Income Taxes	3 Months Ended
Mar. 31, 2018
Income Taxes
Income Taxes	5. Income Taxes Our effective income tax rate for the three months ended March 31, 2018 and 2017 was 22.7% and 31.7%, respectively. We evaluate our effective income tax rate at each interim period and adjust it as facts and circumstances warrant. The decrease in the effective income tax rate for the three months ended March 31, 2018, compared with the prior year period, was primarily due to the enactment of tax reform, as discussed below. The difference between federal income taxes computed at the federal statutory rate and reported income taxes for the three months ended March 31, 2018 was primarily due to the unfavorable impact of state and local income taxes offset, in part, by the favorable impact of federal tax credits and excess tax benefits related to equity-based compensation. The difference between federal income taxes computed at the federal statutory rate and reported income taxes for the three months ended March 31, 2017 was primarily due to the favorable impact of excess tax benefits related to equity-based compensation and federal tax credits offset, in part, by the unfavorable impact of state and local income taxes and the tax implications of impairments. Enactment of Tax Reform – The Act was signed into law on December 22, 2017. The most significant impacts of the Act to the Company include a reduction in the federal corporate income tax rate from 35% to 21%, effective January 1, 2018, and a one-time, mandatory transition tax on deemed repatriation of previously tax-deferred and unremitted foreign earnings. In accordance with ASU 2018-05 and SAB 118, the Company recognized the provisional tax impacts related to the re-measurement of our deferred income tax assets and liabilities and the one-time, mandatory transition tax on deemed repatriation during the year ended December 31, 2017. As of March 31, 2018, we have not made any additional measurement-period adjustments related to these items. Such adjustments may be necessary in future periods due to, among other things, the significant complexity of the Act and anticipated additional regulatory guidance that may be issued by the Internal Revenue Service (“IRS”), changes in analysis, interpretations and assumptions the Company has made and actions the Company may take as a result of the Act. We are continuing to gather information to assess the application of the Act and expect to complete our analysis with the filing of our 2017 income tax returns during the third quarter of 2018. Equity-Based Compensation — During the three months ended March 31, 2018 and 2017, we recognized a reduction in our income tax expense of $11 million and $32 million, respectively, for excess tax benefits related to the vesting or exercise of equity-based compensation awards. Investments Qualifying for Federal Tax Credits — We have significant financial interests in entities established to invest in and manage low-income housing properties and a refined coal facility. We support the operations of these entities in exchange for a pro-rata share of the tax credits they generate. The low-income housing investments and the coal facility’s refinement processes qualify for federal tax credits that we expect to realize through 2020 under Section 42 and through 2019 under Section 45, respectively, of the Internal Revenue Code. We account for our investments in these entities using the equity method of accounting, recognizing our share of each entity’s results of operations and other reductions in the value of our investments in equity in net losses of unconsolidated entities, within our Condensed Consolidated Statements of Operations. During the three months ended March 31, 2018 and 2017, we recognized $6 million of net losses and a reduction in our income tax expense of $10 million and $11 million, respectively, primarily because of tax credits realized from these investments. Interest expense associated with our investment in low-income housing properties was not material for the periods presented. See Note 13 for additional information related to these unconsolidated variable interest entities.

5. Income Taxes

Our effective income tax rate for the three months ended March 31, 2018 and 2017 was 22.7% and 31.7%, respectively. We evaluate our effective income tax rate at each interim period and adjust it as facts and circumstances warrant. The decrease in the effective income tax rate for the three months ended March 31, 2018, compared with the prior year period, was primarily due to the enactment of tax reform, as discussed below.

The difference between federal income taxes computed at the federal statutory rate and reported income taxes for the three months ended March 31, 2018 was primarily due to the unfavorable impact of state and local income taxes offset, in part, by the favorable impact of federal tax credits and excess tax benefits related to equity-based compensation. The difference between federal income taxes computed at the federal statutory rate and reported income taxes for the three months ended March 31, 2017 was primarily due to the favorable impact of excess tax benefits related to equity-based compensation and federal tax credits offset, in part, by the unfavorable impact of state and local income taxes and the tax implications of impairments.

Enactment of Tax Reform – The Act was signed into law on December 22, 2017. The most significant impacts of the Act to the Company include a reduction in the federal corporate income tax rate from 35% to 21%, effective January 1, 2018, and a one-time, mandatory transition tax on deemed repatriation of previously tax-deferred and unremitted foreign earnings.

In accordance with ASU 2018-05 and SAB 118, the Company recognized the provisional tax impacts related to the re-measurement of our deferred income tax assets and liabilities and the one-time, mandatory transition tax on deemed repatriation during the year ended December 31, 2017. As of March 31, 2018, we have not made any additional measurement-period adjustments related to these items. Such adjustments may be necessary in future periods due to, among other things, the significant complexity of the Act and anticipated additional regulatory guidance that may be issued by the Internal Revenue Service (“IRS”), changes in analysis, interpretations and assumptions the Company has made and actions the Company may take as a result of the Act. We are continuing to gather information to assess the application of the Act and expect to complete our analysis with the filing of our 2017 income tax returns during the third quarter of 2018.

Equity-Based Compensation — During the three months ended March 31, 2018 and 2017, we recognized a reduction in our income tax expense of $11 million and $32 million, respectively, for excess tax benefits related to the vesting or exercise of equity-based compensation awards.

Investments Qualifying for Federal Tax Credits — We have significant financial interests in entities established to invest in and manage low-income housing properties and a refined coal facility. We support the operations of these entities in exchange for a pro-rata share of the tax credits they generate. The low-income housing investments and the coal facility’s refinement processes qualify for federal tax credits that we expect to realize through 2020 under Section 42 and through 2019 under Section 45, respectively, of the Internal Revenue Code.

We account for our investments in these entities using the equity method of accounting, recognizing our share of each entity’s results of operations and other reductions in the value of our investments in equity in net losses of unconsolidated entities, within our Condensed Consolidated Statements of Operations. During the three months ended March 31, 2018 and 2017, we recognized $6 million of net losses and a reduction in our income tax expense of $10 million and $11 million, respectively, primarily because of tax credits realized from these investments. Interest expense associated with our investment in low-income housing properties was not material for the periods presented. See Note 13 for additional information related to these unconsolidated variable interest entities.