Quarterly report pursuant to Section 13 or 15(d)


3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]  
Income Taxes
Our 2018 estimated annual effective tax rate before discrete items is approximately 0.1%. The annual effective tax rate differs from the U.S. statutory rate of 21% primarily due to the deductions for percentage depletion in excess of cost depletion related to U.S. operations and the reversal of valuation allowance from operations in the current year. The 2017 estimated annual effective tax rate before discrete items at March 31, 2017 was 5.4%.
For the three months ended March 31, 2018 and 2017, we recorded discrete items that resulted in an income tax expense of $15.7 million and a benefit of $0.1 million, respectively. The current year items relate primarily to a $14.5 million reduction of the refundable AMT credit recorded in Income tax receivable in our Statements of Unaudited Condensed Consolidated Financial Position based on the sequestration guidance issued by the Internal Revenue Service during the period ended March 31, 2018. This $14.5 million current year expense is a reduction of an asset and will not result in a cash tax outlay.