Income Taxes

The provision for income taxes is comprised of the following:



	Years Ended December 31,
	2015			2014			2013
	(In thousands)
Current
Federal	$	480,446		$	294,509		$	270,024
State	71,750			40,325			7,148
Deferred
Federal	(127,714		)	(168,756		)	94,896
State	(18,422		)	(24,906		)	19,508
	$	406,060		$	141,172		$	391,576

The statutory federal income tax rate applied to pre-tax book income reconciles to income tax expense as follows:



	Years Ended December 31,
	2015			2014			2013
	(In thousands)
Tax computed at statutory rate	$	422,999		$	163,625		$	405,790
State income taxes, net of federal tax benefit	40,385			13,641			21,363
Domestic production activities deduction	(35,200		)	(20,998		)	(22,101		)
Noncontrolling interest in net income	(24,155		)	(17,431		)	(12,378		)
Uncertain tax positions	—			—			(193		)
Other	2,031			2,335			(905		)
	$	406,060		$	141,172		$	391,576

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Our deferred income tax assets and liabilities as of December 31, 2015 and 2014 are as follows:



	December 31, 2015
	Assets		Liabilities			Total
	(In thousands)
Deferred income taxes
Properties, plants and equipment (due primarily to tax in excess of book depreciation)	$	—	$	(648,542	)	$	(648,542	)
Accrued employee benefits	22,355		—			22,355
Accrued post-retirement benefits	11,518		—			11,518
Accrued environmental costs	42,517		—			42,517
Hedging instruments	21,815		—			21,815
Inventory differences	175,614		—			175,614
Deferred turnaround costs	—		(104,944		)	(104,944		)
Net operating loss and tax credit carryforwards	8,033		—			8,033
Investment in HEP	—		(23,429		)	(23,429		)
Other	—		(2,843		)	(2,843		)
Total	$	281,852	$	(779,758	)	$	(497,906	)



	December 31, 2014
	Assets		Liabilities			Total
	(In thousands)
Deferred income taxes
Properties, plants and equipment (due primarily to tax in excess of book depreciation)	$	—	$	(581,017	)	$	(581,017	)
Accrued employee benefits	22,973		—			22,973
Accrued post-retirement benefits	11,504		—			11,504
Accrued environmental costs	30,744		—			30,744
Hedging instruments	—		(11,601		)	(11,601		)
Inventory differences	—		(7,376		)	(7,376		)
Deferred turnaround costs	—		(110,827		)	(110,827		)
Net operating loss and tax credit carryforwards	10,119		—			10,119
Investment in HEP	—		(25,244		)	(25,244		)
Other	—		(3,554		)	(3,554		)
Total	$	75,340	$	(739,619	)	$	(664,279	)

At December 31, 2015, we had a Kansas income tax credit of $6.6 million that is scheduled to be utilized in 2016 through 2019. This amount is reflected in non-current deferred tax assets.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:



	Years Ended December 31,
	2014			2013
	(In thousands)
Balance at January 1	$	9,006		$	12,641
Additions for tax positions of prior years	—			25,728
Reductions for tax positions of prior years	—			(5,092		)
Settlements	(9,006		)	(24,271		)
Balance at December 31	$	—		$	9,006

We had no unrecognized tax benefits at December 31, 2015 and 2014. We recognize interest and penalties relating to liabilities for unrecognized tax benefits as an element of tax expense.

We are subject to U.S. federal income tax, Oklahoma, Kansas, New Mexico, Iowa, Arizona, Utah, Colorado and Nebraska income tax and to income tax of multiple other state jurisdictions. We have substantially concluded all state and local income tax matters for tax years through 2012 and have materially concluded all U.S. federal income tax matters for tax years through December 31, 2013.