Income Taxes Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Components of Income Tax Expense (Benefit)

The components of the income tax provision (benefit) for each of the periods presented below are as follows:



	Years Ended December 31,
	2017			2016			2015
	($ in millions)
Current
Federal	$	(14	)	$	(14	)	$	—
State	5			(5		)	(36		)
Current Income Taxes	(9		)	(19		)	(36		)
Deferred
Federal	13			(147		)	(4,385		)
State	(2		)	(24		)	(42		)
Deferred Income Taxes	11			(171		)	(4,427		)
Total	$	2		$	(190	)	$	(4,463	)

Schedule of Effective Income Tax Rate Reconciliation

The effective income tax expense (benefit) differed from the computed "expected" federal income tax expense on earnings before income taxes for the following reasons:



	Years Ended December 31,
	2017			2016			2015
	($ in millions)
Income tax expense (benefit) at the federal statutory rate (35%)	$	333		$	(1,606	)	$	(6,684	)
State income taxes (net of federal income tax benefit)	66			(30		)	(406		)
Remeasurement of deferred tax assets and liabilities	1,266			—			—
Change in valuation allowance	(1,676		)	1,423			2,727
Other	13			23			(100		)
Total	$	2		$	(190	)	$	(4,463	)

Schedule of Deferred Tax Assets and Liabilities

The tax-effected temporary differences, tax credits and net operating loss carryforwards that comprise our deferred taxes are as follows:



	Years Ended December 31,
	2017			2016
	($ in millions)
Deferred tax liabilities:
Volumetric production payments	$	(129	)	$	(223	)
Other	(20		)	(62		)
Deferred tax liabilities	(149		)	(285		)

Deferred tax assets:
Property, plant and equipment	1			593
Net operating loss carryforwards	2,248			2,587
Carrying value of debt	161			539
Asset retirement obligations	42			98
Investments	161			275
Derivative instruments	17			161
Accrued liabilities	125			319
Other	71			118
Deferred tax assets	2,826			4,690
Valuation allowance	(2,674		)	(4,389		)
Net deferred tax assets	152			301
Net deferred tax assets	$	3		$	16

Schedule of Unrecognized Tax Benefits Roll Forward

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



	2017			2016			2015
	($ in millions)
Unrecognized tax benefits at beginning of period	$	202		$	280		$	303
Additions based on tax positions related to the current year	—			—			27
Additions to tax positions of prior years	4			33			—
Settlements	(100		)	(111		)	—
Reductions to tax positions of prior years	—			—			(50		)
Unrecognized tax benefits at end of period	$	106		$	202		$	280