Income Taxes (Tables)

9 Months Ended

Dec. 31, 2017

Factors Causing Variation in Effective Tax Rate From US Federal Statutory Rate

The differences that caused our effective income tax rates to differ from the 31.5% and 35% U.S. federal statutory rate for income taxes for the nine-month periods ended December 31, 2017 and 2016, respectively, were as follows:



	Nine Months Ended December 31,
	2017			2016
	(in millions)
Income tax (expense) benefit at the federal statutory rate	$	(205	)	$	223
Effect of:
State income taxes, net of federal income tax effect	(57		)	8
State law changes, net of federal income tax effect	(28		)	3
Increase deferred tax liability on FCC licenses	—			(46		)
Increase deferred tax liability for business activity changes	(69		)	—
Credit for increasing research activities	11			—
Tax benefit from organizational restructuring	—			42
Change in federal and state valuation allowance	(64		)	(522		)
Increase in liability for unrecognized tax benefits	(20		)	—
Tax benefit from the Tax Act	7,090			—
Other, net	4			6
Income tax benefit (expense)	$	6,662		$	(286	)
Effective income tax rate	(1,021.8		)%	(44.9		)%

Schedule of Deferred Tax Assets and Liabilities

The sources of the differences that gave rise to the deferred tax assets and liabilities as of December 31, 2017 and March 31, 2017, along with the income tax effect of each, were as follows:



	December 31, 2017			March 31, 2017
	(in millions)
Deferred tax assets
Net operating loss carryforwards	$	4,169		$	6,812
Tax credit carryforwards	365			340
Capital loss carryforwards	—			1
Property, plant and equipment	1,997			2,192
Debt obligations	83			205
Deferred rent	237			402
Pension and other postretirement benefits	211			332
Accruals and other liabilities	907			1,454
	7,969			11,738
Valuation allowance	(5,212		)	(10,477		)
	2,757			1,261
Deferred tax liabilities
FCC licenses	8,793			12,876
Trademarks	1,122			1,712
Intangibles	340			771
Other	211			318
	10,466			15,677

Long-term deferred tax liability	$	7,709		$	14,416