Details of income tax provisions and deferred income taxes from continuing operations are provided in the following tables. The components of income tax provisions and benefits were as follows:



	Year Ended December 31,
	2015			2014			2013
	(in millions)
Federal income tax provision (benefit)
Current	$	(112.3	)	$	(324.0	)	$	(92.2	)
Deferred	34.5			110.3			152.3
State income tax provision (benefit)
Current	(6.6		)	(15.5		)	(1.4		)
Deferred	(9.2		)	(3.3		)	1.4
Total income tax provision (benefit)	$	(93.6	)	$	(232.5	)	$	60.1

The difference between the statutory federal income tax rate and the Company's effective income tax rate is explained as follows:



	Year Ended December 31,
	2015		2014		2013
Federal income taxes statutory rate	35.0	%	35.0	%	35.0	%
Increase (decrease) in rate as a result of:
State income taxes, net of federal income tax benefit	4.2	%	(1.5	)%	(5.0	)%
State rate change	—	%	3.4	%	—	%
Penalties	(0.3	)%	—	%	0.4	%
Return to provision adjustment	(0.3	)%	(0.4	)%	5.0	%
Book impairment of goodwill	—	%	—	%	18.6	%
Other	(0.1	)%	(0.3	)%	(0.4	)%
Effective income tax rate	38.5	%	36.2	%	53.6	%

Significant components of the Company's deferred income taxes were as follows:



	December 31,
	2015		2014
	(in millions)
Deferred tax liabilities
Property, plant and equipment	$	1,531.0	$	1,402.9
Commodity price and interest rate derivatives	60.4		127.7
Total deferred tax liabilities	1,591.4		1,530.6
Deferred tax assets
Net operating loss and tax credit carryforwards	51.9		11.7
Employee benefits and compensation costs	43.6		43.0
Bonus and vacation accrual	7.0		16.3
Other	9.1		12.4
Total deferred tax assets	111.6		83.4
Net deferred income tax liability	$	1,479.8	$	1,447.2
Balance sheet classification
Deferred income tax asset - current	$	—	$	—
Deferred income tax liability - current	—		84.5
Deferred income tax liability - non-current	1,479.8		1,362.7
Net deferred income tax liability	$	1,479.8	$	1,447.2

The amounts and expiration dates of net operating loss and tax credit carryforwards at December 31, 2015 are as follows:



	Expiration Dates	Amounts
		(in millions)
State net operating loss and tax credit carryforwards	2015-2033	$	40.5
State net operating loss valuation allowance		(20.3		)
U.S. alternative minimum tax credit	Indefinite	—
Total		$	20.2

The valuation allowance of $20.3 million was established in 2014 against the available state net operating loss and is related primarily to losses incurred in Oklahoma. Due to the 2014 Midcontinent property sales in which the Company sold its interests in most of its properties in Oklahoma, the Company does not forecast sufficient taxable income to utilize the net operating loss in Oklahoma.

Unrecognized Tax Benefit

As of December 31, 2015, QEP had $15.6 million of unrecognized tax benefits related to uncertain tax positions for asset sales that occurred in 2014, which were recorded within "Other long-term liabilities" on the Consolidated Balance Sheet. At December 31, 2014, no uncertain tax positions had been recorded. The uncertain tax positions the Company reported during the year ended December 31, 2015, were expensed during the year ended December 31, 2014. The benefits of uncertain tax positions taken or expected to be taken on income tax returns is recognized in the consolidated financial statements at the largest amount that is more likely than not to be sustained upon examination by the relevant taxing authorities. Our policy is to recognize any interest expense related to uncertain tax positions in "Interest expense" on the Consolidated Statement of Operations and to recognize any penalties related to uncertain tax positions in "General and administrative" expense on the Consolidated Statements of Operations. During the year ended December 31, 2015, the Company incurred $0.5 million of interest expense and $2.2 million of penalties related to uncertain tax positions.

The following is a reconciliation of our beginning and ending amounts of unrecognized tax benefits for the year ended December 31, 2015:



	2015
	(in millions)
Balance as of January 1,	$	—
Additions for tax positions taken during the current period	15.6
Balance as of December 31,	$	15.6

As of December 31, 2015, QEP had approximately $15.6 million of unrecognized tax benefit that would impact our effective tax rate if recognized.