Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Components of income before income taxes

The components of income before income taxes from continuing operations for each of the years ended December 31 were as follows:



	2017			2016			2015
				(In thousands)
United States	$	350,064		$	326,252		$	248,379
Foreign	(37		)	(24		)	(1,326		)
Income before income taxes from continuing operations	$	350,027		$	326,228		$	247,053

Income tax expense

Income tax expense from continuing operations for the years ended December 31 was as follows:



	2017			2016			2015
				(In thousands)
Current:
Federal	$	74,272		$	81,989		$	85,897
State	16,192			13,190			10,093
Foreign	—			2			30
	90,464			95,181			96,020
Deferred:
Income taxes:
Federal	(24,497		)	(2,102		)	(19,632		)
State	(864		)	1,184			(5,304		)
Investment tax credit - net	(62		)	(1,131		)	(420		)
	(25,423		)	(2,049		)	(25,356		)
Total income tax expense	$	65,041		$	93,132		$	70,664

Deferred tax assets and deferred tax liabilities

Components of deferred tax assets and deferred tax liabilities at December 31 were as follows:



	2017		2016
	(In thousands)
Deferred tax assets:
Postretirement	$	55,736	$	87,872
Compensation-related	16,298		44,995
Alternative minimum tax credit carryforward	37,683		29,338
Federal renewable energy credit	19,367		16,944
Customer advances	8,712		13,524
Legal and environmental contingencies	7,363		9,895
Asset retirement obligations	6,380		8,867
Other	35,738		46,957
Total deferred tax assets	187,277		258,392
Deferred tax liabilities:
Depreciation and basis differences on property, plant and equipment	429,577		774,838
Postretirement	43,505		70,670
Intangible asset amortization	16,979		26,413
Other	32,591		45,580
Total deferred tax liabilities	522,652		917,501
Valuation allowance	11,896		9,117
Net deferred income tax liability	$	347,271	$	668,226

Schedule of change in net deferred income tax liability reconciliation

The following table reconciles the change in the net deferred income tax liability from December 31, 2016, to December 31, 2017, to deferred income tax benefit:



	2017
(In thousands)
Change in net deferred income tax liability from the preceding table	$	(320,955	)
Deferred taxes associated with other comprehensive loss	1,182
Deferred taxes associated with TCJA enactment for regulated activities	285,520
Other	8,830
Deferred income tax benefit for the period	$	(25,423	)

Reconciliation of income tax expense (benefit) at statutory federal rate versus actual rate

Total income tax expense differs from the amount computed by applying the statutory federal income tax rate to income before taxes. The reasons for this difference were as follows:



Years ended December 31,	2017					2016					2015
	Amount			%		Amount			%		Amount			%
	(Dollars in thousands)
Computed tax at federal statutory rate	$	122,509		35.0		$	114,179		35.0		$	86,468		35.0
Increases (reductions) resulting from:
State income taxes, net of federal income tax	10,724			3.1		9,027			2.8		8,208			3.3
Federal renewable energy credit	(13,958		)	(4.0	)	(13,544		)	(4.2	)	(3,400		)	(1.4	)
Tax compliance and uncertain tax positions	(643		)	(.2	)	(3,028		)	(.9	)	(2,607		)	(1.0	)
Domestic production deduction	(6,849		)	(2.0	)	(6,251		)	(1.9	)	(6,842		)	(2.8	)
TCJA revaluation	(47,242		)	(13.5	)	—			—		—			—
TCJA revaluation related to accumulated other comprehensive loss balance	7,735			2.2		—			—		—			—
Other	(7,235		)	(2.0	)	(7,251		)	(2.3	)	(11,163		)	(4.5	)
Total income tax expense	$	65,041		18.6		$	93,132		28.5		$	70,664		28.6