Significant Accounting Policies and Responsibility for Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Condensed Consolidated Financial Statements of each of PNMR, PNM, and TNMP include their accounts and those of subsidiaries in which that entity owns a majority voting interest. PNM also consolidates Valencia (Note 5) and, through January 15, 2016, the PVNGS Capital Trust. PNM owns undivided interests in several jointly-owned power plants and records its pro-rata share of the assets, liabilities, and expenses for those plants. The agreements for the jointly-owned plants provide that if an owner were to default on its payment obligations, the non-defaulting owners would be responsible for their proportionate share of the obligations of the defaulting owner. In exchange, the non-defaulting owners would be entitled to their proportionate share of the generating capacity of the defaulting owner. There have been no such payment defaults under any of the agreements for the jointly-owned plants. PNMR shared services’ administrative and general expenses, which represent costs that are primarily driven by corporate level activities, are charged to the business segments. These services are billed at cost. Other significant intercompany transactions between PNMR, PNM, and TNMP include interest and income tax sharing payments, as well as equity transactions. All intercompany transactions and balances have been eliminated.
Dividends on Common Stock	Dividends on Common Stock Dividends on PNMR’s common stock are declared by its Board. The timing of the declaration of dividends is dependent on the timing of meetings and other actions of the Board. This has historically resulted in dividends considered to be attributable to the second quarter of each year being declared through actions of the Board during the third quarter of the year.
New Accounting Pronouncements	New Accounting Pronouncements Information concerning recently issued accounting pronouncements that have not been adopted by the Company is presented below. Accounting Standards Update 2014-09 – Revenue from Contracts with Customers (Topic 606) In May 2014, the FASB issued ASU No. 2014-09. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. When it becomes effective, the new standard will replace most existing revenue recognition guidance in GAAP. In August 2015, the FASB issued a one-year deferral in the effective date. Since the issuance of ASU No. 2014-09, the FASB also has issued additional ASUs that clarify implementation guidance regarding principal versus agent considerations, licensing, and identifying performance obligations, as well as adding certain additional practical expedients. The Company must adopt ASU 2014-09 beginning on January 1, 2018. Early adoption would be permitted beginning January 1, 2017. The standard permits the use of either the retrospective or cumulative effect transition method. The Company has not yet selected a transition method although it is unlikely the Company would elect to early adopt the new standard. The Company is analyzing the impacts this new standard will have on its consolidated financial statements and related disclosures, but has not determined the effect of the standard on its financial reporting. Accounting Standards Update 2014-15 – Presentation of Financial Statements – Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In August 2014, the FASB issued ASU No. 2014-15, which requires management to evaluate whether there is substantial doubt about a company’s ability to continue as a going concern in connection with the preparation of financial statements for each annual and interim reporting period. Disclosure requirements associated with management’s evaluation are also outlined in the new guidance. The new standard is effective for the Company for reporting periods ending after December 15, 2016, with early adoption permitted. The Company anticipates adopting this standard as of December 31, 2016. The Company is analyzing the impacts of this new standard, but does not anticipate it will have a significant impact on the Company’s financial statements. Accounting Standards Update 2016-01 – Financial Instruments (Subtopic 825-10) – Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU No. 2016-01, which makes targeted improvements to GAAP regarding financial instruments. The new standard eliminates the requirement to classify investments in equity securities with readily determinable fair values into trading or available-for-sale categories and will require those equity securities to be measured at fair value with changes in fair value recognized in net income rather than in OCI. Also, the new standard will revise certain presentation and disclosure requirements. Under the new standard, accounting for investments in debt securities remains essentially unchanged. The new standard will be effective for the Company beginning on January 1, 2018. Early adoption of the standard is permitted. The Company is in the process of analyzing the impacts of this new standard. Accounting Standards Update 2016-02 – Leases (Topic 842) In February 2016, the FASB issued ASU No. 2016-02, which will change how lessees account for leases. The ASU will require that a liability be recorded on the balance sheet for all leases based on the present value of future lease obligations. A corresponding right-of-use asset will also be recorded. Amortization of the lease obligation and the right-of-use asset for certain leases, primarily those classified as operating leases, will be on a straight-line basis, which is not expected to have a significant impact on the statements of earnings or cash flows, whereas other leases will be required to be accounted for as financing arrangements similar to the accounting treatment for capital leases under current GAAP. Also, the new standard will revise certain disclosure requirements. The new standard will be effective for the Company beginning on January 1, 2019. Early adoption of the standard is permitted. At adoption of the ASU, leases will be recognized and measured as of the earliest period presented using a modified retrospective approach. The Company is in the process of analyzing the impacts of this new standard. Accounting Standards Update 2016-09 – Compensation – Stock Compensation (Topic 718) In March 2016, the FASB issued ASU No. 2016-09. The ASU simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. Currently, tax benefits resulting from deductions in excess of compensation cost on vested restricted stock and performance awards and on exercised stock options (“excess tax benefits”) are recorded to equity provided these benefits reduce taxes payable. Tax deficiencies resulting from deductions related to awards, which are below realized compensation cost upon vesting and on canceled stock options are recorded to equity. The Company has not recorded excess tax benefits to equity since 2009 because it is in a net operating loss position for income tax purposes. Upon implementation of the new standard, the Company will record a cumulative effect adjustment to recognize excess tax benefits that have not been recorded due to the Company’s net operating loss. Subsequent to implementation, all excess tax benefits and deficiencies will be recorded to tax expense on the Condensed Consolidated Income Statements and classified as cash flows from operating activities on the Condensed Consolidated Statements of Cash Flows. The Company continues its process of analyzing the impacts of this new standard, but does not believe there will be any retrospective impacts to its financial statements. The Company anticipates adopting the new standard upon its required effective date of January 1, 2017. Accounting Standards Update 2016-13 – Financial Instruments – Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU No. 2016-13. The ASU changes the way entities recognize impairment of many financial assets, including accounts receivable and investments in debt securities, by requiring immediate recognition of estimated credit losses expected to occur over their remaining lives. The new standard is effective for the Company beginning on January 1, 2020. Early adoption is permitted beginning on January 1, 2019. The Company is in the process of analyzing the impacts of this new standard. Accounting Standards Update 2016-15 – Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU No. 2016-15. The ASU eliminates diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The new standard is effective for the Company beginning on January 1, 2018. Early adoption is permitted including adoption in an interim period. The Company is in the process of analyzing the impacts of this new standard, but does not anticipate it will have a significant impact on the Company’s financial statements.
Variable Interest Entity	GAAP determines how an enterprise evaluates and accounts for its involvement with variable interest entities, focusing primarily on whether the enterprise has the power to direct the activities that most significantly impact the economic performance of a variable interest entity (“VIE”). GAAP also requires continual reassessment of the primary beneficiary of a VIE.