Income Taxes	3 Months Ended
Mar. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On January 3, 2013, the American Taxpayer Relief Act of 2012, which extended fifty percent bonus depreciation, was signed into law. Due to provisions in the act, taxes payable to the State of New Mexico for 2013 were reduced, which resulted in an impairment of New Mexico wind energy production tax credits. In accordance with GAAP, PNMR was required to record this impairment, which after federal income tax benefit, amounted to $1.5 million as additional income tax expense during the three months ended March 31, 2013. This impairment is reflected in PNMR’s Corporate and Other segment. On April 4, 2013, New Mexico House Bill 641 was signed into law. One of the provisions of the bill was to reduce the New Mexico corporate income tax rate from 7.6% to 5.9%. The rate reduction will be phased in from 2014 to 2018. In accordance with GAAP, PNMR and PNM adjusted accumulated deferred income taxes to reflect the tax rate at which the balances are expected to reverse during the period that includes the date of enactment, which was in three months ended June 30, 2013. At that time, the portion of the adjustment related to PNM’s regulated activities was recorded as a reduction in deferred tax liabilities, which was offset by an increase in a regulatory liability, on the assumption that PNM will be required to return the benefit to customers over time. The increase in the regulatory liability was $23.9 million. In addition, the portion of the adjustment that is not related to PNM’s regulated activities was recorded as a reduction in deferred tax assets and an increase in income tax expense of $1.2 million. Changes in the estimated timing of reversals of deferred tax assets and liabilities will result in refinements of the impacts of this change in tax rates being recorded periodically until 2018, when the rate reduction is fully phased in. In the three months ended March 31, 2014, PNM’s regulatory liability was reduced by $4.6 million, which increased deferred tax liabilities. Additionally, deferred tax assets not related to PNM’s regulatory activities were reduced by $0.2 million, which increased income tax expense. In 2013, the future reduction in taxes payable to the State of New Mexico resulting from the rate reduction in House Bill 641 and revisions in estimates of future taxable income resulted in a further impairment of New Mexico wind energy production tax credits. In accordance with GAAP, PNMR was required to record this impairment, which after federal income tax benefit, amounted to $2.4 million as additional income tax expense during the three months ended June 30, 2013. In 2013, the FASB issued Accounting Standards Update 2013-11, which requires entities to present an unrecognized tax benefit as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward if such carryforward could be used to offset the unrecognized tax benefit upon settlement. The update is required to be applied prospectively for periods beginning after December 15, 2013, and early adoption was permitted. The Company elected not to adopt the change for 2013, but did adopt it for 2014 as required by the update. Had the Company applied the update at December 31, 2013, the effect would have been decreases in net operating deferred tax assets of $19.9 million for PNMR, $11.2 million for PNM, and $6.8 million for TNMP, along with the elimination of the corresponding assets and liabilities associated with unrecognized tax benefits. There was no impact to earning from adopting the update.

Income Taxes

On January 3, 2013, the American Taxpayer Relief Act of 2012, which extended fifty percent bonus depreciation, was signed into law. Due to provisions in the act, taxes payable to the State of New Mexico for 2013 were reduced, which resulted in an impairment of New Mexico wind energy production tax credits. In accordance with GAAP, PNMR was required to record this impairment, which after federal income tax benefit, amounted to $1.5 million as additional income tax expense during the three months ended March 31, 2013. This impairment is reflected in PNMR’s Corporate and Other segment.

On April 4, 2013, New Mexico House Bill 641 was signed into law. One of the provisions of the bill was to reduce the New Mexico corporate income tax rate from 7.6% to 5.9%. The rate reduction will be phased in from 2014 to 2018. In accordance with GAAP, PNMR and PNM adjusted accumulated deferred income taxes to reflect the tax rate at which the balances are expected to reverse during the period that includes the date of enactment, which was in three months ended June 30, 2013. At that time, the portion of the adjustment related to PNM’s regulated activities was recorded as a reduction in deferred tax liabilities, which was offset by an increase in a regulatory liability, on the assumption that PNM will be required to return the benefit to customers over time. The increase in the regulatory liability was $23.9 million. In addition, the portion of the adjustment that is not related to PNM’s regulated activities was recorded as a reduction in deferred tax assets and an increase in income tax expense of $1.2 million. Changes in the estimated timing of reversals of deferred tax assets and liabilities will result in refinements of the impacts of this change in tax rates being recorded periodically until 2018, when the rate reduction is fully phased in. In the three months ended March 31, 2014, PNM’s regulatory liability was reduced by $4.6 million, which increased deferred tax liabilities. Additionally, deferred tax assets not related to PNM’s regulatory activities were reduced by $0.2 million, which increased income tax expense.

In 2013, the future reduction in taxes payable to the State of New Mexico resulting from the rate reduction in House Bill 641 and revisions in estimates of future taxable income resulted in a further impairment of New Mexico wind energy production tax credits. In accordance with GAAP, PNMR was required to record this impairment, which after federal income tax benefit, amounted to $2.4 million as additional income tax expense during the three months ended June 30, 2013.

In 2013, the FASB issued Accounting Standards Update 2013-11, which requires entities to present an unrecognized tax benefit as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward if such carryforward could be used to offset the unrecognized tax benefit upon settlement. The update is required to be applied prospectively for periods beginning after December 15, 2013, and early adoption was permitted. The Company elected not to adopt the change for 2013, but did adopt it for 2014 as required by the update. Had the Company applied the update at December 31, 2013, the effect would have been decreases in net operating deferred tax assets of $19.9 million for PNMR, $11.2 million for PNM, and $6.8 million for TNMP, along with the elimination of the corresponding assets and liabilities associated with unrecognized tax benefits. There was no impact to earning from adopting the update.