Optim Energy	9 Months Ended
Sep. 30, 2011
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments Disclosure [Text Block]	Optim Energy Information concerning Optim Energy is discussed in Note 22 of Notes to Consolidated Financial Statements in the 2010 Annual Reports on Form 10-K. In January 2007, Optim Energy was created by PNMR and ECJV, a wholly owned subsidiary of Cascade, to serve expanding U.S. markets, principally the areas of Texas covered by ERCOT. PNMR and ECJV each had a 50 percent ownership interest in Optim Energy, a limited liability company. Impairment and Restructuring Beginning in 2009 and continuing throughout 2010, Optim Energy was affected by adverse market conditions, primarily low natural gas and power prices. In addition to these adverse market conditions, reported sales of electric generating resources within the ERCOT market area were transacted at prices (per KW of generating capacity) that were substantially below the amounts recorded for the electric generating plants underlying PNMR’s investment in Optim Energy. Under GAAP, these factors were indicators of impairment that required an impairment analysis to be performed by PNMR of its investment in Optim Energy as of December 31, 2010. PNMR’s analysis indicated that its entire investment in Optim Energy was impaired and PNMR reduced the carrying value of its investment in Optim Energy to zero at December 31, 2010, resulting in a pre-tax impairment loss of $188.2 million. In accordance with GAAP, PNMR has not recorded losses associated with its investment in Optim Energy in 2011 as PNMR has no contractual requirement or agreement to provide Optim Energy with additional financial resources. As a result of the adverse market conditions described above, PNMR (in collaboration with Optim Energy and ECJV) assessed various strategic alternatives relating to Optim Energy. On September 23, 2011, PNMR, ECJV, and Cascade agreed to restructure Optim Energy and ECJV made an equity contribution to Optim Energy in exchange for an increased ownership interest, which resulted in PNMR's ownership in Optim Energy being reduced from 50% to 1%. Optim Energy's debt is non-recourse to PNMR. As part of this transaction, PNMR did not make any equity contribution to Optim Energy nor will it be required to make any contribution in the future. From January 1, 2012 through December 31, 2013, ECJV has the option to purchase PNMR's 1% ownership interest in Optim Energy at fair market value and, if that option is not exercised, PNMR would have the option from June 30, 2014 to December 31, 2015 to sell its 1% ownership interest in Optim Energy to ECJV at fair market value. PNMR accounted for its investment in Optim Energy using the equity method of accounting until September 23, 2011 and is using the cost method thereafter. The fair value of PNMR's 1% ownership interest in Optim Energy was de minimis at September 30, 2011. PNMR Services Company has been providing certain corporate services to Optim Energy and will continue to provide certain services at least through the end of 2011 and after that with respect to certain tax matters. Operational Information As discussed above, PNMR fully impaired its investment in Optim Energy at December 31, 2010 and has not recognized losses of Optim Energy from January 1, 2011 through September 23, 2011 when PNMR ceased to account for its investment using the equity method of accounting. Accordingly, Optim Energy has no impact on PNMR's 2011 balance sheet, statement of earnings, and statement of cash flows. Therefore, summarized financial information for Optim Energy is not presented. Optim Energy had net earnings (loss) of $7.6 million and $(6.8) million in the three months and nine months ended September 30, 2010. PNMR recognized net earnings (loss) from Optim Energy of $2.5 million and $(5.7) million in the three months and nine months ended September 30, 2010. Such amounts include amortization of a basis difference between PNMR's recorded investment in Optim Energy and 50 percent of Optim Energy’s equity.

Optim Energy

Information concerning Optim Energy is discussed in Note 22 of Notes to Consolidated Financial Statements in the 2010 Annual Reports on Form 10-K. In January 2007, Optim Energy was created by PNMR and ECJV, a wholly owned subsidiary of Cascade, to serve expanding U.S. markets, principally the areas of Texas covered by ERCOT. PNMR and ECJV each had a 50 percent ownership interest in Optim Energy, a limited liability company.

Impairment and Restructuring

Beginning in 2009 and continuing throughout 2010, Optim Energy was affected by adverse market conditions, primarily low natural gas and power prices. In addition to these adverse market conditions, reported sales of electric generating resources within the ERCOT market area were transacted at prices (per KW of generating capacity) that were substantially below the amounts recorded for the electric generating plants underlying PNMR’s investment in Optim Energy. Under GAAP, these factors were indicators of impairment that required an impairment analysis to be performed by PNMR of its investment in Optim Energy as of December 31, 2010. PNMR’s analysis indicated that its entire investment in Optim Energy was impaired and PNMR reduced the carrying value of its investment in Optim Energy to zero at December 31, 2010, resulting in a pre-tax impairment loss of $188.2 million. In accordance with GAAP, PNMR has not recorded losses associated with its investment in Optim Energy in 2011 as PNMR has no contractual requirement or agreement to provide Optim Energy with additional financial resources.

As a result of the adverse market conditions described above, PNMR (in collaboration with Optim Energy and ECJV) assessed various strategic alternatives relating to Optim Energy. On September 23, 2011, PNMR, ECJV, and Cascade agreed to restructure Optim Energy and ECJV made an equity contribution to Optim Energy in exchange for an increased ownership interest, which resulted in PNMR's ownership in Optim Energy being reduced from 50% to 1%. Optim Energy's debt is non-recourse to PNMR. As part of this transaction, PNMR did not make any equity contribution to Optim Energy nor will it be required to make any contribution in the future. From January 1, 2012 through December 31, 2013, ECJV has the option to purchase PNMR's 1% ownership interest in Optim Energy at fair market value and, if that option is not exercised, PNMR would have the option from June 30, 2014 to December 31, 2015 to sell its 1% ownership interest in Optim Energy to ECJV at fair market value. PNMR accounted for its investment in Optim Energy using the equity method of accounting until September 23, 2011 and is using the cost method thereafter. The fair value of PNMR's 1% ownership interest in Optim Energy was de minimis at September 30, 2011. PNMR Services Company has been providing certain corporate services to Optim Energy and will continue to provide certain services at least through the end of 2011 and after that with respect to certain tax matters.

Operational Information

As discussed above, PNMR fully impaired its investment in Optim Energy at December 31, 2010 and has not recognized losses of Optim Energy from January 1, 2011 through September 23, 2011 when PNMR ceased to account for its investment using the equity method of accounting. Accordingly, Optim Energy has no impact on PNMR's 2011 balance sheet, statement of earnings, and statement of cash flows. Therefore, summarized financial information for Optim Energy is not presented.

Optim Energy had net earnings (loss) of $7.6 million and $(6.8) million in the three months and nine months ended September 30, 2010. PNMR recognized net earnings (loss) from Optim Energy of $2.5 million and $(5.7) million in the three months and nine months ended September 30, 2010. Such amounts include amortization of a basis difference between PNMR's recorded investment in Optim Energy and 50 percent of Optim Energy’s equity.