Income Taxes (Tables)

12 Months Ended

Dec. 31, 2012

Table Text Block Supplement [Abstract]

Income Tax Provision (Benefit) [Table Text Block]

Our income tax provision (benefit) is as follows:

	Year Ended December 31,
In thousands	2012		2011			2010
Current income tax expense (benefit)
Federal	$	57,720	$	(12,552	)	$	15,683
State	18,034		20,801			17,511
Total current income tax expense	75,754		8,249			33,194
Deferred income tax expense
Federal	239,862		329,715			143,381
State	15,881		12,748			16,968
Total deferred income tax expense	255,743		342,463			160,349
Total income tax expense	$	331,497	$	350,712		$	193,543

Deferred Tax Assets And Liabilities [Table Text Block]

Significant components of our deferred tax assets and liabilities as of December 31, 2012 and 2011 are as follows:

	December 31,
In thousands	2012			2011
Deferred tax assets:
Loss carryforwards – federal	$	—		$	13,970
Loss carryforwards – state	35,007			41,960
Tax credit carryover	34,837			34,829
Derivative contracts	7,252			3,551
Enhanced oil recovery credit carryforwards	17,346			53,381
Stock based compensation	28,387			32,566
Other	37,226			35,279
Total deferred tax assets	160,055			215,536
Deferred tax liabilities:
Property and equipment	(2,277,388		)	(2,078,143		)
Other	(6,963		)	(5,813		)
Total deferred tax liabilities	(2,284,351		)	(2,083,956		)
Total net deferred tax liability	$	(2,124,296	)	$	(1,868,420	)

Income Tax Provision (Benefit) Continuing Operations Income Tax Reconciliation [Table Text Block]

Our reconciliation of income tax expense computed by applying the U.S. federal statutory rate and the reported effective tax rate on income from continuing operations is as follows:

	Year Ended December 31,
In thousands	2012			2011			2010
Income tax provision calculated using the federal statutory income tax rate	$	299,900		$	323,416		$	167,674
State income taxes, net of federal income tax benefit	30,955			29,555			13,087
Effect of statutory rate change	(429		)	(578		)	11,502
Other	1,071			(1,681		)	1,280
Total income tax expense	$	331,497		$	350,712		$	193,543