Income Taxes

The Company's income tax benefit (provision) consisted of the following for the three months ended March 31, 2018 and 2017:



	Three Months Ended March 31,
	2018			2017
	(in millions)
Deferred tax benefit (provision)	$	(50	)	$	31

For the three months ended March 31, 2018, the Company's effective tax rate, excluding income attributable to noncontrolling interests, was 22 percent, as compared to an effective rate of 42 percent for the same period in 2017. The U.S. statutory rate for the three months ended March 31, 2018 was 21 percent, reflecting the reduction in the federal corporate income tax rate from 35 percent to 21 percent beginning in 2018 as a result of the Tax Cuts and Jobs Act that was enacted in December 2017. The Company's effective tax rate for the three months ended March 31, 2017 differs from the U.S. statutory rate in effect during 2017 of 35 percent primarily due to recognizing excess tax benefits of $8 million associated with the adoption of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting," which requires excess tax benefits or deficiencies associated with the vesting of long-term incentive awards to be recorded as income tax expense or benefit in the statement of operations rather than as an adjustment to additional paid-in capital in the balance sheet.

The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by the taxing authorities based upon the technical merits of the position. As of March 31, 2018 and December 31, 2017, the Company had cumulative unrecognized tax benefits of $127 million and $124 million, respectively, resulting from research and experimental expenditures related to horizontal drilling and completions innovations. If all or a portion of the unrecognized tax benefit is sustained upon examination by the taxing authorities, the tax benefit will be recognized as a reduction to the Company's deferred tax liability and will affect the Company's effective tax rate in the period it is recognized. The Company expects to substantially resolve the uncertainties associated with the unrecognized tax benefit by December 2018.

The Company files income tax returns in the U.S. federal and various state and foreign jurisdictions. The Internal Revenue Service has closed examinations of the 2012 and prior tax years and, with few exceptions, the Company believes that it is no longer subject to examinations by state and foreign tax authorities for years before 2012. As of March 31, 2018, no adjustments had been proposed in any jurisdiction that would have a significant effect on the Company's liquidity, future results of operations or financial position.