., as administrative agent and issuing bank, Union Bank, N.A., as syndication agent, and various lending banks party thereto. The Assumption Agreement provides for the Company's exercise in full of the accordion feature provided for under the RCF, increasing the aggregate unsecured borrowing available from $200 million to $300 million.

In addition, the Assumption Agreement reflects the addition of a new lender under the RCF. No other material modifications were made to the terms and conditions of the RCF. The total amount borrowed for nuclear fuel by RGRT was $144.8 million at June 30, 2012, of which $34.8 million had been borrowed under the RCF and $110 million was borrowed through senior notes. At December 31, 2011, the total amount borrowed for nuclear fuel by RGRT was $123.4 million of which $13.4 million was borrowed under the RCF and $110 million was borrowed through senior notes. Interest costs on borrowings to finance nuclear fuel are accumulated by RGRT and charged to the Company as fuel is consumed and recovered through fuel recovery charges. At June 30, 2012, $76.0 million was outstanding under the RCF for working capital or general corporate purposes. At December 31, 2011, $20.0 million was outstanding under the RCF for working capital or general corporate purposes.

Pollution Control Bonds (“PCBs”). The Company has four series of tax exempt unsecured PCBs in aggregate principal amount of $193.1 million. The 4.00% 2002 Series A with a principal amount of $33.3 million is shown as current maturities of long-term debt on the Company's June 30, 2012 and December 31, 2011 balance sheets. On August 1, 2012, the Company completed a refunding transaction where it purchased these PCBs. The Company may remarket these PCBs at a future date depending on financing needs and market conditions.