Income Taxes

The differences that caused our effective income tax rates to differ from the 35% U.S. federal statutory rate for income taxes were as follows:



	Nine Months Ended December 31,
	2016			2015
	(in millions)
Income tax benefit at the federal statutory rate	$	223		$	460
Effect of:
State income taxes, net of federal income tax effect	8			33
State law changes, net of federal income tax effect	3			23
Increase deferred tax liability on FCC licenses	(46		)	—
Tax benefit from organizational restructuring	42			—
Change in federal and state valuation allowance	(522		)	(647		)
Other, net	6			5
Income tax expense	$	(286	)	$	(126	)
Effective income tax rate	(44.9		)%	(9.6		)%

The realization of deferred tax assets, including net operating loss carryforwards, is dependent on the generation of future taxable income sufficient to realize the tax deductions, carryforwards and credits. However, our history of annual losses reduces our ability to rely on expectations of future income in evaluating the ability to realize our deferred tax assets. Valuation allowances on deferred tax assets are recognized if it is determined that it is more likely than not that the asset will not be realized. As a result, the Company recognized income tax expense to increase the valuation allowance by $522 million and $647 million during the nine-month periods ended December 31, 2016 and 2015, respectively, on deferred tax assets primarily related to losses incurred during the period that were not currently realizable and expenses recorded during the period that were not currently deductible for income tax purposes. We do not expect to record significant tax benefits on future net operating losses until our circumstances justify the recognition of such benefits.

We believe it is more likely than not that our remaining deferred income tax assets, net of the valuation allowance, will be realized based on current income tax laws and expectations of future taxable income stemming from the reversal of existing deferred tax liabilities. Uncertainties surrounding income tax law changes, shifts in operations between state taxing jurisdictions and future operating income levels may, however, affect the ultimate realization of all or some of these deferred income tax assets.

Income tax expense of $286 million for the nine-month period ended December 31, 2016 was primarily attributable to taxable temporary differences from the tax amortization of FCC licenses and tax expense on pre-tax gains from spectrum license exchanges during the period, partially offset by tax benefits from the reversal of certain state income tax valuation allowance on deferred tax assets. As a result of organizational restructuring, which drove a sustained increase in the profitability of specific legal entities, we revised our estimate regarding the realizability of the involved entities’ deferred state tax assets and recorded a state tax benefit of $42 million. Additionally, in conjunction with the Spectrum Financing and resulting change in state taxability footprint, we recognized tax expense of $46 million to increase the deferred tax liability for the temporary differences between the carrying amounts of our FCC licenses for financial statement purposes and their tax bases. Income tax expense of $126 million for the nine-month period ended December 31, 2015 was primarily attributable to taxable temporary differences from the tax amortization of FCC licenses, partially offset by tax benefits recorded from changes in state income tax laws enacted during the period. FCC licenses are amortized over 15 years for income tax purposes but, because these licenses have an indefinite life, they are not amortized for financial statement reporting purposes. These temporary differences cannot be scheduled to reverse during the loss carryforward period against our deferred tax assets. As a result, a valuation allowance is recorded against our loss carryforward and other excess deferred tax assets resulting in a net deferred tax expense.

As of December 31, 2016 and March 31, 2016, we maintained unrecognized tax benefits of $176 million and $166 million, respectively. Cash paid for income taxes, net, was $34 million for each of the nine-month periods ended December 31, 2016 and 2015.

In March 2016, the FASB issued authoritative guidance on Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting which, in part, eliminates the additional paid-in capital pools and requires excess tax benefits and tax deficiencies to be recorded in the income statement when the awards vest or are settled. The company has elected to early adopt this guidance effective April 1, 2016. The early adoption of this guidance did not have a material effect on our consolidated financial statements.