Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes For interim tax reporting, the Company estimates its annual effective tax rate and applies it to year-to-date ordinary income. Jurisdictions where no tax benefit can be recognized due to a valuation allowance are excluded from the estimated annual effective tax rate. The effect of including these jurisdictions on the quarterly effective rate calculation could result in a higher or lower effective tax rate during a quarter due to the mix and timing of actual earnings versus annual projections. The tax effects of certain items, including changes in judgment about valuation allowances and effects of changes in tax laws or rates, are excluded from the estimated annual effective tax rate calculation and recognized in the interim period in which they occur. The Company considers both positive and negative evidence and evaluates its deferred tax assets quarterly to determine if valuation allowances are required or should be adjusted. This assessment considers, among other matters, the nature, frequency and amount of recent losses, the duration of statutory carryforward periods, reversals of existing taxable temporary differences, and tax planning strategies. In making such judgments, significant weight is given to evidence that can be objectively verified. For the three months ended March 31, 2021, the Company recorded an income tax expense of $47 million on income from continuing operations before income taxes of $134 million. This compares to an income tax benefit of $94 million on loss from continuing operations before income taxes of $920 million in the three months ended March 31, 2020. Income tax expense for the three months ended March 31, 2021 differs from the U.S. statutory rate due primarily to pre-tax income taxed at rates higher than the U.S. statutory rate and pre-tax losses with no tax benefits. Income tax expense for the three months ended March 31, 2020 differs from the U.S. statutory rate due primarily to $105 million of tax benefit recognized relating to the asset impairment charges of $854 million, pre-tax income taxed at rates higher than the U.S. statutory rate, and pre-tax losses with no tax benefits.The Company received notification in the first quarter of 2021 that its U.S. tax refund claim is approved and the tax years through 2016 are now effectively settled. The Company believes it is reasonably possible up to $44 million in unrecognized tax benefits related to the expiration of statute of limitations and the conclusion of income tax examinations may be recognized within the next twelve months. The Company has released $54 million of unrecognized tax benefits with a corresponding adjustment of $54 million to the Company’s valuation allowance as a result of the conclusion of income tax examinations in the first quarter of 2021.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.