Income Taxes

Income Tax Expense (Benefit)

The table below shows our consolidated income tax expense (benefit) and our effective tax rates for the periods indicated (in millions):



	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
Income tax expense (benefit)	$	(2	)	$	(4	)	$	—		$	17
Effective tax rate	(1		)%	(1		)%	—		%	20		%

Our income tax rates do not bear a customary relationship to statutory income tax rates primarily as a result of the effect of our NOLs, changes in unrecognized tax benefits and valuation allowances. For the three and nine months ended September 30, 2017 and 2016, our income tax expense (benefit) is largely comprised of discrete tax items and estimated state and foreign income taxes in jurisdictions where we do not have NOLs or valuation allowances. During the nine months ended September 30, 2017, we recorded an income tax benefit of $17 million associated with a favorable adjustment to our reserve for uncertain tax positions.

NOL Carryforwards — As of December 31, 2016, our NOL carryforwards consist primarily of federal NOL carryforwards of approximately $6.7 billion, which expire between 2024 and 2033, and NOL carryforwards in 21 states and the District of Columbia totaling approximately $3.7 billion, which expire between 2017 and 2036, substantially all of which are offset with a full valuation allowance. Certain of the state NOL carryforwards may be subject to limitations on their annual usage. Under federal and state income tax law, our NOL carryforwards can be utilized to reduce future taxable income subject to certain new limitations including if we were to undergo an ownership change as defined by Section 382 of the Internal Revenue Code and similar state provisions.

We also have approximately $647 million in foreign NOLs, which expire between 2025 and 2033, and the associated deferred tax asset of approximately $161 million is partially offset by a valuation allowance of $101 million. Under Canadian income tax law, our NOL carryforwards can be utilized to reduce future taxable income subject to certain limitations including new applicable limitations resulting from an ownership change which will result in an increase in the valuation allowance and a related charge to deferred tax expense.

Income Tax Audits — We remain subject to periodic audits and reviews by taxing authorities; however, we do not expect these audits will have a material effect on our tax provision. Any NOLs we claim in future years to reduce taxable income could be subject to IRS examination regardless of when the NOLs were generated. Any adjustment of state or federal returns could result in a reduction of deferred tax assets rather than a cash payment of income taxes in tax jurisdictions where we have NOLs. We are currently under U.S. federal income tax examination for the year ended December 31, 2015 and various state income tax audits for various periods. Our Canadian subsidiaries are currently under examination by the Canada Revenue Agency for the years ended December 31, 2013 through 2016.

Valuation Allowance — U.S. GAAP requires that we consider all available evidence, both positive and negative, and tax planning strategies to determine whether, based on the weight of that evidence, a valuation allowance is needed to reduce the value of deferred tax assets. Future realization of the tax benefit of an existing deductible temporary difference or carryforward ultimately depends on the existence of sufficient taxable income of the appropriate character within the carryback or carryforward periods available under the tax law. Due to our history of losses, we were unable to assume future profits; however, we are able to consider available tax planning strategies.

Unrecognized Tax Benefits — At September 30, 2017, we had unrecognized tax benefits of $48 million. If recognized, $10 million of our unrecognized tax benefits could affect the annual effective tax rate and $38 million, related to deferred tax assets, could be offset against the recorded valuation allowance resulting in no effect on our effective tax rate. We had accrued interest and penalties of $4 million for income tax matters at September 30, 2017. We recognize interest and penalties related to unrecognized tax benefits in income tax expense (benefit) on our Consolidated Condensed Statements of Operations. We believe that it is reasonably possible that a decrease within the range of nil and $7 million in unrecognized tax benefits could occur within the next twelve months primarily related to foreign tax issues.