Pioneer Natural Resources (PXD) 10-Q 6 Nov 13 2013 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 04, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'PXD	'
Entity Registrant Name	'PIONEER NATURAL RESOURCES CO	'
Entity Central Index Key	'0001038357	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	138,667,689

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$744,120	$229,396
Accounts receivable:	'	'
Trade, net	408,240	316,854
Due from affiliates	5,212	3,299
Income taxes receivable	10,168	7,447
Inventories	226,438	197,056
Prepaid expenses	19,984	13,438
Other current assets:	'	'
Derivatives Assets, Current	114,166	279,119
Other	4,933	3,746
Total current assets	1,533,261	1,050,355
Oil and gas properties, using the successful efforts method of accounting:	'	'
Proved properties	15,924,526	14,259,708
Unproved properties	149,782	231,555
Accumulated depletion, depreciation and amortization	-5,086,258	-4,412,913
Total property, plant and equipment	10,988,050	10,078,350
Goodwill	279,687	298,142
Other property and equipment, net	1,258,627	1,217,694
Other assets:	'	'
Investment in unconsolidated affiliate	235,631	204,129
Derivative Assets, Noncurrent	86,574	55,257
Other, net	163,114	165,103
Assets, Total	14,544,944	13,069,030
Accounts payable:	'	'
Trade	954,311	729,942
Due to affiliates	106,073	96,935
Interest payable	36,509	68,083
Income taxes payable	129	208
Deferred Tax Liabilities, Net, Current	60,340	86,481
Other current liabilities:	'	'
Derivative Liabilities, Current	6,436	13,416
Other	51,013	39,725
Total current liabilities	1,214,811	1,034,790
Long-term debt	2,851,212	3,721,193
Derivative Liabilities, Noncurrent	7,719	12,307
Deferred income taxes	2,415,663	2,140,416
Other liabilities	292,788	293,016
Stockholders' equity:	'	'
Common stock, $.01 par value	1,458	1,350
Additional paid-in capital	4,870,566	3,683,934
Treasury stock at cost	-323,348	-510,570
Retained earnings	3,032,531	2,514,640
Total equity attributable to common stockholders	7,581,207	5,689,354
Noncontrolling interests in consolidating subsidiaries	181,544	177,954
Total equity	7,762,751	5,867,308
Commitments and contingencies	'	'
Liabilities and Stockholders' Equity, Total	$14,544,944	$13,069,030

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	145,828,410	134,966,740
Treasury Stock, Shares	7,161,364	11,611,093

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues and other income:	'	'	'	'
Oil and gas	$908,757	$716,327	$2,541,748	$2,077,020
Interest and other	21,087	10,256	41,561	31,450
Derivative gains (losses), net	-102,535	-123,994	-333	243,568
Gain (loss) on disposition of assets, net	-487	12,848	214,917	57,584
Total revenues and other income	826,822	615,437	2,797,893	2,409,622
Costs and expenses:	'	'	'	'
Oil and gas production	181,340	179,687	529,968	461,549
Production and ad valorem taxes	53,946	49,779	162,080	140,070
Depletion, depreciation and amortization	256,260	207,398	736,613	589,737
Impairment of oil and gas properties	0	0	0	444,880
Exploration and abandonments	31,509	27,039	83,109	117,504
General and administrative	73,722	62,567	204,127	180,591
Accretion of discount on asset retirement obligations	3,180	2,497	9,499	7,371
Interest	45,138	54,441	138,678	150,307
Other	24,947	32,011	65,007	86,269
Costs and expenses, Total	670,042	615,419	1,929,081	2,178,278
Income from continuing operations before income taxes	156,780	18	868,812	231,344
Income tax provision	-58,233	-10,614	-309,591	-83,231
Income (loss) from continuing operations	98,547	-10,596	559,221	148,113
Income (loss) from discontinued operations, net of tax	0	32,295	-465	55,007
Net income	98,547	21,699	558,756	203,120
Net income attributable to noncontrolling interests	-7,422	-2,475	-29,705	-39,669
Net income attributable to common stockholders	91,125	19,224	529,051	163,451
Basic earnings per share:	'	'	'	'
Income (loss) from continuing operations attributable to common stockholders	$0.65	($0.11)	$3.87	$0.87
Income (loss) from discontinued operations attributable to common stockholders	$0	$0.26	$0	$0.44
Net income attributable to common stockholders	$0.65	$0.15	$3.87	$1.31
Diluted earnings per share:	'	'	'	'
Income (loss) from continuing operations attributable to common stockholders	$0.65	($0.11)	$3.82	$0.85
Income (loss) from discontinued operations attributable to common stockholders	$0	$0.26	$0	$0.43
Net income attributable to common stockholders	$0.65	$0.15	$3.82	$1.28
Weighted average shares outstanding:	'	'	'	'
Basic	138,586	123,111	135,057	122,874
Diluted	138,946	123,111	136,835	126,111
Dividends declared per share	$0.04	$0.04	$0.08	$0.08
Amounts attributable to common stockholders:	'	'	'	'
Income (loss) from continuing operations	91,125	-13,071	529,516	108,444
Income (loss) from discontinued operations, net of tax	0	32,295	-465	55,007
Net income	$91,125	$19,224	$529,051	$163,451

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$98,547	$21,699	$558,756	$203,120
Other comprehensive activity:	'	'	'	'
Net hedge losses included in continuing operations	0	0	0	4,855
Income tax benefit	0	0	0	-1,725
Other comprehensive activity	0	0	0	3,130
Comprehensive income	98,547	21,699	558,756	206,250
Comprehensive income attributable to the noncontrolling interests	-7,422	-2,475	-29,705	-39,669
Comprehensive income attributable to common stockholders	$91,125	$19,224	$529,051	$166,581

Consolidated_Statement_Of_Equi

Consolidated Statement Of Equity (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2012	$5,867,308	$1,350	$3,683,934	($510,570)	$2,514,640	$177,954
Balance, shares at Dec. 31, 2012	'	123,356,000	'	'	'	'
Stock Issued During Period, Shares, New Issues	10,350,000	10,350,000	'	'	'	'
Stock Issued During Period, Value, New Issues	1,280,916	103	1,280,813	'	'	'
Dividends declared ($0.08 per share)	-11,160	'	'	'	-11,160	'
Exercise of long-term incentive plan stock options, shares	'	222,000	'	'	'	'
Exercise of long-term incentive plan stock options	10,054	'	11	10,043	'	'
Treasury stock purchases, shares	'	-154,000	'	'	'	'
Treasury stock purchases	-20,053	'	'	-20,053	'	'
Stock Issued During Period, Shares, Conversion of Convertible Securities	'	4,381,000	'	'	'	'
Conversion of 2.875% senior convertible notes	-8	'	-197,240	197,232	'	'
Adjustments to Additional Paid in Capital, Income Tax Benefit from Conversion of Convertible Notes	38,415	'	38,415	'	'	'
Tax benefit related to stock-based compensation	12,612	'	12,612	'	'	'
Compensation costs:	'	'	'	'	'	'
Vested compensation awards, net, shares	'	512,000	'	'	'	'
Vested compensation awards, net	0	5	-5	'	'	'
Compensation costs included in net income	52,864	'	52,026	'	'	838
Cash distributions to noncontrolling interests	-26,953	'	'	'	'	-26,953
Net income	558,756	'	'	'	529,051	29,705
Balance at Sep. 30, 2013	$7,762,751	$1,458	$4,870,566	($323,348)	$3,032,531	$181,544
Balance, shares at Sep. 30, 2013	'	138,667,000	'	'	'	'

Consolidated_Statement_Of_Equi1

Consolidated Statement Of Equity (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Stockholders' Equity [Abstract]	'	'	'	'
Dividends declared per share	$0.04	$0.04	$0.08	$0.08

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net income	$558,756	$203,120
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depletion, depreciation and amortization	736,613	589,737
Impairment of oil and gas properties	0	444,880
Exploration expenses, including dry holes	20,238	52,574
Deferred income taxes	300,312	76,180
Gain on disposition of assets, net	-214,917	-57,584
Accretion of discount on asset retirement obligations	9,499	7,371
Discontinued operations	-158	-19,245
Amortization of Financing Costs and Discounts	13,039	26,812
Derivative related activity	122,068	93,088
Amortization of stock-based compensation	52,789	46,899
Amortization of deferred revenue	0	-31,494
Other noncash items	559	-20,998
Change in operating assets and liabilities, net of effects from acquisitions and dispositions:	'	'
Accounts receivable, net	-88,993	-7,946
Income taxes receivable	-2,721	-8,632
Inventories	-28,015	-6,347
Prepaid expenses	-7,289	-6,772
Other current assets	1,778	7,898
Accounts payable	184,345	23,554
Interest payable	-31,574	-16,302
Income taxes payable	-98	-9,566
Other current liabilities	-21,963	-29,757
Net cash provided by operating activities	1,604,268	1,357,470
Cash flows from investing activities:	'	'
Proceeds from disposition of assets	685,188	92,473
Payments for acquisition, net of cash acquired	0	-296,959
Additions to oil and gas properties	-1,987,200	-2,072,800
Additions to other assets and other property and equipment, net	-159,896	-238,803
Net cash used in investing activities	-1,461,908	-2,516,089
Cash flows from financing activities:	'	'
Borrowings under long-term debt	443,864	1,608,618
Principal payments on long-term debt	-1,322,771	-596,000
Proceeds from issuance of common stock, net of issuance costs	1,280,916	0
Distributions to noncontrolling interests	-26,953	-26,970
Borrowings (payments) of other liabilities	237	-894
Exercise of long-term incentive plan stock options and employee stock purchases	10,054	7,072
Purchases of treasury stock	-20,053	-56,677
Excess tax benefits from share-based payment arrangements	12,612	31,330
Payments of financing fees	-8	-6,430
Dividends paid	-5,534	-5,028
Net cash provided by financing activities	372,364	955,021
Net increase (decrease) in cash and cash equivalents	514,724	-203,598
Cash and cash equivalents, beginning of period	229,396	537,484
Cash and cash equivalents, end of period	$744,120	$333,886

Organization_And_Nature_Of_Ope

Organization And Nature Of Operations	9 Months Ended
	Sep. 30, 2013
Organization And Nature Of Operations [Abstract]	'
Organization And Nature Of Operations	'
	Organization and Nature of Operations
	Pioneer Natural Resources Company ("Pioneer" or the "Company") is a Delaware corporation whose common stock is listed and traded on the New York Stock Exchange. The Company is a large independent oil and gas exploration and production company operating in the United States, with field operations in the Permian Basin in West Texas, the Eagle Ford Shale play in South Texas, the Barnett Shale Combo play in North Texas, the Raton field in southeastern Colorado, the Hugoton field in southwest Kansas, the West Panhandle field in the Texas Panhandle and Alaska.

Basis_Of_Presentation

Basis Of Presentation	9 Months Ended
	Sep. 30, 2013
Basis Of Presentation [Abstract]	'
Basis Of Presentation	'
	Basis of Presentation
	Presentation. In the opinion of management, the consolidated financial statements of the Company as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 include all adjustments and accruals, consisting only of normal recurring accrual adjustments, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year.
	Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States ("GAAP") have been condensed in or omitted from this report pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). These consolidated financial statements should be read together with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2012.
	Certain reclassifications have been made to the 2012 financial statement and footnote amounts in order to conform to the 2013 presentation, including classifying the results of the Company's Barnett Shale operations, previously recorded as discontinued operations for the three and nine months ended September 30, 2012, as income from continuing operations.
	Issuance of common stock. In February 2013, the Company issued 10.35 million shares of its common stock and realized $1.3 billion of cash proceeds, net of associated underwriting and offering expenses.
	Noncontrolling interest in consolidated subsidiaries. The Company owns a 0.1 percent general partner interest and a 52.4 percent limited partner interest in Pioneer Southwest Energy Partners L.P. ("Pioneer Southwest"). The Company owns and controls Pioneer Natural Resources GP LLC (the "General Partner"), which manages Pioneer Southwest. Pioneer Southwest owns interests in certain oil and gas properties in the Spraberry field in the Permian Basin of West Texas. The financial position, results of operations and cash flows of Pioneer Southwest are consolidated with those of the Company. Noncontrolling interests in consolidated subsidiaries includes $167.9 million attributable to outstanding Pioneer Southwest common units held by unitholders other than Pioneer or its subsidiaries as of September 30, 2013. See Note C for discussion of a pending merger between the Company and Pioneer Southwest.
	New accounting pronouncements. In July 2013, the Financial Accounting Standards Boards issued Accounting Standards Update ("ASU") 2013-11, "Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists," which provides guidance on the presentation of unrecognized tax benefits. ASU 2013-11 was adopted by the Company during the third quarter of 2013.

Acquisitions_and_Divestitures

Acquisitions and Divestitures	9 Months Ended
	Sep. 30, 2013
Acquisitions and Divestitures [Abstract]	'
Acquisition and Divestitures	'
	Acquisitions and Divestitures
	Premier Silica Business Combination
	On April 2, 2012, a wholly-owned subsidiary of the Company acquired an industrial sand mining business that is now named Premier Silica LLC ("Premier Silica"). Premier Silica's primary mine operations are in Brady, Texas. The Brady mine facilities primarily produce, process and provide sand to the Company for use as proppant in its fracture stimulation of oil and gas wells in Texas. Premier Silica's sand production that is in excess of the Company's sand needs for fracture stimulation and sand production that is not usable for fracture stimulation is primarily sold to third parties for industrial and recreational purposes. The aggregate purchase price of Premier Silica was $297.1 million, including closing adjustments.
	Divestitures Recorded in Continuing Operations
	Southern Wolfcamp. In January 2013, the Company signed an agreement with Sinochem Petroleum USA LLC ("Sinochem"), a U.S. subsidiary of the Sinochem Group, an unaffiliated third party, to sell 40 percent of Pioneer's interest in 207,000 net acres leased by the Company in the horizontal Wolfcamp Shale play in the southern portion of the Spraberry field in West Texas for total consideration of $1.8 billion, including normal closing adjustments. In May 2013, the Company completed the sale to Sinochem for net cash proceeds of $621.2 million, including normal closing adjustments, resulting in a pretax gain of $179.7 million. The Company reduced the carrying value of goodwill and the gain recognized associated with the sale by $18.5 million, reflecting the portion of the Company's goodwill that related to the horizontal Wolfcamp Shale assets that were sold. Sinochem is paying the remaining $1.2 billion of the transaction price by carrying 75 percent of Pioneer's portion of ongoing drilling and facilities costs attributable to the Company's joint operations with Sinochem in the horizontal Wolfcamp Shale play.
	Sales of unproved oil and gas properties. For the nine months ended September 30, 2013, the Company's pretax gain on disposition of assets from continuing operations of $214.9 million was primarily associated with the Southern Wolfcamp transaction described above. Additionally, the Company sold (i) its interest in unproved oil and gas properties adjacent to the Company's West Panhandle field operations for net cash proceeds of $38.1 million, which resulted in a pretax gain of $22.4 million, and (ii) its interest in certain unproved oil and gas properties in the Barnett Shale for net cash proceeds of $11.6 million, which resulted in a pretax gain of $8.7 million.
	For the three months ended September 30, 2012, the Company's pretax gain on disposition of assets was $12.8 million, primarily associated with the sale of the Company's interest in the Cosmopolitan Unit in the Cook Inlet of Alaska to unaffiliated third parties for cash proceeds of $10.1 million, which together with certain Company obligations assumed by the purchasers, resulted in a pretax gain of $12.6 million. Additionally, the Company's pretax gain on the disposition of assets for the nine months ended September 30, 2012 of $57.6 million includes a first quarter 2012 sale of a portion of its interest in an unproved oil and gas properties in the Eagle Ford Shale field for net cash proceeds of $54.7 million, which resulted in a pretax gain of $42.6 million.
	Divestitures Recorded as Discontinued Operations
	South Africa. During the first quarter of 2012, the Company agreed to sell its assets in South Africa ("Pioneer South Africa"), effective January 1, 2012, for $60.0 million of cash proceeds before normal closing and other adjustments, and the buyer's assumption of certain liabilities associated with the assets. In August 2012, the Company completed the sale of Pioneer South Africa for net cash proceeds of $15.9 million, including normal closing adjustments for cash revenues and costs and expenses from the effective date through the date of the sale, resulting in a third quarter 2012 pretax gain of $28.6 million. The Company classified Pioneer South Africa's results of operations as income from discontinued operations, net of tax, in the accompanying consolidated statements of operations.
	For the three and nine months ended September 30, 2012, the Company recognized revenues and other income of $38.1 million and $77.9 million, respectively, and pretax earnings of $37.2 million and $71.2 million, respectively, associated with discontinued operations, principally related to the results of operations and gain from the sale of Pioneer South Africa prior to its divestiture in August 2012.
	Pending Merger
	On August 9, 2013, the Company entered into an Agreement and Plan of Merger with Pioneer Natural Resources USA, Inc., a wholly-owned subsidiary of the Company ("Pioneer USA"), PNR Acquisition Company, LLC, a wholly-owned subsidiary of the Company ("MergerCo"), Pioneer Southwest and the General Partner, which was amended on October 25, 2013 (as amended, the "Merger Agreement").
	Pursuant to the Merger Agreement, MergerCo will merge with and into Pioneer Southwest with Pioneer Southwest surviving the merger (the "Merger"), such that following the Merger, the General Partner will remain a wholly-owned subsidiary of the Company and the sole general partner of Pioneer Southwest, and Pioneer USA will be the sole limited partner of Pioneer Southwest. Except for the common units owned by the Company, all of the common units outstanding as of the closing of the Merger will be cancelled and, except for the dissenting units (as defined in the next paragraph), converted into the right to receive 0.2325 of a share of common stock of the Company per common unit.
	Pursuant to the terms and conditions of the Merger Agreement, common units that are owned by a unitholder (a) other than Pioneer Southwest or its subsidiaries or the Company or its subsidiaries, (b) who does not vote at the special meeting of Pioneer Southwest in favor of the proposal to approve the Merger Agreement and the transactions contemplated thereby, including the Merger, and (c) who is entitled to demand and properly demands appraisal of such common units (the "dissenting units") pursuant to, and who complies in all respects with, the provisions of the Merger Agreement regarding appraisal rights (the "dissenting unitholders") will not be converted into the right to receive the merger consideration, but instead will be entitled to payment of the fair value of such dissenting units pursuant to and in accordance with the provisions of the Merger Agreement, unless and until such dissenting unitholder shall have failed to perfect or shall have effectively withdrawn or lost the appraisal rights. If a dissenting unitholder fails to perfect or effectively withdraws or loses the appraisal rights, then, as of the occurrence of such event or the closing of the Merger, whichever occurs later, each of such dissenting unitholder's dissenting units will be converted into the right to receive 0.2325 of a share of common stock of the Company per common unit.
	The Merger Agreement provides that regular quarterly distributions on the Pioneer Southwest's common units, not to exceed $0.52 per common unit per quarter (which $0.52 per common unit is equivalent to the most recent distribution declared for the quarter ended September 30, 2013), are to continue until the closing of the Merger. Regular distributions for a quarter are declared late in the first month following such quarter, and no distribution will be paid for a quarter if the Merger closes prior to the normal record date for such distribution. No fractional shares of the Company's common stock will be issued in the Merger. In lieu of receiving any fractional share of common stock to which any holder of the Pioneer Southwest's common units would otherwise have been entitled, after aggregating all fractions of shares to which such holder would be entitled, any fractional share will be rounded up to a whole share of common stock of the Company. The closing of the Merger is subject to certain closing conditions, including the approval of the Merger Agreement and the transactions contemplated thereby by the affirmative vote of holders of a majority of the outstanding common units entitled to vote at a special meeting of the unitholders of Pioneer Southwest. Pursuant to a voting agreement, the Company has agreed to cause the common units owned by it and its subsidiaries to be voted in favor of the Merger, which units represent 52.4 percent of Pioneer Southwest's outstanding common units and therefore constitute a sufficient number of common units to approve the Merger at the special meeting of the unitholders of Pioneer Southwest. The parties anticipate that the Merger will close in the fourth quarter of 2013, pending the satisfaction of certain conditions thereto. See Note J for a description of the litigation contingencies associated with the Merger.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or the price paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements are based upon inputs that market participants use in pricing an asset or liability, which are characterized according to a hierarchy that prioritizes those inputs based on the degree to which they are observable.
	Observable inputs represent market data obtained from independent sources, whereas unobservable inputs reflect a company's own market assumptions, which are used if observable inputs are not reasonably available without undue cost and effort. The three input levels of the fair value hierarchy are as follows:
	•	Level 1 – quoted prices for identical assets or liabilities in active markets.
	•	Level 2 – quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates) and inputs derived principally from or corroborated by observable market data by correlation or other means.
	•	Level 3 – unobservable inputs for the asset or liability.
	Assets and liabilities measured at fair value on a recurring basis. The fair value input hierarchy level to which an asset or liability measurement in its entirety falls is determined based on the lowest level input that is significant to the measurement in its entirety.
	The following table presents the Company's assets and liabilities that are measured at fair value as of September 30, 2013:
			Fair Value Measurement at the End of the
			Reporting Period Using
			Quoted Prices		Significant		Significant		Fair Value at September 30, 2013
			in Active		Other		Unobservable
			Markets for		Observable		Inputs
			Identical		Inputs		(Level 3)
			Assets		(Level 2)
			(Level 1)
			(in thousands)
	Recurring fair value measurements
	Assets:
	Trading securities		$	149	$	147	$	—	$	296
	Commodity derivatives		—		191,226		—		191,226
	Interest rate derivatives		—		9,514		—		9,514
	Deferred compensation plan assets		59,939		—		—		59,939
	Total assets		60,088		200,887		—		260,975
	Liabilities:
	Commodity derivatives		—		11,028		—		11,028
	Interest rate derivatives		—		3,127		—		3,127
	Total liabilities		—		14,155		—		14,155
	Total recurring fair value measurements		$	60,088	$	186,732	$	—	$	246,820
	Trading securities and deferred compensation plan assets. The Company's trading securities are comprised of securities that are both actively traded and not actively traded on major exchanges. The Company's deferred compensation plan assets represent investments in equity and mutual fund securities that are actively traded on major exchanges. These investments are measured based on observable prices on major exchanges. As of September 30, 2013, substantially all of the significant inputs to these asset exchange values represented Level 1 independent active exchange market price inputs. Inputs for certain trading securities that are not actively traded on major exchanges were classified as Level 2 inputs.
	Commodity derivatives. The Company's commodity derivatives represent oil, natural gas liquids ("NGL") and gas swap contracts, collar contracts and collar contracts with short puts. The asset and liability measurements for the Company's commodity derivative contracts represent Level 2 inputs in the hierarchy. The Company utilizes discounted cash flow and option-pricing models for valuing its commodity derivatives.
	The asset and liability values attributable to the Company's commodity derivatives were determined based on inputs that include (i) the contracted notional volumes, (ii) independent active market price quotes, (iii) the applicable estimated credit-adjusted risk-free rate yield curve and (iv) the implied rate of volatility inherent in the collar and collar contracts with short puts, which is based on active and independent market-quoted volatility factors.
	Interest rate derivatives. The Company's interest rate derivative assets as of September 30, 2013 represent interest rate swap contracts. The Company utilizes discounted cash flow models for valuing its interest rate derivatives. The net derivative values attributable to the Company's interest rate derivative contracts as of September 30, 2013 are based on (i) the contracted notional amounts, (ii) active market-quoted London Interbank Offered Rate ("LIBOR") yield curves and (iii) the applicable credit-adjusted risk-free rate yield curve. The Company's interest rate derivative asset measurements represent Level 2 inputs in the hierarchy.
	Assets and liabilities measured at fair value on a nonrecurring basis. The Company reviews its long-lived assets for impairment, including oil and gas properties, whenever events or circumstances indicate their carrying values may not be fully recoverable. During the six months ended June 30, 2012, reductions in management's longer-term commodity price outlooks ("Management's Price Outlooks") provided indications of possible impairment of the Company's dry gas properties in the Barnett Shale field in North Texas. As a result of management's assessments, during the second quarter of 2012, the Company recognized a pretax noncash impairment charge of $444.9 million to reduce the carrying value of the Barnett Shale field to its estimated fair value. The Company calculated the estimated fair value of the Barnett Shale field as of June 30, 2012 using a discounted cash flow model. Significant Level 3 assumptions associated with the calculation of Barnett Shale field's discounted future cash flows as of June 30, 2012 included Management's Price Outlooks for (i) oil and gas prices of $87.09 per barrel ("BBL") for oil and $4.64 per million British thermal units ("MMBTU") for gas, (ii) production costs, (iii) capital expenditures, (iv) production and (v) estimated proved reserves and risk-adjusted probable reserves. Management's commodity price outlooks represent longer-term outlooks that are developed based on third-party futures price outlooks as of a measurement date. The expected future net cash flows were discounted using an annual rate of 10 percent to determine estimated fair value.
	Financial instruments 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 September 30, 2013 and December 31, 2012 are as follows:
			September 30, 2013				December 31, 2012
			Carrying		Fair		Carrying		Fair
			Value		Value		Value		Value
			(in thousands)
	Long-term debt		$	2,851,212	$	3,247,459	$	3,721,193	$	4,555,770
	Long-term debt includes the Company's credit facility, the Pioneer Southwest credit facility and the Company's senior notes. The fair value of debt is determined utilizing inputs that are Level 2 measurements in the fair value hierarchy.
	Credit facilities. The fair values of the Company's and Pioneer Southwest's credit facilities are calculated using a discounted cash flow model based on (i) forecasted contractual interest and fee payments, (ii) forward active market-quoted United States Treasury Bill rates (in the case of the Company's credit facility) or LIBOR (in the case of the Pioneer Southwest credit facility) and (iii) the applicable credit-adjustments.
	Senior notes. The Company's senior notes represent debt securities that are not actively traded on major exchanges. The fair values of the Company's senior notes are based on their periodic values as quoted on the major exchanges.
	The Company has other financial instruments consisting primarily of cash equivalents, receivables, prepaid expenses, payables and other current assets and liabilities that approximate fair value due to the nature of the instrument and their relatively short maturities. Non-financial assets and liabilities initially measured at fair value include certain assets acquired and liabilities assumed in a business combination, goodwill and asset retirement obligations.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	Derivative Financial Instruments
	The Company utilizes commodity swap contracts, collar contracts and collar contracts with short puts to (i) reduce the effect of price volatility on the commodities the Company produces and sells or consumes, (ii) support the Company's annual capital budgeting and expenditure plans and (iii) reduce commodity price risk associated with certain capital projects. The Company also, from time to time, utilizes interest rate contracts to reduce the effect of interest rate volatility on the Company's indebtedness.
	Oil production derivative activities. All material physical sales contracts governing the Company's oil production are tied directly to, or are highly correlated with, New York Mercantile Exchange ("NYMEX") West Texas Intermediate ("WTI") oil prices. The Company uses derivative contracts to manage oil price volatility and basis swap contracts to reduce basis risk between NYMEX prices and actual index prices at which the oil is sold.
	The following table sets forth the volumes per day in BBLs associated with the Company's outstanding oil derivative contracts as of September 30, 2013 and the weighted average oil prices per BBL for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014				2015				2016
	Collar contracts with short puts:
	Volume (BBL)		69,000				69,000				85,000				25,000
	Price per BBL:
	Ceiling		$	120.55			$	114.05			$	98.98			$	93.3
	Floor		$	91.39			$	93.7			$	88.06			$	85
	Short put		$	74.22			$	77.61			$	73.06			$	70
	Swap contracts:
	Volume (BBL)		9,750				10,000				—				—
	Price per BBL		$	95.57			$	93.87			$	—			$	—
	Rollfactor swap contracts:
	Volume (BBL)		11,000				19,000				—				—
	NYMEX roll price (a)		$	0.85			$	0.45			$	—			$	—
	Basis swap contracts:
	Cushing to LLS index swap volume (BBL)		3,000				—				—				—
	Price per BBL (b)		$	8.53			$	—			$	—			$	—
	____________________
	(a)	Represents swaps that fix the difference between (i) each day's price per BBL of WTI for the first nearby month less (ii) the price per BBL of WTI for the second nearby NYMEX month, multiplied by .6667; plus (iii) each day's price per BBL of WTI for the first nearby month less (iv) the price per BBL of WTI for the third nearby NYMEX month, multiplied by .3333.
	(b)	Basis differential price between Cushing WTI and Louisiana Light Sweet crude ("LLS").
	NGL production derivative activities. All material physical sales contracts governing the Company's NGL production are tied directly or indirectly to either Mont Belvieu or Conway fractionation facilities' NGL product component prices.
	The following table sets forth the volumes per day in BBLs associated with the Company's outstanding NGL derivative contracts as of September 30, 2013 and the weighted average NGL prices per BBL for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014
	Collar contracts with short puts (a):
	Volume (BBL)		1,064				1,000
	Price per BBL:
	Ceiling		$	105.28			$	109.5
	Floor		$	89.3			$	95
	Short put		$	75.2			$	80
	Collar contracts (b):
	Volume (BBL)		2,500				3,000
	Price per BBL:
	Ceiling		$	12.68			$	13.72
	Floor		$	10.5			$	10.78
	____________________
	(a)	Represent collar contracts with short puts that reduce the price volatility of natural gasoline forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
	(b)	Represent collar contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
	Gas production derivative activities. All material physical sales contracts governing the Company's gas production are tied directly or indirectly to NYMEX Henry Hub ("HH") gas prices or regional index prices where the gas is sold. The Company uses derivative contracts to manage gas price volatility and basis swap contracts to reduce basis risk between HH prices and actual index prices at which the gas is sold.
	The following table sets forth the volumes per day in MMBTUs associated with the Company's outstanding gas derivative contracts as of September 30, 2013 and the weighted average gas prices per MMBTU for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014				2015				2016
	Collar contracts with short puts:
	Volume (MMBTU)		—				115,000				285,000				20,000
	Price per MMBTU:
	Ceiling		$	—			$	4.7			$	5.07			$	5.36
	Floor		$	—			$	4			$	4			$	4
	Short put		$	—			$	3			$	3			$	3
	Collar contracts:
	Volume (MMBTU)		152,500				—				—				—
	Price per MMBTU:
	Ceiling		$	6.22			$	—			$	—			$	—
	Floor		$	4.98			$	—			$	—			$	—
	Swap contracts:
	Volume (MMBTU)		165,870				175,000				20,000				—
	Price per MMBTU		$	5.1			$	4.02			$	4.31			$	—
	Basis swap contracts:
	Volume (MMBTU) (a)		162,500				75,082				30,000				—
	Price per MMBTU		$	(0.22	)		$	(0.19	)		$	(0.18	)		$	—
____________________
(a)	Subsequent to September 30, 2013, the Company entered into additional basis swap contracts for 10,000 MMBTU per day of the Company's 2014 production with a negative price differential of $0.26 per MMBTU between the relevant index price and the NYMEX price.
Interest rate derivative activities. During the second quarter of 2013, the Company terminated its interest rate derivative contracts that locked in a fixed forward annual interest rate of 3.21 percent, for a 10-year period ending in December 2025, on a notional amount of $250 million and received cash proceeds of $482 thousand.
As of September 30, 2013, the Company was a party to interest rate derivative contracts whereby the Company will receive a fixed interest rate of 3.95 percent in exchange for paying a floating interest rate comprised of the three-month LIBOR plus an average rate of 1.11 percent on a notional amount of $400 million through July 15, 2022.
Tabular disclosure of derivative financial instruments. All of the Company's derivatives are accounted for as non-hedge derivatives as of September 30, 2013 and December 31, 2012 and therefore all changes in the fair values of its derivative contracts are recognized as gains or losses in the earnings of the periods in which they occur. The Company classifies the fair value amounts of derivative assets and liabilities as net current or noncurrent derivative assets or net current or noncurrent derivative liabilities, whichever the case may be, by commodity and counterparty. The Company enters into derivatives under master netting arrangements, which, in an event of default, allows the Company to offset payables to and receivables from the defaulting counterparty.
The aggregate fair value of the Company's derivative instruments reported in the consolidated balance sheets by type and counterparty, including the classification between current and noncurrent assets and liabilities, consists of the following:
Fair Value of Derivative Instruments as of September 30, 2013
Type		Consolidated Balance Sheet		Fair				Gross Amounts Offset in the Consolidated Balance Sheet				Net Fair Value Presented in the Consolidated Balance Sheet
		Location		Value
				(in thousands)
Derivatives not designated as hedging instruments
Asset Derivatives:
Commodity price derivatives		Derivatives - current		$	117,191			$	(12,368	)		$	104,823
Interest rate derivatives		Derivatives - current		$	9,342			$	—			$	9,342
Commodity price derivatives		Derivatives - noncurrent		$	96,371			$	(9,968	)		86,403
Interest rate derivatives		Derivatives - noncurrent		$	15,767			$	(15,595	)		$	172
												$	200,740
Liability Derivatives:
Commodity price derivatives		Derivatives - current		$	18,804			$	(12,368	)		$	6,436
Commodity price derivatives		Derivatives - noncurrent		$	14,560			$	(9,968	)		4,592
Interest rate derivatives		Derivatives - noncurrent		$	18,722			$	(15,595	)		$	3,127
												$	14,155
Fair Value of Derivative Instruments as of December 31, 2012
Type		Consolidated Balance Sheet		Fair				Gross Amounts Offset in the Consolidated Balance Sheet				Net Fair Value Presented in the Consolidated Balance Sheet
		Location		Value
				(in thousands)
Derivatives not designated as hedging instruments
Asset Derivatives:
Commodity price derivatives		Derivatives - current		$	286,805			$	(7,686	)		$	279,119
Commodity price derivatives		Derivatives - noncurrent		$	61,618			$	(6,361	)		55,257
												$	334,376
Liability Derivatives:
Commodity price derivatives		Derivatives - current		$	21,102			$	(7,686	)		$	13,416
Commodity price derivatives		Derivatives - noncurrent		$	8,944			$	(6,361	)		2,583
Interest rate derivatives		Derivatives - noncurrent		$	9,724			$	—			9,724
												$	25,723
The Company uses credit and other financial criteria to evaluate the credit standing of, and to select, counterparties to its derivative instruments. Although the Company does not obtain collateral or otherwise secure the fair value of its derivative instruments, associated credit risk is mitigated by the Company's credit risk policies and procedures.
The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations:
Derivatives Not Designated as Hedging		Location of Gain / (Loss) Recognized in		Three Months Ended								Nine Months Ended
				September 30,								September 30,
Instruments		Earnings on Derivatives		2013				2012				2013				2012
				(in thousands)
Commodity price derivatives		Derivative gains (losses), net		$	(108,922	)		$	(118,795	)		$	(16,926	)		$	267,806
Interest rate derivatives		Derivative gains (losses), net		6,387				(5,199		)		16,593				(24,238		)
Total				$	(102,535	)		$	(123,994	)		$	(333	)		$	243,568

Exploratory_Costs

Exploratory Costs	9 Months Ended
	Sep. 30, 2013
Exploratory Cost Disclosure [Abstract]	'
Exploratory Costs	'
	Exploratory Costs
	The Company capitalizes exploratory well and project costs until a determination is made that the well or project has either found proved reserves, is impaired or is sold. After an exploratory well has been completed and found oil and gas reserves, a determination may be pending as to whether the oil and gas reserves can be classified as proved. In those circumstances, the Company continues to capitalize the well or project costs pending the determination of proved status if (i) the well has found a sufficient quantity of reserves to justify its completion as a producing well and (ii) the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. The Company's capitalized exploratory well and project costs are presented in proved properties in the accompanying consolidated balance sheets. If the exploratory well or project is determined to be impaired, the impaired costs are charged to exploration and abandonments expense.
	The following table reflects the Company's capitalized exploratory well and project activity during the three and nine months ended September 30, 2013:
		Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
		(in thousands)
	Beginning capitalized exploratory costs	$	255,001		$	212,670
	Additions to exploratory costs pending the determination of proved reserves	252,884			945,001
	Reclassification due to determination of proved reserves	(168,299		)	(720,338		)
	Disposition of assets	(5,251		)	(92,955		)
	Exploratory well costs charged to exploration expense	433			(9,610		)
	Ending capitalized exploratory costs	$	334,768		$	334,768
	The following table provides an aging, as of September 30, 2013 and December 31, 2012, of capitalized exploratory costs and the number of projects for which exploratory costs have been capitalized for a period greater than one year based on the date drilling was completed:
		September 30, 2013			December 31, 2012
		(in thousands, except project counts)
	Capitalized exploratory costs that have been suspended:
	One year or less	$	188,511		$	190,678
	More than one year	146,257			21,992
		$	334,768		$	212,670
	Number of projects with exploratory costs that have been suspended for a period greater than one year	2			1
	Alaska - Oooguruk. As of September 30, 2013 and December 31, 2012, the Company had $30.8 million and $22.0 million, respectively, of suspended well costs recorded for the K-13 well in the Alaska Oooguruk field. Drilling on the K-13 well was completed during September 2011. During well completion operations, subsurface damages were sustained. The Company performed repairs and recompleted the well during the third quarter of 2013. The well is currently undergoing production tests and may require additional stimulation work that, if required, is expected to be completed during the first quarter of 2014.
	Alaska - Nuna. The Company's Nuna project, which has $115.5 million of suspended project costs as of September 30, 2013, includes the Nuna-1 exploration well that was drilled during 2012 to test the Torok formation and a second appraisal well that was drilled and logged during the first quarter of 2013. The Company flow-tested the Nuna-1 well during the second quarter of 2012 and again in the first quarter of 2013. The second appraisal well encountered a mechanical problem and could not be flow-tested before the end of the winter drilling season. The results of the flow tests on the Nuna-1 well and the log data from the second Nuna well are both very encouraging. The Company is currently conducting a front-end engineering design ("FEED") study to evaluate the potential for onshore production facilities to support the project.
	See Note O for information regarding the Company's October 2013 agreement to sell its Alaskan subsidiary.

LongTerm_Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	Long-term Debt
	The Company's long-term debt consists of senior notes and revolving credit facilities, including the effects of net deferred fair value hedge losses and issuance discounts. As of September 30, 2013, the Company and Pioneer Southwest were in compliance with all of their debt covenants.
	Corporate credit facility. The Company maintains a corporate credit facility (the "Credit Facility") with a syndicate of financial institutions that has aggregate loan commitments of $1.5 billion that expires in December 2017. As of September 30, 2013, the Company had no outstanding borrowings under the Credit Facility.
	Pioneer Southwest credit facility. Pioneer Southwest maintains a Credit Agreement (the "Pioneer Southwest Credit Facility") with a syndicate of financial institutions that has aggregate loan commitments of $300 million that expires in March 2017. As of September 30, 2013, Pioneer Southwest had outstanding borrowings of $201.0 million under the Pioneer Southwest Credit Facility. Pioneer Southwest's borrowing capacity under the Pioneer Southwest Credit Facility is subject to a covenant requiring that Pioneer Southwest maintain a specified ratio of the net present value of Pioneer Southwest's projected future cash flows from its oil and gas assets to total debt, with the variables on which the calculation of net present value is based (including assumed commodity prices and discount rates) being subject to adjustment by the lenders. The net present value covenant limits Pioneer Southwest's available borrowing capacity under the Pioneer Southwest Credit Facility to $68.6 million as of September 30, 2013.
	Convertible senior notes. As of December 31, 2012, the Company had $479.9 million of 2.875% Convertible Senior Notes due 2038 ("Convertible Senior Notes") outstanding. During December 2012 and March 2013, the Company's stock price met the price threshold that caused the Convertible Senior Notes to be convertible during the six months ended June 30, 2013 at the option of the holders into a combination of cash and the Company's common stock based on a formula set forth in the indenture supplement pursuant to which the Convertible Senior Notes were issued. In addition, on April 15, 2013, the Company announced that it would exercise its option to redeem all Convertible Senior Notes that had not been converted by the holders before May 16, 2013. Associated therewith, during the six months ended June 30, 2013, holders of $479.1 million principal amount of the Convertible Senior Notes exercised their right to convert their Convertible Senior Notes into cash and shares of the Company's common stock. The Company paid the tendering holders $479.1 million of cash and issued to the tendering holders 4.4 million shares of the Company's common stock during the six months ended June 30, 2013, in accordance with the terms of the Convertible Senior Notes indenture agreement. On May 16, 2013, the Company paid $845 thousand in principal and interest to redeem all Convertible Senior Notes that remained outstanding.

Incentive_Plans

Incentive Plans	9 Months Ended
	Sep. 30, 2013
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Incentive Plans	'
	Incentive Plans
	Stock-based compensation
	For the three and nine months ended September 30, 2013, the Company recorded $32.5 million and $85.3 million, respectively, of stock-based compensation expense for all plans, as compared to $22.8 million and $66.0 million, respectively, for the same periods of 2012. As of September 30, 2013, there was $178.1 million of unrecognized compensation expense related to unvested share- and unit-based compensation plan awards, including $56.6 million attributable to stock-based awards that are expected to be settled on their vesting date in cash, rather than in equity shares ("Liability Awards"). This compensation will be recognized over the remaining vesting periods of the awards, which is a period of less than three years on a weighted average basis. As of September 30, 2013 and December 31, 2012, accounts payable – due to affiliates includes $24.5 million and $18.8 million, respectively, of liabilities attributable to Liability Awards.
	The following table summarizes the activity that occurred during the nine months ended September 30, 2013, for each type of share-based incentive award issued by Pioneer or Pioneer Southwest:
		Restricted		Restricted		Performance		Stock		Pioneer		Pioneer
		Stock Equity		Stock		Units		Options		Southwest		Southwest
		Awards		Liability						LTIP		LTIP
				Awards						Restricted		Phantom
										Units		Units
	Outstanding as of December 31, 2012	1,512,762		405,916		91,370		467,486		7,496		102,644
	Awards granted	433,311		250,641		94,917		—		—		32,242
	Awards vested	(509,659	)	(197,769	)	—		—		(7,496	)	(35,118	)
	Options exercised	—		—		—		(166,474	)	—		—
	Awards forfeited	(65,950	)	(29,664	)	(10,842	)	(11,085	)	—		—
	Outstanding as of September 30, 2013	1,370,464		429,124		175,445		289,927		—		99,768
	Postretirement Benefit Obligations
	As of September 30, 2013 and December 31, 2012, the Company had $8.3 million and $9.7 million, respectively, of unfunded accumulated postretirement benefit obligations, the current and noncurrent portions of which are included in other current liabilities and other liabilities, respectively, in the accompanying consolidated balance sheets. These obligations are comprised of five unfunded plans, of which four relate to predecessor entities that the Company acquired in prior years, and one funded plan for which the Company assumed sponsorship in conjunction with the acquisition of Premier Silica.
	The unfunded plans had no assets as of September 30, 2013 or December 31, 2012. The Company's funding policy for the Premier Silica plan is to contribute amounts sufficient to meet legal funding requirements, plus any additional amounts that the Company may determine to be appropriate considering the funded status of the plan, tax deductibility, the cash flow generated by the Company and other factors. The Company continually reassesses the amount and timing of any discretionary contributions and may elect to make such contributions in future periods.

Asset_Retirement_Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligations	'
	Asset Retirement Obligations
	The Company's asset retirement obligations primarily relate to the future plugging and abandonment of wells and facilities. The following table summarizes the Company's asset retirement obligation activity during the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands)
	Beginning asset retirement obligations		$	191,129		$	145,457		$	197,754		$	136,742
	Liabilities assumed in acquisitions		—			—			—			8,515
	New wells placed on production		1,234			1,251			3,682			3,662
	Changes in estimates (a)		—			48			(5,597		)	1,651
	Dispositions		—			(2,536		)	(4,310		)	(2,536		)
	Liabilities settled		(4,721		)	(4,507		)	(10,218		)	(13,249		)
	Accretion of discount		3,180			2,497			9,499			7,371
	Accretion of discount from integrated services (b)		1			23			13			77
	Ending asset retirement obligations		$	190,823		$	142,233		$	190,823		$	142,233
	_____________________
	(a)	The changes in estimates during the nine months ended September 30, 2013 are attributable to lengthening the economic lives of certain wells, which reduced the present values of the associated asset retirement obligations.
	(b)	Accretion of discount from integrated services includes Premier Silica accretion expense, which is recorded as a reduction in third-party income from vertical integration services in interest and other income in the Company's accompanying consolidated statements of operations. See Note K for more information about interest and other income.
	The Company records the current and noncurrent portions of asset retirement obligations in other current liabilities and other liabilities, respectively, in the accompanying consolidated balance sheets. As of September 30, 2013 and December 31, 2012, the current portions of the Company's asset retirement obligations were $13.4 million and $13.3 million, respectively.

Commitments_And_Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments And Contingencies	'
	Commitments and Contingencies
	The Company is a party to proceedings and claims incidental to its business. While many of these matters involve inherent uncertainty, the Company believes that the amount of the liability, if any, ultimately incurred with respect to such proceedings and claims will not have a material adverse effect on the Company's consolidated financial position as a whole or on its liquidity, capital resources or future annual results of operations. The Company records reserves for contingencies when information available indicates that a loss is probable and the amount of the loss can be reasonably estimated.
	Lawsuits filed in state and federal courts in Texas relating to the Merger. On May 15, 2013, David Flecker, a purported unitholder of Pioneer Southwest, filed a class action petition on behalf of Pioneer Southwest's unitholders and a derivative suit on behalf of Pioneer Southwest against the Company, Pioneer USA, the General Partner and the directors of the General Partner, in the 134th Judicial District of Dallas County, Texas (the "Flecker Lawsuit"). A similar class action petition and derivative suit was filed against the same defendants on May 20, 2013, in the 160th Judicial District of Dallas County, Texas, by purported unitholder Vipul Patel (the "Patel Lawsuit"). On August 27, 2013, the plaintiff in the Flecker Lawsuit filed an amended petition. On September 3, 2013, the court consolidated the Patel Lawsuit into the Flecker Lawsuit (as consolidated, the "Texas State Court Lawsuit"), and the plaintiffs filed a consolidated derivative and class action petition on September 5, 2013.
	The Texas State Court Lawsuit alleges, among other things, that the consideration offered by the Company in the Merger is unfair and inadequate and that, by pursuing a transaction that is the result of an allegedly conflicted and unfair process, the defendants have breached their duties under Pioneer Southwest's partnership agreement as well as the implied covenant of good faith and fair dealing, and are engaging in self-dealing. Specifically, the lawsuit alleges that the director defendants: (i) engaged in self-dealing, failed to act in good faith toward Pioneer Southwest, and breached their duties owed to Pioneer Southwest; (ii) failed to properly value Pioneer Southwest and its various assets and operations and ignored or failed to protect against the numerous conflicts of interest arising out of the proposed transaction; and (iii) breached the implied covenant of good faith and fair dealing by engaging in a flawed merger process. The Texas State Court Lawsuit also alleges that the Company, Pioneer USA and the General Partner aided and abetted the director defendants in their purported breach of fiduciary duties.
	Based on these allegations, the plaintiffs in the Texas State Court Lawsuit seek to enjoin the defendants from proceeding with or consummating the proposed transaction. To the extent that the Merger is implemented before relief is granted, the plaintiffs seek to have the Merger rescinded. The plaintiffs also seek money damages and attorneys' fees. The defendants have filed a motion to dismiss the Texas State Court Lawsuit based on improper forum.
	On August 21, 2013, Allan H. Beverly, a purported unitholder, filed a class action complaint against Pioneer Southwest, the Company, Pioneer USA, MergerCo and the directors of the General Partner in the United States District Court for the Northern District of Texas (the "Beverly Lawsuit"). The Beverly Lawsuit alleges that the defendants breached their fiduciary duties by agreeing to the Merger by means of an unfair process and for an unfair price. Specifically, the lawsuit alleges that the director defendants: (i) failed to maximize the value of Pioneer Southwest to its public unitholders and took steps to avoid competitive bidding; (ii) failed to properly value Pioneer Southwest; and (iii) ignored or failed to protect against the numerous conflicts of interest arising out of the proposed transaction. The Beverly Lawsuit also alleges that the Company, Pioneer USA and MergerCo aided and abetted the director defendants in their purported breach of fiduciary duties.
	On September 13, 2013, Douglas Shelton, another purported unitholder, filed a class action complaint against the same defendants in the Beverly Lawsuit (as well as the General Partner) in the same court as the Beverly Lawsuit (the "Shelton Lawsuit"). The Shelton Lawsuit makes similar allegations to the Beverly Lawsuit, and also alleges that Section 7.9 of Pioneer Southwest's partnership agreement fails to alter or eliminate the defendants' common law fiduciary duties owed to unitholders in the context of the Merger. Specifically, the lawsuit alleges: (i) that the Company, as controlling unitholder, failed to fulfill its fiduciary duties in connection with the Merger because it purportedly cannot establish that the proposed Merger is the result of a fair process that will return a fair price to the unaffiliated unitholders of Pioneer Southwest; (ii) that the director defendants breached their fiduciary duties by failing to exercise due care and diligence in connection with the proposed Merger because the proposed Merger is purportedly not the result of a fair process that will return a fair price to the unaffiliated unitholders; and (iii) that the non-director defendants aided and abetted the director defendants in their purported breach of fiduciary duties. The plaintiffs in the Beverly Lawsuit and the Shelton Lawsuit (together, the "Federal Lawsuits") seek the same remedies as the plaintiffs in the Texas State Court Lawsuit.
	On September 26, 2013, representatives of the plaintiffs in the Texas State Court Lawsuit and the Federal Lawsuits and representatives of the defendants in such lawsuits entered into a memorandum of understanding ("the memorandum of understanding") to settle the claims and allegations made in such lawsuits. The memorandum of understanding provides the plaintiffs with a period of confirmatory discovery during which the plaintiffs can confirm the fairness and reasonableness of the settlement contemplated by the memorandum of understanding. The parties agreed to use their reasonable best efforts to agree upon, execute and present to the Dallas County, Texas District Court a stipulation of settlement, which will provide for, among other things, a certification, for settlement purposes only, of the applicable class of unitholders to which the settlement will apply. Furthermore, the stipulation of settlement will provide for a full and complete discharge, dismissal with prejudice, settlement and release of all claims, suits and causes of action by the plaintiffs (other than appraisal rights under the Merger Agreement) against the defendants and their representatives arising out of or relating to the allegations made in the Texas State Court Lawsuit and the Federal Lawsuits, the Merger or any deliberations, negotiations, disclosures, omissions, press releases, statements or misstatements in connection therewith, any fiduciary or other obligations in respect of the Merger or any alternative transaction or under Pioneer Southwest's partnership agreement, or any costs and expenses associated with settlement other than as provided in the stipulation. All proceedings relating to the allegations made in the Texas State Court Lawsuit other than with respect to the settlement have been stayed. As part of the consideration for the settlement, the Merger Agreement was amended to provide for contractual appraisal rights for the unitholders. The parties to the memorandum of understanding have agreed to use their reasonable best efforts to obtain the agreement of any plaintiffs filing similar lawsuits to the Texas State Court Lawsuit or the Federal Lawsuits (whether filed in any state or federal court) to become party to the memorandum of understanding and the related settlement, and it is a condition to the consummation of the final settlement that any such plaintiffs join the settlement or such similar lawsuits otherwise be dismissed with prejudice prior to the final approval of the settlement. On October 15, 2013, the plaintiffs in the Beverly Lawsuit voluntarily dismissed all claims in the lawsuit in accordance with the memorandum of understanding. On October 16, 2013, the plaintiffs in the Shelton Lawsuit likewise voluntarily dismissed all claims in the lawsuit in accordance with the memorandum of understanding. There can be no assurance that a final settlement will be consummated.
	Lawsuit filed in the Delaware Court of Chancery relating to the Merger. On September 23, 2013, Patrick Wilson, another purported unitholder, filed a class action petition on behalf of the unitholders against Pioneer USA, MergerCo, Pioneer Southwest, the General Partner and the directors of the General Partner in the Court of Chancery of the State of Delaware (the "Wilson Lawsuit"). The Wilson Lawsuit alleges that the director defendants breached their purported fiduciary obligations to the unitholders by engaging in a process that undervalued Pioneer Southwest and which allegedly constitutes gross negligence, recklessness, willful misconduct, bad faith or knowing violations of law. Additionally, the Wilson Lawsuit alleges that the non-director defendants aided and abetted the purported breaches of fiduciary duties of the director defendants. The Wilson Lawsuit seeks the same remedies as the plaintiffs in the Texas State Court Lawsuit and the Federal Lawsuits. As of the date of this Report, the plaintiffs in the Wilson Lawsuit have not joined the memorandum of understanding.
	The Company cannot predict the outcome of these or any other lawsuits that might be filed subsequent to the date of the filing of this Report, nor can the Company predict the amount of time and expense that will be required to resolve these lawsuits. See Note C for a description of the Merger Agreement.

Interest_And_Other_Income

Interest And Other Income	9 Months Ended
	Sep. 30, 2013
Interest and Other Income [Abstract]	'
Interest And Other Income	'
	Interest and Other Income
	The following table provides the components of the Company's interest and other income for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended				Nine Months Ended
			September 30,				September 30,
			2013		2012		2013			2012
			(in thousands)
	Alaskan Petroleum Production Tax credits and refunds (a)		$	12,864	$	3,979	$	38,633		$	15,825
	Equity interest in income of unconsolidated affiliate (b)		3,941		1,151		10,024			2,696
	Other income		1,554		1,373		5,119			3,608
	Deferred compensation plan income		381		204		2,363			1,727
	Interest income		81		84		256			1,400
	Income (loss) from vertical integration services (c)		2,266		3,465		(14,834		)	6,194
	Total interest and other income		$	21,087	$	10,256	$	41,561		$	31,450
	____________________
	(a)	The Company earns Alaskan Petroleum Production Tax ("PPT") credits on qualifying capital expenditures. The Company recognizes income from PPT credits when they are realized through cash refunds or as reductions in production and ad valorem taxes if realizable as offsets to PPT expense.
	(b)	The Company, along with its joint venture partner, formed EFS Midstream LLC ("EFS Midstream") in 2010 to operate gathering facilities in the Eagle Ford Shale area. The Company accounts for its investment in EFS Midstream using the equity method. EFS Midstream is providing gathering, treating and transportation services for the Company during a 20-year contractual term.
	(c)	Income (loss) from vertical integration services represent net margins that result from Company-provided fracture stimulation, drilling and related service operations, which are ancillary to and supportive of the Company's oil and gas joint operating activities, and do not represent intercompany transactions. For the three and nine months ended September 30, 2013, these net margins include $103.1 million and $206.3 million of gross vertical integration revenues, respectively, and $100.8 million and $221.1 million of total vertical integration costs and expenses, respectively. For the same periods in 2012, these net margins include $61.9 million and $223.6 million of gross vertical integration revenues, respectively, and $58.4 million and $217.4 million of total vertical integration costs and expenses, respectively.

Other_Expense

Other Expense	9 Months Ended
	Sep. 30, 2013
Other Expense [Abstract]	'
Other Expense	'
	Other Expense
	The following table provides the components of the Company's other expense for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended				Nine Months Ended
			September 30,				September 30,
			2013		2012		2013		2012
			(in thousands)
	Transportation commitment charge (a)		$	13,482	$	9,694	$	31,228	$	27,374
	Other		2,825		2,586		11,138		12,709
	Above market and idle drilling and well services equipment rates (b)		1,293		12,808		9,744		23,553
	Contingency and environmental accrual adjustments		4,701		70		6,782		772
	Inventory impairment (c)		2,646		46		5,096		6,093
	Terminated drilling rig contract charges (d)		—		6,807		1,019		15,768
	Total other expense		$	24,947	$	32,011	$	65,007	$	86,269
	____________________
	(a)	Primarily represents firm transportation payments on excess pipeline capacity commitments.
	(b)	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that are above current market rates and idle drilling rig fees, neither of which are charged to joint operations.
	(c)	Represents valuation charges on excess or damaged materials and supplies inventories.
	(d)	Primarily represents charges to terminate drilling rig contracts that are not required to meet planned activities.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company's income tax benefits or provisions attributable to income from continuing operations consisted of the following for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in thousands)
	Current	$	8,341		$	8,275		$	(9,279	)	$	(7,051	)
	Deferred	(66,574		)	(18,889		)	(300,312		)	(76,180		)
	Income tax provision	$	(58,233	)	$	(10,614	)	$	(309,591	)	$	(83,231	)
	For the three and nine months ended September 30, 2013, the Company's effective tax rate, excluding income attributable to the noncontrolling interest, was 39 percent and 37 percent, respectively, as compared to effective rates of (432) percent and 43 percent for the same respective periods in 2012. The Company's effective tax rates differ from the U.S. statutory rate of 35 percent primarily due to state income tax apportionments and nondeductible expenses.
	At September 30, 2013, the Company had unrecognized tax benefits of $21.2 million resulting from net operating loss carryovers and alternative minimum tax credits obtained from the acquisition of Premier Silica.  The unrecognized tax benefit is recorded as a reduction of the associated deferred tax asset and, if recognized, would affect the annual effective tax rate.  The Company expects to resolve uncertainties regarding the unrecognized tax benefit within twelve months of September 30, 2013.  There were no unrecognized tax benefits as of December 31, 2012.
	The Company files income tax returns in the U.S. federal and various state and foreign jurisdictions. The Internal Revenue Service has closed examinations of the 2011 and prior tax years and, with few exceptions, the Company believes that it is no longer subject to examinations by state and foreign tax authorities for years before 2008. As of September 30, 2013, no adjustments had been proposed in any jurisdiction that would have a significant effect on the Company's liquidity, future results of operations or financial position.

Net_Income_Loss_Per_Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Net Income (Loss) Per Share	'
	Net Income Per Share
	The Company uses the two-class method of calculating net income per share because certain of the Company's and its consolidated subsidiaries' unvested share-based awards qualify as participating securities. Participating securities participate in the Company's dividend or partnership distributions and are assumed to participate in the Company's undistributed income proportionate to their share of the weighted average outstanding common shares, but are not assumed to participate in the Company's net losses because they are not contractually obligated to do so. Accordingly, allocations of earnings to participating securities are included in the Company's calculations of basic and diluted earnings per share from continuing operations, discontinued operations and net income attributable to common stockholders.
	During periods in which the Company realizes a loss from continuing operations attributable to common stockholders, securities or other contracts to issue common stock would be dilutive to loss per share from continuing operations; therefore, conversion into common stock is assumed not to occur.
	The following tables reconcile the Company's net income (loss) attributable to common stockholders to basic net income (loss) attributable to common stockholders and diluted net income (loss) attributable to common stockholders for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended September 30, 2013										Nine Months Ended September 30, 2013
			Continuing				Discontinued			Total			Continuing			Discontinued			Total
			Operations				Operations						Operations			Operations
			(in thousands)
	Net income (loss) attributable to common stockholders		$	91,125			$	—		$	91,125		$	529,516		$	(465	)	$	529,051
	Participating basic earnings		(1,239		)		—			(1,239		)	(6,729		)	—			(6,729		)
	Basic net income (loss) attributable to common stockholders		89,886				—			89,886			522,787			(465		)	522,322
	Reallocation of participating earnings		3				—			3			102			—			102
	Diluted income (loss) attributable to common stockholders		$	89,889			$	—		$	89,889		$	522,889		$	(465	)	$	522,424
			Three Months Ended September 30, 2012										Nine Months Ended September 30, 2012
			Continuing				Discontinued			Total			Continuing			Discontinued			Total
			Operations				Operations						Operations			Operations
			(in thousands)
	Net income (loss) attributable to common stockholders		$	(13,071	)		$	32,295		$	19,224		$	108,444		$	55,007		$	163,451
	Participating basic earnings		—				(357		)	(357		)	(1,658		)	(841		)	(2,499		)
	Basic net income (loss) attributable to common stockholders		(13,071		)		31,938			18,867			106,786			54,166			160,952
	Reallocation of participating earnings		—				—			—			89			45			134
	Diluted income (loss) attributable to common stockholders		$	(13,071	)		$	31,938		$	18,867		$	106,875		$	54,211		$	161,086
	The following table is a reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013		2012
			(in thousands)
	Weighted average common shares outstanding:
	Basic		138,586			123,111			135,057		122,874
	Dilutive common stock options (a)		128			—			141		196
	Convertible Senior Notes dilution (a)		—			—			1,453		2,866
	Contingently issuable performance unit shares (a)		232			—			184		175
	Diluted		138,946			123,111			136,835		126,111
	____________________
	(a)	The following common share equivalents were excluded from the weighted average diluted shares for the three months ended September 30, 2012 because they would have been anti-dilutive to the loss recorded for the period: 179,449 outstanding options to purchase the Company's common stock, 184,545 common shares attributable to unvested performance units and 3,311,845 common shares issuable if holders of the Company's 2.875% Convertible Senior Notes had exercised their conversion rights (see Note G). Options to purchase 185,722 shares of the Company's common stock were excluded from the diluted income per share calculations for the nine months ended September 30, 2012 because they would have been anti-dilutive to the calculation. For the nine months ended September 30, 2013, options to purchase 34,842 shares of the Company's common stock were excluded from the diluted income per share calculation because they would have been anti-dilutive to the calculation.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	Distribution declaration. In October 2013, Pioneer Southwest declared a cash distribution of $0.52 per common unit for the period from July 1 to September 30, 2013. The distribution is payable on November 12, 2013 to unitholders of record at the close of business on November 4, 2013. Associated therewith, Pioneer Southwest expects to pay $18.6 million of aggregate distributions.
	Merger Agreement. On October 25, 2013, the Company entered into an amendment to the Agreement and Plan of Merger with Pioneer USA, MergerCo, Pioneer Southwest and the General Partner dated August 9, 2013. Pursuant to the Merger Agreement, MergerCo will merge with and into Pioneer Southwest, with Pioneer Southwest surviving the Merger, such that following the Merger, the General Partner will remain a wholly-owned subsidiary of Pioneer and the sole general partner of Pioneer Southwest, and Pioneer USA will be the sole limited partner of Pioneer Southwest. Except for the common units owned by the Company, all of the common units outstanding as of the closing of the Merger will be cancelled and, except for the dissenting units, converted into the right to receive 0.2325 of a share of common stock of the Company per common unit. The closing of the Merger is subject to the satisfaction of certain closing conditions. See Note C for a description of the Merger Agreement.
	Divestiture. In October 2013, the Company announced that it entered into a purchase and sale agreement with an unaffiliated third party to sell 100 percent of the equity in Pioneer's Alaska subsidiary, representing all of the Company's net assets in Alaska ("Pioneer Alaska"), for cash proceeds of $550.0 million, before normal closing adjustments.  Closing of the transaction is expected to occur during the fourth quarter of 2013 or the first quarter of 2014 and is subject to certain conditions, including governmental approvals, buyer's arrangement of financing and other customary closing conditions. Associated with the sale of Pioneer Alaska, the Company expects to record a pretax noncash loss of approximately $350 million during the three months ended December 31, 2013.  The financial and operating results of Pioneer Alaska's activities are expected to be reflected as discontinued operations for the quarter ending December 31, 2013 and for all prior periods that will be presented in the Company's annual report on Form 10-K for the year ended December 31, 2013. No impairment of Pioneer Alaska's net assets was recorded as of September 30, 2013 due to (i) the probability-weighted undiscounted cash flows of Pioneer Alaska net assets exceeding their carrying value at September 30, 2013 and (ii) the uncertainty regarding the willingness of third parties to purchase Pioneer Alaska on terms and at a price acceptable to the Company, which precluded held for sale criteria as of September 30, 2013. No assurance can be given that the closing conditions will be satisfied or that the sale will occur in accordance with the terms described above.

Basis_Of_Presentation_Policies

Basis Of Presentation (Policies)	9 Months Ended
	Sep. 30, 2013
Basis Of Presentation [Abstract]	'
Presentation	'
	Presentation. In the opinion of management, the consolidated financial statements of the Company as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 include all adjustments and accruals, consisting only of normal recurring accrual adjustments, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year.
	Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States ("GAAP") have been condensed in or omitted from this report pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). These consolidated financial statements should be read together with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2012.
	Certain reclassifications have been made to the 2012 financial statement and footnote amounts in order to conform to the 2013 presentation, including classifying the results of the Company's Barnett Shale operations, previously recorded as discontinued operations for the three and nine months ended September 30, 2012, as income from continuing operations.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Schedule of assets and liabilities measured at fair value on a recurring basis	'
	The following table presents the Company's assets and liabilities that are measured at fair value as of September 30, 2013:
		Fair Value Measurement at the End of the
		Reporting Period Using
		Quoted Prices		Significant		Significant		Fair Value at September 30, 2013
		in Active		Other		Unobservable
		Markets for		Observable		Inputs
		Identical		Inputs		(Level 3)
		Assets		(Level 2)
		(Level 1)
		(in thousands)
	Recurring fair value measurements
	Assets:
	Trading securities	$	149	$	147	$	—	$	296
	Commodity derivatives	—		191,226		—		191,226
	Interest rate derivatives	—		9,514		—		9,514
	Deferred compensation plan assets	59,939		—		—		59,939
	Total assets	60,088		200,887		—		260,975
	Liabilities:
	Commodity derivatives	—		11,028		—		11,028
	Interest rate derivatives	—		3,127		—		3,127
	Total liabilities	—		14,155		—		14,155
	Total recurring fair value measurements	$	60,088	$	186,732	$	—	$	246,820
Schedule of carrying values and financial instruments 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 September 30, 2013 and December 31, 2012 are as follows:
		September 30, 2013				December 31, 2012
		Carrying		Fair		Carrying		Fair
		Value		Value		Value		Value
		(in thousands)
	Long-term debt	$	2,851,212	$	3,247,459	$	3,721,193	$	4,555,770

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Schedule of oil derivative contracts volume and weighted average price	'
	The following table sets forth the volumes per day in BBLs associated with the Company's outstanding oil derivative contracts as of September 30, 2013 and the weighted average oil prices per BBL for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014				2015				2016
	Collar contracts with short puts:
	Volume (BBL)		69,000				69,000				85,000				25,000
	Price per BBL:
	Ceiling		$	120.55			$	114.05			$	98.98			$	93.3
	Floor		$	91.39			$	93.7			$	88.06			$	85
	Short put		$	74.22			$	77.61			$	73.06			$	70
	Swap contracts:
	Volume (BBL)		9,750				10,000				—				—
	Price per BBL		$	95.57			$	93.87			$	—			$	—
	Rollfactor swap contracts:
	Volume (BBL)		11,000				19,000				—				—
	NYMEX roll price (a)		$	0.85			$	0.45			$	—			$	—
	Basis swap contracts:
	Cushing to LLS index swap volume (BBL)		3,000				—				—				—
	Price per BBL (b)		$	8.53			$	—			$	—			$	—
	____________________
	(a)	Represents swaps that fix the difference between (i) each day's price per BBL of WTI for the first nearby month less (ii) the price per BBL of WTI for the second nearby NYMEX month, multiplied by .6667; plus (iii) each day's price per BBL of WTI for the first nearby month less (iv) the price per BBL of WTI for the third nearby NYMEX month, multiplied by .3333.
	(b)	Basis differential price between Cushing WTI and Louisiana Light Sweet crude ("LLS").
Schedule of NGL derivative volumes and weighted average prices	'
	The following table sets forth the volumes per day in BBLs associated with the Company's outstanding NGL derivative contracts as of September 30, 2013 and the weighted average NGL prices per BBL for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014
	Collar contracts with short puts (a):
	Volume (BBL)		1,064				1,000
	Price per BBL:
	Ceiling		$	105.28			$	109.5
	Floor		$	89.3			$	95
	Short put		$	75.2			$	80
	Collar contracts (b):
	Volume (BBL)		2,500				3,000
	Price per BBL:
	Ceiling		$	12.68			$	13.72
	Floor		$	10.5			$	10.78
	____________________
	(a)	Represent collar contracts with short puts that reduce the price volatility of natural gasoline forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
	(b)	Represent collar contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
Schedule of gas derivative volume and weighted average prices	'
	The following table sets forth the volumes per day in MMBTUs associated with the Company's outstanding gas derivative contracts as of September 30, 2013 and the weighted average gas prices per MMBTU for those contracts:
			Three Months Ending December 31,				Year Ending December 31,
			2013				2014				2015				2016
	Collar contracts with short puts:
	Volume (MMBTU)		—				115,000				285,000				20,000
	Price per MMBTU:
	Ceiling		$	—			$	4.7			$	5.07			$	5.36
	Floor		$	—			$	4			$	4			$	4
	Short put		$	—			$	3			$	3			$	3
	Collar contracts:
	Volume (MMBTU)		152,500				—				—				—
	Price per MMBTU:
	Ceiling		$	6.22			$	—			$	—			$	—
	Floor		$	4.98			$	—			$	—			$	—
	Swap contracts:
	Volume (MMBTU)		165,870				175,000				20,000				—
	Price per MMBTU		$	5.1			$	4.02			$	4.31			$	—
	Basis swap contracts:
	Volume (MMBTU) (a)		162,500				75,082				30,000				—
	Price per MMBTU		$	(0.22	)		$	(0.19	)		$	(0.18	)		$	—
	____________________
	(a)	Subsequent to September 30, 2013, the Company entered into additional basis swap contracts for 10,000 MMBTU per day of the Company's 2014 production with a negative price differential of $0.26 per MMBTU between the relevant index price and the NYMEX price.
Offsetting Asset and Liability	'
	Tabular disclosure of derivative financial instruments. All of the Company's derivatives are accounted for as non-hedge derivatives as of September 30, 2013 and December 31, 2012 and therefore all changes in the fair values of its derivative contracts are recognized as gains or losses in the earnings of the periods in which they occur. The Company classifies the fair value amounts of derivative assets and liabilities as net current or noncurrent derivative assets or net current or noncurrent derivative liabilities, whichever the case may be, by commodity and counterparty. The Company enters into derivatives under master netting arrangements, which, in an event of default, allows the Company to offset payables to and receivables from the defaulting counterparty.
	The aggregate fair value of the Company's derivative instruments reported in the consolidated balance sheets by type and counterparty, including the classification between current and noncurrent assets and liabilities, consists of the following:
	Fair Value of Derivative Instruments as of September 30, 2013
	Type		Consolidated Balance Sheet		Fair				Gross Amounts Offset in the Consolidated Balance Sheet				Net Fair Value Presented in the Consolidated Balance Sheet
			Location		Value
					(in thousands)
	Derivatives not designated as hedging instruments
	Asset Derivatives:
	Commodity price derivatives		Derivatives - current		$	117,191			$	(12,368	)		$	104,823
	Interest rate derivatives		Derivatives - current		$	9,342			$	—			$	9,342
	Commodity price derivatives		Derivatives - noncurrent		$	96,371			$	(9,968	)		86,403
	Interest rate derivatives		Derivatives - noncurrent		$	15,767			$	(15,595	)		$	172
													$	200,740
	Liability Derivatives:
	Commodity price derivatives		Derivatives - current		$	18,804			$	(12,368	)		$	6,436
	Commodity price derivatives		Derivatives - noncurrent		$	14,560			$	(9,968	)		4,592
	Interest rate derivatives		Derivatives - noncurrent		$	18,722			$	(15,595	)		$	3,127
													$	14,155
	Fair Value of Derivative Instruments as of December 31, 2012
	Type		Consolidated Balance Sheet		Fair				Gross Amounts Offset in the Consolidated Balance Sheet				Net Fair Value Presented in the Consolidated Balance Sheet
			Location		Value
					(in thousands)
	Derivatives not designated as hedging instruments
	Asset Derivatives:
	Commodity price derivatives		Derivatives - current		$	286,805			$	(7,686	)		$	279,119
	Commodity price derivatives		Derivatives - noncurrent		$	61,618			$	(6,361	)		55,257
													$	334,376
	Liability Derivatives:
	Commodity price derivatives		Derivatives - current		$	21,102			$	(7,686	)		$	13,416
	Commodity price derivatives		Derivatives - noncurrent		$	8,944			$	(6,361	)		2,583
	Interest rate derivatives		Derivatives - noncurrent		$	9,724			$	—			9,724
													$	25,723
	The Company uses credit and other financial criteria to evaluate the credit standing of, and to select, counterparties to its derivative instruments. Although the Company does not obtain collateral or otherwise secure the fair value of its derivative instruments, associated credit risk is mitigated by the Company's credit risk policies and procedures.
Schedule of derivative gains and losses recognized on statement of operations	'
	The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations:
	Derivatives Not Designated as Hedging		Location of Gain / (Loss) Recognized in		Three Months Ended								Nine Months Ended
					September 30,								September 30,
	Instruments		Earnings on Derivatives		2013				2012				2013				2012
					(in thousands)
	Commodity price derivatives		Derivative gains (losses), net		$	(108,922	)		$	(118,795	)		$	(16,926	)		$	267,806
	Interest rate derivatives		Derivative gains (losses), net		6,387				(5,199		)		16,593				(24,238		)
	Total				$	(102,535	)		$	(123,994	)		$	(333	)		$	243,568

Exploratory_Costs_Tables

Exploratory Costs (Tables)	9 Months Ended
	Sep. 30, 2013
Exploratory Cost Disclosure [Abstract]	'
Capitalized exploratory well and project activity	'
	The following table reflects the Company's capitalized exploratory well and project activity during the three and nine months ended September 30, 2013:
		Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
		(in thousands)
	Beginning capitalized exploratory costs	$	255,001		$	212,670
	Additions to exploratory costs pending the determination of proved reserves	252,884			945,001
	Reclassification due to determination of proved reserves	(168,299		)	(720,338		)
	Disposition of assets	(5,251		)	(92,955		)
	Exploratory well costs charged to exploration expense	433			(9,610		)
	Ending capitalized exploratory costs	$	334,768		$	334,768
Aging of capitalized exploratory costs and the number of projects for which exploratory costs have been capitalized	'
	The following table provides an aging, as of September 30, 2013 and December 31, 2012, of capitalized exploratory costs and the number of projects for which exploratory costs have been capitalized for a period greater than one year based on the date drilling was completed:
		September 30, 2013			December 31, 2012
		(in thousands, except project counts)
	Capitalized exploratory costs that have been suspended:
	One year or less	$	188,511		$	190,678
	More than one year	146,257			21,992
		$	334,768		$	212,670
	Number of projects with exploratory costs that have been suspended for a period greater than one year	2			1

Incentive_Plans_Tables

Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2013
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Schedule of Share Based Incentive Award Activity	'
	The following table summarizes the activity that occurred during the nine months ended September 30, 2013, for each type of share-based incentive award issued by Pioneer or Pioneer Southwest:
		Restricted		Restricted		Performance		Stock		Pioneer		Pioneer
		Stock Equity		Stock		Units		Options		Southwest		Southwest
		Awards		Liability						LTIP		LTIP
				Awards						Restricted		Phantom
										Units		Units
	Outstanding as of December 31, 2012	1,512,762		405,916		91,370		467,486		7,496		102,644
	Awards granted	433,311		250,641		94,917		—		—		32,242
	Awards vested	(509,659	)	(197,769	)	—		—		(7,496	)	(35,118	)
	Options exercised	—		—		—		(166,474	)	—		—
	Awards forfeited	(65,950	)	(29,664	)	(10,842	)	(11,085	)	—		—
	Outstanding as of September 30, 2013	1,370,464		429,124		175,445		289,927		—		99,768

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Schedule of asset retirement obligations	'
	The following table summarizes the Company's asset retirement obligation activity during the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands)
	Beginning asset retirement obligations		$	191,129		$	145,457		$	197,754		$	136,742
	Liabilities assumed in acquisitions		—			—			—			8,515
	New wells placed on production		1,234			1,251			3,682			3,662
	Changes in estimates (a)		—			48			(5,597		)	1,651
	Dispositions		—			(2,536		)	(4,310		)	(2,536		)
	Liabilities settled		(4,721		)	(4,507		)	(10,218		)	(13,249		)
	Accretion of discount		3,180			2,497			9,499			7,371
	Accretion of discount from integrated services (b)		1			23			13			77
	Ending asset retirement obligations		$	190,823		$	142,233		$	190,823		$	142,233
	_____________________
	(a)	The changes in estimates during the nine months ended September 30, 2013 are attributable to lengthening the economic lives of certain wells, which reduced the present values of the associated asset retirement obligations.
	(b)	Accretion of discount from integrated services includes Premier Silica accretion expense, which is recorded as a reduction in third-party income from vertical integration services in interest and other income in the Company's accompanying consolidated statements of operations. See Note K for more information about interest and other income.

Interest_And_Other_Income_Tabl

Interest And Other Income (Tables)	9 Months Ended
	Sep. 30, 2013
Interest and Other Income [Abstract]	'
Components of interest and other income	'
	The following table provides the components of the Company's interest and other income for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended				Nine Months Ended
			September 30,				September 30,
			2013		2012		2013			2012
			(in thousands)
	Alaskan Petroleum Production Tax credits and refunds (a)		$	12,864	$	3,979	$	38,633		$	15,825
	Equity interest in income of unconsolidated affiliate (b)		3,941		1,151		10,024			2,696
	Other income		1,554		1,373		5,119			3,608
	Deferred compensation plan income		381		204		2,363			1,727
	Interest income		81		84		256			1,400
	Income (loss) from vertical integration services (c)		2,266		3,465		(14,834		)	6,194
	Total interest and other income		$	21,087	$	10,256	$	41,561		$	31,450
	____________________
	(a)	The Company earns Alaskan Petroleum Production Tax ("PPT") credits on qualifying capital expenditures. The Company recognizes income from PPT credits when they are realized through cash refunds or as reductions in production and ad valorem taxes if realizable as offsets to PPT expense.
	(b)	The Company, along with its joint venture partner, formed EFS Midstream LLC ("EFS Midstream") in 2010 to operate gathering facilities in the Eagle Ford Shale area. The Company accounts for its investment in EFS Midstream using the equity method. EFS Midstream is providing gathering, treating and transportation services for the Company during a 20-year contractual term.
	(c)	Income (loss) from vertical integration services represent net margins that result from Company-provided fracture stimulation, drilling and related service operations, which are ancillary to and supportive of the Company's oil and gas joint operating activities, and do not represent intercompany transactions. For the three and nine months ended September 30, 2013, these net margins include $103.1 million and $206.3 million of gross vertical integration revenues, respectively, and $100.8 million and $221.1 million of total vertical integration costs and expenses, respectively. For the same periods in 2012, these net margins include $61.9 million and $223.6 million of gross vertical integration revenues, respectively, and $58.4 million and $217.4 million of total vertical integration costs and expenses, respectively.

Other_Expense_Tables

Other Expense (Tables)	9 Months Ended
	Sep. 30, 2013
Other Expense [Abstract]	'
Schedule of components of other expense	'
	The following table provides the components of the Company's other expense for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended				Nine Months Ended
			September 30,				September 30,
			2013		2012		2013		2012
			(in thousands)
	Transportation commitment charge (a)		$	13,482	$	9,694	$	31,228	$	27,374
	Other		2,825		2,586		11,138		12,709
	Above market and idle drilling and well services equipment rates (b)		1,293		12,808		9,744		23,553
	Contingency and environmental accrual adjustments		4,701		70		6,782		772
	Inventory impairment (c)		2,646		46		5,096		6,093
	Terminated drilling rig contract charges (d)		—		6,807		1,019		15,768
	Total other expense		$	24,947	$	32,011	$	65,007	$	86,269
	____________________
	(a)	Primarily represents firm transportation payments on excess pipeline capacity commitments.
	(b)	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that are above current market rates and idle drilling rig fees, neither of which are charged to joint operations.
	(c)	Represents valuation charges on excess or damaged materials and supplies inventories.
	(d)	Primarily represents charges to terminate drilling rig contracts that are not required to meet planned activities.

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income tax (provisions) benefits attributable to income from continuing operations	'
	The Company's income tax benefits or provisions attributable to income from continuing operations consisted of the following for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(in thousands)
	Current	$	8,341		$	8,275		$	(9,279	)	$	(7,051	)
	Deferred	(66,574		)	(18,889		)	(300,312		)	(76,180		)
	Income tax provision	$	(58,233	)	$	(10,614	)	$	(309,591	)	$	(83,231	)

Net_Income_Loss_Per_Share_Tabl

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Reconciliation of earnings attributable to common stockholders, basic and diluted	'
	The following tables reconcile the Company's net income (loss) attributable to common stockholders to basic net income (loss) attributable to common stockholders and diluted net income (loss) attributable to common stockholders for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended September 30, 2013										Nine Months Ended September 30, 2013
			Continuing				Discontinued			Total			Continuing			Discontinued			Total
			Operations				Operations						Operations			Operations
			(in thousands)
	Net income (loss) attributable to common stockholders		$	91,125			$	—		$	91,125		$	529,516		$	(465	)	$	529,051
	Participating basic earnings		(1,239		)		—			(1,239		)	(6,729		)	—			(6,729		)
	Basic net income (loss) attributable to common stockholders		89,886				—			89,886			522,787			(465		)	522,322
	Reallocation of participating earnings		3				—			3			102			—			102
	Diluted income (loss) attributable to common stockholders		$	89,889			$	—		$	89,889		$	522,889		$	(465	)	$	522,424
			Three Months Ended September 30, 2012										Nine Months Ended September 30, 2012
			Continuing				Discontinued			Total			Continuing			Discontinued			Total
			Operations				Operations						Operations			Operations
			(in thousands)
	Net income (loss) attributable to common stockholders		$	(13,071	)		$	32,295		$	19,224		$	108,444		$	55,007		$	163,451
	Participating basic earnings		—				(357		)	(357		)	(1,658		)	(841		)	(2,499		)
	Basic net income (loss) attributable to common stockholders		(13,071		)		31,938			18,867			106,786			54,166			160,952
	Reallocation of participating earnings		—				—			—			89			45			134
	Diluted income (loss) attributable to common stockholders		$	(13,071	)		$	31,938		$	18,867		$	106,875		$	54,211		$	161,086
Reconciliation Of Basic To Diluted Weighted Average Common Shares Outstanding	'
	The following table is a reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three and nine months ended September 30, 2013 and 2012:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013		2012
			(in thousands)
	Weighted average common shares outstanding:
	Basic		138,586			123,111			135,057		122,874
	Dilutive common stock options (a)		128			—			141		196
	Convertible Senior Notes dilution (a)		—			—			1,453		2,866
	Contingently issuable performance unit shares (a)		232			—			184		175
	Diluted		138,946			123,111			136,835		126,111
	____________________
	(a)	The following common share equivalents were excluded from the weighted average diluted shares for the three months ended September 30, 2012 because they would have been anti-dilutive to the loss recorded for the period: 179,449 outstanding options to purchase the Company's common stock, 184,545 common shares attributable to unvested performance units and 3,311,845 common shares issuable if holders of the Company's 2.875% Convertible Senior Notes had exercised their conversion rights (see Note G). Options to purchase 185,722 shares of the Company's common stock were excluded from the diluted income per share calculations for the nine months ended September 30, 2012 because they would have been anti-dilutive to the calculation. For the nine months ended September 30, 2013, options to purchase 34,842 shares of the Company's common stock were excluded from the diluted income per share calculation because they would have been anti-dilutive to the calculation.

Basis_Of_Presentation_Basis_of

Basis Of Presentation Basis of Presentation (Narrative) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Stock Issued During Period, Shares, New Issues	10,350	'	'
Proceeds from Issuance of Common Stock	$1,280,916	$0	'
Noncontrolling interests in consolidating subsidiaries	181,544	'	177,954
Pioneer Southwest [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Noncontrolling interests in consolidating subsidiaries	$167,900	'	'
Pioneer Southwest [Member] | General Partner Interest [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Noncontrolling Interest, Ownership Percentage by Parent	0.10%	'	'
Pioneer Southwest [Member] | Limited Partner Interest [Member]	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Noncontrolling Interest, Ownership Percentage by Parent	52.40%	'	'

Acquisitions_and_Divestitures_

Acquisitions and Divestitures (Narrative) (Details) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Sep. 30, 2013

Mar. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Mar. 31, 2012

Dec. 31, 2012

Mar. 31, 2012

Dec. 31, 2012

Nov. 06, 2013

Sep. 30, 2013

Sep. 30, 2013

Wolfcamp [Member]

Wolfcamp [Member]

West Panhandle [Member]

Barnett Shale Field [Member]

Cook Inlet [Member]

Eagle Ford Shale [Member]

Pioneer South Africa [Member]

Pioneer South Africa [Member]

Premier Silica [Member]

Pioneer Southwest [Member]

Pioneer Southwest [Member]

Limited Partner Interest [Member]

Rate

Pioneer Southwest [Member]

Rate

Acquisitions and Divestitures [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net

'

'

'

'

'

'

'

'

'

'

'

'

'

$297,100,000

'

'

'

Joint Venture Investment Ownership Percentage

'

'

'

'

'

40.00%

'

'

'

'

'

'

'

'

'

'

'

Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds

'

'

'

'

'

'

1,800,000,000

'

'

'

'

'

60,000,000

'

'

'

'

Proceeds from Sale of Productive Assets

'

'

685,188,000

92,473,000

'

621,200,000

'

38,100,000

11,600,000

10,100,000

54,700,000

'

'

'

'

'

'

Gain (loss) on disposition of assets, net

-487,000

12,848,000

214,917,000

57,584,000

'

179,700,000

'

22,400,000

8,700,000

12,600,000

42,600,000

28,600,000

'

'

'

'

'

Goodwill

279,687,000

'

279,687,000

'

298,142,000

18,500,000

'

'

'

'

'

'

'

'

'

'

'

Maximum Payments From Related Party For Exploration Drilling And Completion Costs

'

'

'

'

'

1,200,000,000

'

'

'

'

'

'

'

'

'

'

'

Payments From Related Party For Exploration Drilling And Completion Costs Percent

'

'

'

'

'

75.00%

'

'

'

'

'

'

'

'

'

'

'

Proceeds from Divestiture of Interest in Consolidated Subsidiaries

'

'

'

'

'

'

'

'

'

'

'

15,900,000

'

'

'

'

'

Oil And Gas Revenue From Discontinued Operations

'

38,100,000

'

77,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax

'

$37,200,000

'

$71,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Share Per Unit Exchange Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.2325

'

Maximum Distribution Made to Limited Partner, Distributions Declared, Per Unit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.52

'

Distribution Made to Member or Limited Partner, Distributions Declared, Per Unit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.52

'

'

Noncontrolling Interest, Ownership Percentage by Parent

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

52.40%

Fair_Value_Measurements_Schedu

Fair Value Measurements (Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Trading Securities, Fair Value Disclosure	$296
Deferred Compensation Plan Assets	59,939
Assets, Fair Value Disclosure	260,975
Liabilities, Fair Value Disclosure	14,155
Recurring Measurements, (Fair Value, Total)	246,820
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Trading Securities, Fair Value Disclosure	149
Deferred Compensation Plan Assets	59,939
Assets, Fair Value Disclosure	60,088
Liabilities, Fair Value Disclosure	0
Recurring Measurements, (Fair Value, Total)	60,088
Significant Other Observable Inputs (Level 2) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Trading Securities, Fair Value Disclosure	147
Deferred Compensation Plan Assets	0
Assets, Fair Value Disclosure	200,887
Liabilities, Fair Value Disclosure	14,155
Recurring Measurements, (Fair Value, Total)	186,732
Fair Value, Inputs, Level 3 [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Trading Securities, Fair Value Disclosure	0
Deferred Compensation Plan Assets	0
Assets, Fair Value Disclosure	0
Liabilities, Fair Value Disclosure	0
Recurring Measurements, (Fair Value, Total)	0
Interest Rate Derivatives [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	9,514
Derivative Liability, Fair Value, Net	3,127
Interest Rate Derivatives [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	0
Derivative Liability, Fair Value, Net	0
Interest Rate Derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	9,514
Derivative Liability, Fair Value, Net	3,127
Interest Rate Derivatives [Member] | Fair Value, Inputs, Level 3 [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	0
Derivative Liability, Fair Value, Net	0
Commodity Derivatives [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	191,226
Derivative Liability, Fair Value, Net	11,028
Commodity Derivatives [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	0
Derivative Liability, Fair Value, Net	0
Commodity Derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	191,226
Derivative Liability, Fair Value, Net	11,028
Commodity Derivatives [Member] | Fair Value, Inputs, Level 3 [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Derivative Asset, Fair Value, Net	0
Derivative Liability, Fair Value, Net	$0

Fair_Value_Measurements_Schedu1

Fair Value Measurements (Schedule Of Carrying Values And Financial Instruments Not Carried At Fair Value) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Long-term Debt Element	$2,851,212	$3,721,193
Carrying Value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Long-term Debt Element	2,851,212	3,721,193
Fair Value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Long-term Debt Element	$3,247,459	$4,555,770

Fair_Value_Measurements_Nonrec

Fair Value Measurements Nonrecurring Fair Value Measurements (Details) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
NonRecurring Fair Value Disclosures [Abstract]	'	'	'	'	'
Impairment of oil and gas properties	$0	$0	'	$0	$444,880
Management oil price outlook	'	'	87.09	'	'
Management gas price outlook	'	'	4.64	'	'

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended
	Jun. 30, 2013	Sep. 30, 2013
		July 15, 2022 Interest Rate Swaps [Member]
Trading Activity, Gains and Losses, Net [Line Items]	'	'
Derivative, Fixed Interest Rate	3.21%	3.95%
Notional amount of debt	$250,000,000	$400,000,000
Proceeds from Termination of Interest Rate Derivatives	$482,000	'
Derivative, Average Variable Interest Rate	'	1.11%

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Schedule Of Oil Derivative Contracts Volume And Weighted Average Prices) (Details)	9 Months Ended
	Sep. 30, 2013
Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
NYMEX swap multiple, second nearby month	0.6667
NYMEX swap multiple, third nearby month	0.3333
Oil contracts [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	69,000
Oil contracts [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	69,000
Oil contracts [Member] | Two Thousand Fifteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	85,000
Oil contracts [Member] | Two Thousand Sixteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	25,000
Oil contracts [Member] | Two Thousand Thirteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	9,750
Oil contracts [Member] | Two Thousand Fourteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	10,000
Oil contracts [Member] | Two Thousand Fifteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | Two Thousand Sixteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | Two Thousand Thirteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	11,000
Oil contracts [Member] | Two Thousand Fourteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	19,000
Oil contracts [Member] | Two Thousand Fifteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | Two Thousand Sixteen Rollfactor Swap Contracts [Member] [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | 2013 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	3,000
Oil contracts [Member] | 2014 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | 2015 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts [Member] | 2016 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Average daily oil production derivative barrels per day	0
Oil contracts, price per bbl [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	120.55
Derivative, Average Floor Price	91.39
Oil contracts, price per bbl [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	74.22
Oil contracts, price per bbl [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	114.05
Derivative, Average Floor Price	93.7
Oil contracts, price per bbl [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	77.61
Oil contracts, price per bbl [Member] | Two Thousand Fifteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	98.98
Derivative, Average Floor Price	88.06
Oil contracts, price per bbl [Member] | Two Thousand Fifteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	73.06
Oil contracts, price per bbl [Member] | Two Thousand Sixteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	93.3
Derivative, Average Floor Price	85
Oil contracts, price per bbl [Member] | Two Thousand Sixteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	70
Oil contracts, price per bbl [Member] | Two Thousand Thirteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	95.57
Oil contracts, price per bbl [Member] | Two Thousand Fourteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	93.87
Oil contracts, price per bbl [Member] | Two Thousand Fifteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	0
Oil contracts, price per bbl [Member] | Two Thousand Sixteen Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	0
Oil contracts, price per bbl [Member] | Two Thousand Thirteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0.85	[1]
Oil contracts, price per bbl [Member] | Two Thousand Fourteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0.45	[1]
Oil contracts, price per bbl [Member] | Two Thousand Fifteen Rollfactor Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0	[1]
Oil contracts, price per bbl [Member] | Two Thousand Sixteen Rollfactor Swap Contracts [Member] [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0	[1]
Oil contracts, price per bbl [Member] | 2013 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	8.53	[2]
Oil contracts, price per bbl [Member] | 2014 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0	[2]
Oil contracts, price per bbl [Member] | 2015 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0	[2]
Oil contracts, price per bbl [Member] | 2016 Cushing LLS Basis Swap Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	0	[2]
[1]	Represents swaps that fix the difference between (i)B each day's price per BBL of WTI for the first nearby month less (ii)B the price per BBL of WTI for the second nearby NYMEX month, multiplied by .6667; plus (iii)B each day's price per BBL of WTI for the first nearby month less (iv)B the price per BBL of WTI for the third nearby NYMEX month, multiplied by .3333.
[2]	Basis differential price between Cushing WTI and Louisiana Light Sweet crude ("LLS").

Derivative_Financial_Instrumen4

Derivative Financial Instruments Derivative Financial Instruments (Schedule of NGL Derivative Contracts Volume and Weighted Average Prices) (Details)	Sep. 30, 2013
	bbl
NGL contract, in BBLS [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average Daily NGL Production Derivative Barrels Per Day	1,064	[1]
NGL contract, in BBLS [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Average Daily NGL Production Derivative Barrels Per Day	1,000	[1]
NGL contract, in BBLS [Member] | Two Thousand Thirteen Collar Contracts [Member]	'
Derivative [Line Items]	'
Average Daily NGL Production Derivative Barrels Per Day	2,500	[2]
NGL contract, in BBLS [Member] | Two Thousand Fourteen Collar Contracts [Member]	'
Derivative [Line Items]	'
Average Daily NGL Production Derivative Barrels Per Day	3,000	[2]
NGL contracts, price per BBL [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	105.28	[1]
Derivative, Average Floor Price	89.3	[1]
NGL contracts, price per BBL [Member] | Two Thousand Thirteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	75.2	[1]
NGL contracts, price per BBL [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	109.5	[1]
Derivative, Average Floor Price	95	[1]
NGL contracts, price per BBL [Member] | Two Thousand Fourteen Collar Contracts With Short Puts [Member] | Short Put [Member]	'
Derivative [Line Items]	'
Derivative, Notional Amount, Price Per Unit	80	[1]
NGL contracts, price per BBL [Member] | Two Thousand Thirteen Collar Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	12.68	[2]
Derivative, Average Floor Price	10.5	[2]
NGL contracts, price per BBL [Member] | Two Thousand Fourteen Collar Contracts [Member]	'
Derivative [Line Items]	'
Derivative, Average Cap Price	13.72	[2]
Derivative, Average Floor Price	10.78	[2]
[1]	Represent collar contracts with short puts that reduce the price volatility of natural gasoline forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
[2]	Represent collar contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.

Derivative_Financial_Instrumen5

Derivative Financial Instruments Derivative Financial Instruments (Schedule of Gas Derivative Contracts Volume and Weighted Average Prices) (Details)	Nov. 06, 2013		Sep. 30, 2013
	MMBTU		MMBTU
Two Thousand Thirteen Collar Contracts With Short Puts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Thirteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		0
Derivative, Average Floor Price	'		0
Two Thousand Thirteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member] | Short Put [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Notional Amount, Price Per Unit	'		0
Two Thousand Fourteen Collar Contracts With Short Puts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		115,000
Two Thousand Fourteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		4.7
Derivative, Average Floor Price	'		4
Two Thousand Fourteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member] | Short Put [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Notional Amount, Price Per Unit	'		3
Two Thousand Fifteen Collar Contracts With Short Puts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		285,000
Two Thousand Fifteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		5.07
Derivative, Average Floor Price	'		4
Two Thousand Fifteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member] | Short Put [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Notional Amount, Price Per Unit	'		3
Two Thousand Sixteen Collar Contracts With Short Puts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		20,000
Two Thousand Sixteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		5.36
Derivative, Average Floor Price	'		4
Two Thousand Sixteen Collar Contracts With Short Puts [Member] | Gas contracts, price per MMBTU [Member] | Short Put [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Notional Amount, Price Per Unit	'		3
Two Thousand Thirteen Collar Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		152,500
Two Thousand Thirteen Collar Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		6.22
Derivative, Average Floor Price	'		4.98
Two Thousand Fourteen Collar Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Fourteen Collar Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		0
Derivative, Average Floor Price	'		0
Two Thousand Fifteen Collar Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Fifteen Collar Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		0
Derivative, Average Floor Price	'		0
Two Thousand Sixteen Collar Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Sixteen Collar Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Average Cap Price	'		0
Derivative, Average Floor Price	'		0
Two Thousand Thirteen Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		165,870
Two Thousand Thirteen Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		5.1
Two Thousand Fourteen Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		175,000
Two Thousand Fourteen Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		4.02
Two Thousand Fifteen Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		20,000
Two Thousand Fifteen Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		4.31
Two Thousand Sixteen Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Sixteen Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		0
Two Thousand And Thirteen Basis Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		162,500
Two Thousand And Thirteen Basis Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		-0.22
Two Thousand Fourteen Basis Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	10,000	[1]	75,082	[1]
Two Thousand Fourteen Basis Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	-0.26	[1]	-0.19	[1]
Two Thousand Fifteen Basis Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		30,000
Two Thousand Fifteen Basis Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		-0.18
Two Thousand Sixteen Basis Swap Contracts [Member] | Gas contracts, in MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Average Daily Gas Production Derivatives Volume per Day	'		0
Two Thousand Sixteen Basis Swap Contracts [Member] | Gas contracts, price per MMBTU [Member]	'		'
Derivative [Line Items]	'		'
Derivative, Swap Type, Fixed Price	'		0
[1]	Subsequent to September 30, 2013, the Company entered into additional basis swap contracts for 10,000 MMBTU per day of the Company's 2014 production with a negative price differential of $0.26 per MMBTU between the relevant index price and the NYMEX price.

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Schedule Of Derivative Instruments) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Derivative Assets, Current	$114,166	$279,119
Derivative Assets, Noncurrent	86,574	55,257
Derivative Liabilities, Current	6,436	13,416
Derivative Liabilities, Noncurrent	7,719	12,307
Not Designated as Hedging Instrument [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Fair Value, Net	200,740	334,376
Derivative Liability, Fair Value, Net	14,155	25,723
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Current [Member]	'	'
Derivative [Line Items]	'	'
Total derivatives, Asset, Gross	117,191	286,805
Total derivatives, Liability. Gross	18,804	21,102
Derivative Assets Offset In Balance Sheet	-12,368	-7,686
Derivative Liabilities Offset In Balance Sheet	-12,368	-7,686
Derivative Assets, Current	104,823	279,119
Derivative Liabilities, Current	6,436	13,416
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Noncurrent [Member]	'	'
Derivative [Line Items]	'	'
Total derivatives, Asset, Gross	96,371	61,618
Total derivatives, Liability. Gross	14,560	8,944
Derivative Assets Offset In Balance Sheet	-9,968	-6,361
Derivative Liabilities Offset In Balance Sheet	-9,968	-6,361
Derivative Assets, Noncurrent	86,403	55,257
Derivative Liabilities, Noncurrent	4,592	2,583
Not Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Derivatives - Current [Member]	'	'
Derivative [Line Items]	'	'
Total derivatives, Asset, Gross	9,342	'
Derivative Assets Offset In Balance Sheet	0	'
Derivative Assets, Current	9,342	'
Not Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Derivatives - Noncurrent [Member]	'	'
Derivative [Line Items]	'	'
Total derivatives, Asset, Gross	15,767	'
Total derivatives, Liability. Gross	18,722	9,724
Derivative Assets Offset In Balance Sheet	-15,595	'
Derivative Liabilities Offset In Balance Sheet	-15,595	0
Derivative Assets, Noncurrent	172	'
Derivative Liabilities, Noncurrent	$3,127	$9,724

Derivative_Financial_Instrumen7

Derivative Financial Instruments (Schedule Of Derivative Obligations Under Terminated Hedge Arrangements) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative [Line Items]	'	'	'	'
Derivative gains (losses), net	($102,535)	($123,994)	($333)	$243,568
Commodity Price Derivatives [Member] | Derivative Gains, Net [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivative gains (losses), net	-108,922	-118,795	-16,926	267,806
Interest Rate Derivatives [Member] | Derivative Gains, Net [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivative gains (losses), net	$6,387	($5,199)	$16,593	($24,238)

Exploratory_Costs_Schedule_Of_

Exploratory Costs (Schedule Of Capitalized Exploratory Well And Project Activity) (Details) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Exploratory Cost Disclosure [Abstract]	'	'	'
Beginning capitalized exploratory costs	$255,001	$212,670	'
Additions to exploratory costs pending the determination of proved reserves	252,884	945,001	'
Reclassification due to determination of proved reserves	-168,299	-720,338	'
Capitalized Exploratory Well Cost Assets Disposition	-5,251	-92,955	'
Exploratory well costs charged to exploration expense	433	-9,610	'
Ending capitalized exploratory costs	334,768	334,768	'
Capitalized exploratory costs that have been suspended, One year or less	188,511	188,511	190,678
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	$146,257	$146,257	$21,992
Number of projects with exploratory costs that have been suspended for a period greater than one year	2	2	1

Exploratory_Costs_Exploratory_

Exploratory Costs Exploratory Costs (Narrative) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]	'	'
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	$146,257	$21,992
Oooguruk [Member]	'	'
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]	'	'
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	30,800	22,000
Nuna [Member]	'	'
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]	'	'
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	$115,500	'

LongTerm_Debt_Details

Long-Term Debt (Details) (USD $)	9 Months Ended
Share data in Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
PXD Credit Facility [Member]	'	'
Debt Instrument [Line Items]	'	'
Maximum Borrowing Capacity	$1,500,000,000	'
Pioneer Southwest Credit Facility [Member]	'	'
Debt Instrument [Line Items]	'	'
Maximum Borrowing Capacity	300,000,000	'
Outstanding borrowing	201,000,000	'
Unused borrowing capacity	68,600,000	'
2.875% Convertible Senior Notes Due 2038 [Member]	'	'
Debt Instrument [Line Items]	'	'
Convertible Debt	'	479,900,000
Senior notes, interest rate, percentage	'	2.88%
Principal amount of notes tendered for conversion	479,100,000	'
Cash Paid To Conversion Of Convertible Senior Notes	479,100,000	'
Shares issued for conversion of debt	4.4	'
Cash Paid To Redeem Convertible Debt	$845,000	'

Incentive_Plans_Incentive_Plan

Incentive Plans Incentive Plans (Stock-based compensation) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Allocated Share-based Compensation Expense	$32.50	$22.80	$85.30	$66	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	178.1	'	178.1	'	'
Share Based Compensation Arrangement By Share Based Payment Award Liability	56.6	'	56.6	'	'
Postretirement benefit obligation	8.3	'	8.3	'	9.7
Restricted Stock Equity Awards [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Amount Of Liabilities Attributable To Liability Awards Included In Accounts Payable	$24.50	'	$24.50	'	$18.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,370,464	'	1,370,464	'	1,512,762
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	433,311	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	-509,659	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	-65,950	'	'
Restricted Stock Liability Awards [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	429,124	'	429,124	'	405,916
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	250,641	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	-197,769	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	-29,664	'	'
Performance Units [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	175,445	'	175,445	'	91,370
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	94,917	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	-10,842	'	'
Stock Options [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	289,927	'	289,927	'	467,486
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	-166,474	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	-11,085	'	'
Pioneer Southwest Ltip Restricted Units [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	0	'	0	'	7,496
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	-7,496	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	0	'	'
Pioneer Southwest Ltip Phantom Units [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	99,768	'	99,768	'	102,644
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	'	'	32,242	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	'	'	-35,118	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	'	'	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	'	'	0	'	'

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Asset Retirement Obligation [Abstract]	'		'		'		'		'
Beginning asset retirement obligations	$191,129,000		$145,457,000		$197,754,000		$136,742,000		'
AssetRetirementObligationLiabilitiesAcquiredInBusinessCombination	0		0		0		8,515,000		'
Asset Retirement Obligation, Liabilities Incurred	1,234,000		1,251,000		3,682,000		3,662,000		'
Changes in estimates	0		48,000	[1]	-5,597,000		1,651,000		'
Disposition of wells	0		-2,536,000		-4,310,000		-2,536,000		'
Liabilities settled	-4,721,000		-4,507,000		-10,218,000		-13,249,000		'
Accretion of discount from continuing operations	3,180,000		2,497,000		9,499,000		7,371,000		'
Accretion of discount from integrated services	1,000	[2]	23,000	[2]	13,000	[2]	77,000	[2]	'
Ending asset retirement obligations	190,823,000		142,233,000		190,823,000		142,233,000		'
Asset retirement obligations, current portions	$13,400,000		'		$13,400,000		'		$13,300,000
[1]	The changes in estimates during the nine months ended September 30, 2013 are attributable to lengthening the economic lives of certain wells, which reduced the present values of the associated asset retirement obligations.
[2]	Accretion of discount from integrated services includes Premier Silica accretion expense, which is recorded as a reduction in third-party income from vertical integration services in interest and other income in the Company's accompanying consolidated statements of operations. See Note K for more information about interest and other income.

Interest_And_Other_Income_Comp

Interest And Other Income (Components Of Interest And Other Income) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Interest and Other Income [Abstract]	'		'		'		'
Alaskan Petroleum Production Tax credits and refunds	$12,864,000	[1]	$3,979,000	[1]	$38,633,000	[1]	$15,825,000	[1]
Equity interest in income of unconsolidated affiliate	3,941,000	[2]	1,151,000	[2]	10,024,000	[2]	2,696,000	[2]
Other income	1,554,000		1,373,000		5,119,000		3,608,000
Deferred compensation plan income	381,000		204,000		2,363,000		1,727,000
Interest income	81,000		84,000		256,000		1,400,000
Third-party income from vertical integration services	2,266,000	[3]	3,465,000	[3]	-14,834,000	[3]	6,194,000	[3]
Total interest and other income	21,087,000		10,256,000		41,561,000		31,450,000
GrossRevenuesIncludedInThirdPartyIncomeFromVerticalIntegrationServices	103,100,000		61,900,000		206,300,000		223,600,000
GrossExpensesIncludedInThirdPartyIncomeFromVerticalIntegrationServices	$100,800,000		$58,400,000		$221,100,000		$217,400,000
[1]	The Company earns Alaskan Petroleum Production Tax ("PPT") credits on qualifying capital expenditures. The Company recognizes income from PPT credits when they are realized through cash refunds or as reductions in production and ad valorem taxes if realizable as offsets to PPT expense.
[2]	The Company, along with its joint venture partner, formed EFS Midstream LLC ("EFS Midstream") in 2010 to operate gathering facilities in the Eagle Ford Shale area. The Company accounts for its investment in EFS Midstream using the equity method. EFS Midstream is providing gathering, treating and transportation services for the Company during a 20-year contractual term.
[3]	Income (loss) from vertical integration services represent net margins that result from Company-provided fracture stimulation, drilling and related service operations, which are ancillary to and supportive of the Company's oil and gas joint operating activities, and do not represent intercompany transactions. For the three and nine months ended September 30, 2013, these net margins include $103.1 million and $206.3 million of gross vertical integration revenues, respectively, and $100.8 million and $221.1 million of total vertical integration costs and expenses, respectively. For the same periods in 2012, these net margins include $61.9 million and $223.6 million of gross vertical integration revenues, respectively, and $58.4 million and $217.4 million of total vertical integration costs and expenses, respectively.

Other_Expense_Schedule_Of_Comp

Other Expense (Schedule Of Components Of Other Expense) (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Other Expense [Abstract]	'		'		'		'
Transportation commitment charges	$13,482	[1]	$9,694	[1]	$31,228	[1]	$27,374	[1]
Other	2,825		2,586		11,138		12,709
Above market drilling rig rates	1,293	[2]	12,808	[2]	9,744	[2]	23,553	[2]
Contingency and environmental accrual adjustments	4,701		70		6,782		772
Inventory valuation charges	2,646	[3]	46	[3]	5,096	[3]	6,093	[3]
Terminated drilling rig contract charges	0	[4]	6,807	[4]	1,019	[4]	15,768	[4]
Total other expense	$24,947		$32,011		$65,007		$86,269
[1]	Primarily represents firm transportation payments on excess pipeline capacity commitments.
[2]	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that are above current market rates and idle drilling rig fees, neither of which are charged to joint operations.
[3]	Represents valuation charges on excess or damaged materials and supplies inventories.
[4]	Primarily represents charges to terminate drilling rig contracts that are not required to meet planned activities.

Income_Taxes_Schedule_Of_Incom

Income Taxes (Schedule Of Income Tax (Provisions) Benefits Attributable To Income From Continuing Operations) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Current Income Tax (Expense) Benefit	$8,341,000	$8,275,000	($9,279,000)	($7,051,000)
Deferred income tax (provision) benefit	-66,574,000	-18,889,000	-300,312,000	-76,180,000
Income tax (provision) benefit	-58,233,000	-10,614,000	-309,591,000	-83,231,000
Effective Tax Rate	39.00%	-432.00%	37.00%	43.00%
Statutory Tax Rate	'	'	35.00%	'
Unrecognized Tax Benefits	$21,200,000	'	$21,200,000	'

Net_Income_Loss_Per_Share_Reco

Net Income (Loss) Per Share (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Operating Activities Segment [Line Items]	'	'	'	'
Income (loss) from continuing operations attributable to parent	$91,125	($13,071)	$529,516	$108,444
Income (loss) from discontinued operations, net of tax, attributable to parent	0	32,295	-465	55,007
Income (loss) as reported	91,125	19,224	529,051	163,451
Participating basic earnings	-1,239	-357	-6,729	-2,499
Basic income attributable to common stockholders	89,886	18,867	522,322	160,952
Reallocation of participating earnings	3	0	102	134
Diluted income attributable to common stockholders	89,889	18,867	522,424	161,086
Continuing Operations [Member]	'	'	'	'
Statement Operating Activities Segment [Line Items]	'	'	'	'
Income (loss) from continuing operations attributable to parent	91,125	-13,071	529,516	108,444
Participating basic earnings	-1,239	0	-6,729	-1,658
Basic income attributable to common stockholders	89,886	-13,071	522,787	106,786
Reallocation of participating earnings	3	0	102	89
Diluted income attributable to common stockholders	89,889	-13,071	522,889	106,875
Discontinued Operations [Member]	'	'	'	'
Statement Operating Activities Segment [Line Items]	'	'	'	'
Income (loss) from discontinued operations, net of tax, attributable to parent	0	32,295	-465	55,007
Participating basic earnings	0	-357	0	-841
Basic income attributable to common stockholders	0	31,938	-465	54,166
Reallocation of participating earnings	0	0	0	45
Diluted income attributable to common stockholders	$0	$31,938	($465)	$54,211

Net_Income_Loss_Per_Share_Reco1

Net Income (Loss) Per Share (Reconciliation Of Basic To Diluted Weighted Average Common Shares Outstanding) (Details)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]	'		'		'		'
Basic	138,586,000		123,111,000		135,057,000		122,874,000
Dilutive common stock options	128,000	[1]	0	[1]	141,000	[1]	196,000	[1]
Convertible senior notes dilution	0	[1]	0	[1]	1,453,000	[1]	2,866,000	[1]
Contingently issuable performance unit shares	232,000	[1]	0	[1]	184,000	[1]	175,000	[1]
Diluted	138,946,000		123,111,000		136,835,000		126,111,000
Stock Options [Member]	'		'		'		'
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]	'		'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	'		179,449		34,842		185,722
Unvested Performance units [Member]	'		'		'		'
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]	'		'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	'		184,545		'		'
Conversion rights [Member]	'		'		'		'
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]	'		'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	'		3,311,845		'		'
[1]	The following common share equivalents were excluded from the weighted average diluted shares for the three months ended September 30, 2012 because they would have been anti-dilutive to the loss recorded for the period: 179,449 outstanding options to purchase the Company's common stock, 184,545 common shares attributable to unvested performance units and 3,311,845 common shares issuable if holders of the Company's 2.875% Convertible Senior Notes had exercised their conversion rights (see Note G). Options to purchase 185,722 shares of the Company's common stock were excluded from the diluted income per share calculations for the nine months ended September 30, 2012 because they would have been anti-dilutive to the calculation. For the nine months ended September 30, 2013, options to purchase 34,842 shares of the Company's common stock were excluded from the diluted income per share calculation because they would have been anti-dilutive to the calculation.

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Nov. 06, 2013	Nov. 06, 2013	Sep. 30, 2013
					Pioneer Alaska [Member]	Pioneer Southwest [Member]	Pioneer Southwest [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'	'
Distribution Made to Member or Limited Partner, Distributions Declared, Per Unit	'	'	'	'	'	$0.52	'
Distribution Made to Member or Limited Partner, Cash Distributions Declared	'	'	'	'	'	$18,600,000	'
Share Per Unit Exchange Ratio	'	'	'	'	'	'	0.2325
Proceeds from Sale of Productive Assets	'	'	685,188,000	92,473,000	550,000,000	'	'
Gain (loss) on disposition of assets, net	$487,000	($12,848,000)	($214,917,000)	($57,584,000)	($350,000,000)	'	'