Disclosures About Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Assets And Liabilities That Are Measured At Fair Value On A Recurring Basis

The following tables present the Company's assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2013 and 2012 for each of the fair value hierarchy levels:

	Fair Value Measurements at the End of the Reporting Period Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at December 31, 2013
	(in thousands)
Assets:
Trading securities	$	136	$	146	$	—	$	282
Commodity derivatives	—		156,561		—		156,561
Interest rate derivatives	—		9,530		—		9,530
Deferred compensation plan assets	63,971		—		—		63,971
Total assets	64,107		166,237		—		230,344
Liabilities:
Commodity derivatives	—		11,626		—		11,626
Interest rate derivatives	—		9,933		—		9,933
Total liabilities	—		21,559		—		21,559
Total recurring fair value measurements	$	64,107	$	144,678	$	—	$	208,785

	Fair Value Measurements at the End of the Reporting Period Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at December 31, 2012
	(in thousands)
Assets:
Trading securities	$	124	$	154	$	—	$	278
Commodity derivatives	—		334,376		—		334,376
Deferred compensation plan assets	49,685		—		—		49,685
Total assets	49,809		334,530		—		384,339
Liabilities:
Commodity derivatives	—		15,999		—		15,999
Interest rate derivatives	—		9,724		—		9,724
Total liabilities	—		25,723		—		25,723
Total recurring fair value measurements	$	49,809	$	308,807	$	—	$	358,616

Fair Value Measurements, Nonrecurring [Table Text Block]

The following table presents the fair value and fair value adjustments (in millions) for the Company's 2013, 2012 and 2011 proved property impairments, as well as the average oil price per barrel ("BBL") and gas price per British thermal unit ("MMBTU") utilized in respective Management's Price Outlooks:

	Year ended	Fair		Fair Value			Management's Price Outlooks
	December 31,	Value		Adjustment			Oil		Gas
Edwards Trend/Austin Chalk	2011	$	189.9	$	(354.4	)	$	92.69	$	5.14
Barnett Shale	2012	$	184.8	$	(532.6	)	$	87.09	$	4.78
Raton	2013	$	533.6	$	(1,495.2	)	$	80.40	$	4.43

Fair Value of Assets Classified as Held for Sale [Table Text Block]

The following table presents the estimated fair value less costs to sell and fair value adjustments for the Company's assets classified as held for sale as of December 31, 2013:

	Estimated Fair Value Less Costs to Sell		Fair Value Adjustment
	(in millions)
Discontinued operations held for sale - Alaska	$	350.6	$	(539.8	)
Discontinued operations held for sale - Barnett Shale field	$	180.4	$	(189.5	)
Other long-lived assets held for sale - Sendero	$	31.4	$	(25.5	)

Fair Value Measurements Not Carried At Fair Value

Carrying values and fair values of financial instruments that are not carried at fair value in the consolidated balance sheet as of December 31, 2013 and 2012 are as follows:

	December 31, 2013				December 31, 2012
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(in thousands)
Long-term debt	$	2,653,059	$	3,018,830	$	3,721,193	$	4,555,770