Pioneer Natural Resources (PXD) 10-K19 Feb 152014 FY Annual reportFinancial data

Company Profile

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
Document And Entity Information (USD $)	Dec. 31, 2014	Feb. 13, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	Pioneer Natural Resources Company
Trading Symbol	PXD
Entity Central Index Key	1038357
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		148,963,753
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$32,612,539,563

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$1,025	$393
Accounts receivable:
Trade, net	436	431
Due from affiliates	4	3
Income taxes receivable	23	5
Inventories	241	220
Prepaid expenses	15	16
Assets held for sale	0	584
Other current assets:
Derivatives	578	76
Other	37	2
Total current assets	2,359	1,730
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	15,662	13,406
Unproved properties	159	123
Accumulated depletion, depreciation and amortization	-5,431	-4,903
Total property, plant and equipment	10,390	8,626
Goodwill	272	274
Other property and equipment, net	1,391	1,224
Other assets:
Investment in unconsolidated affiliate	239	225
Derivatives	181	91
Other, net	94	124
Assets, Total	14,926	12,294
Accounts payable:
Trade	1,197	910
Due to affiliates	123	150
Interest payable	40	62
Income taxes payable	1	0
Deferred income taxes	161	19
Liabilities held for sale	0	39
Other current liabilities:
Derivatives	3	12
Other	55	58
Total current liabilities	1,580	1,250
Long-term debt	2,665	2,653
Derivatives	2	10
Deferred income taxes	1,803	1,473
Other liabilities	287	293
Stockholders' equity:
Common stock, $.01 par value	2	1
Additional paid-in capital	6,167	5,080
Treasury stock, at cost	-171	-144
Retained earnings	2,583	1,665
Total stockholders' equity attributable to common stockholders	8,581	6,602
Noncontrolling interest in consolidating subsidiaries	8	13
Total stockholders' equity	8,589	6,615
Liabilities and Stockholders' Equity, Total	$14,926	$12,294

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
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	152,000,000	146,000,000
Treasury stock, shares	3,000,000	3,000,000

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Revenues and other income:
Oil and gas	$3,599	$3,088		$2,512
Sales of purchased oil and gas	726	334		122
Interest and other	9	17		-1
Derivative gains, net	712	4		330
Gain on disposition of assets, net	9	209		46
Revenues	5,055	3,652		3,009
Costs and expenses:
Oil and gas production	693	588		532
Production and ad valorem taxes	220	192		169
Depletion, depreciation and amortization	1,047	889		689
Purchased oil and gas	703	336		120
Impairment of oil and gas properties	0	1,495		0
Exploration and abandonments	177	97		97
General and administrative	333	296		244
Accretion of discount on asset retirement obligations	12	12		8
Interest	184	184		204
Other	89	137		114
Costs and expenses, Total	3,458	4,226		2,177
Income (loss) from continuing operations before income taxes	1,597	-574		832
Income tax benefit (provision)	-556	213		-288
Income (loss) from continuing operations	1,041	-361		544
Loss from discontinued operations, net of tax	-111	-438		-301
Net income (loss)	930	-799		243
Net income attributable to noncontrolling interests	0	-39		-51
Net income (loss) attributable to common stockholders	930	-838		192
Basic earnings per share:
Income (loss) from continuing operations attributable to common stockholders	$7.17	($2.94)		$3.99
Loss from discontinued operations attributable to common stockholders	($0.77)	($3.22)		($2.45)
Net income (loss) attributable to common stockholders	$6.40	($6.16)		$1.54
Diluted earnings per share:
Income (loss) from continuing operations attributable to common stockholders	$7.15	($2.94)		$3.88
Loss from discontinued operations attributable to common stockholders	($0.77)	($3.22)		($2.38)
Net income (loss) attributable to common stockholders	$6.38	($6.16)		$1.50
Weighted average shares outstanding:
Basic	144	136	[1]	123
Diluted	144	136	[1]	126
Amounts attributable to common stockholders:
Income (loss) from continuing operations, net of tax	1,041	-400		493
Income (loss) from discontinued operations, net of tax	-111	-438		-301
Net income (loss)	$930	($838)		$192

[1]	(a)The following common share equivalents were excluded from the weighted average diluted shares for the year ended December 31, 2013 because they would have been anti-dilutive to the loss recorded for the period: (i) 135,190 outstanding options to purchase the Company's common stock, (ii) 200,360 common shares attributable to unvested performance awards and (iii) 1,087,401 common shares related to the 2013 redemption of the Convertible Senior Notes, representing the weighted average portion of the year that is not included in the basic weighted average common shares outstanding.

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income (loss)	$930	($799)	$243
Other comprehensive activity:
Net hedge (gains) losses included in continuing operations	0	0	5
Income tax (benefit) provision	0	0	-2
Other comprehensive activity	0	0	3
Comprehensive income (loss)	930	-799	246
Comprehensive income attributable to the noncontrolling interests	0	-39	-51
Comprehensive income (loss) attributable to common stockholders	$930	($838)	$195

Consolidated_Statements_Of_Sto

Consolidated Statements Of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Pioneer Southwest [Member]
In Millions, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Additional Paid-In Capital [Member]
Beginning Balance at Dec. 31, 2011	$5,651	$1	$3,614	($458)	$2,335	($3)	$162
Beginning Balance, shares at Dec. 31, 2011	122,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared ($0.08 per share)	-10				-10
Exercise of long-term incentive plan stock options and employee stock purchases, shares	0
Exercise of long-term incentive plan stock options and employee stock purchases	7		-1	11	-3
Purchase of treasury stock, shares	-1,000,000
Purchase of treasury stock	-63			-63			0
Tax benefits related to stock-based compensation	58		58
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	-49		-49					-49
Pioneer Southwest merger transaction costs								0
Pioneer Southwest noncontrolling interest transferred to APIC								0
Deferred tax benefit associated with the Pioneer Southwest merger	0							0
Compensation costs:
Vested compensation awards, net, shares	2,000,000
Vested compensation awards, net	0	0	0
Compensation costs included in net income	63		62				1
Cash distributions to noncontrolling interests	-36						-36
Net income (loss)	243				192		51
Deferred hedging activity, net of tax:
Net hedge (gains) losses included in continuing operations	3					3	0
Ending Balance at Dec. 31, 2012	5,867	1	3,684	-510	2,514	0	178
Ending Balance, shares at Dec. 31, 2012	123,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues	10,350,000
Issuance of Common Stock	1,281	0	1,281
Dividends declared ($0.08 per share)	-11				-11
Exercise of long-term incentive plan stock options and employee stock purchases, shares	0
Exercise of long-term incentive plan stock options and employee stock purchases	10		0	10	0
Purchase of treasury stock, shares	0
Purchase of treasury stock	-20			-20			0
Conversion of 2.875% senior convertible notes, shares	5,000,000
Stock Issued During Period, Value, Conversion of Convertible Securities	0		-197	197
Deferred tax benefit related to conversion of 2.875% senior convertible notes	38		38
Tax benefits related to stock-based compensation	18		18
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	0							0
Issuance of treasury stock to acquire outstanding PSE units, shares	3,960,000
Issuance of treasury stock to acquire outstanding PSE units	0		-179	179
Pioneer Southwest merger transaction costs	-4		-4					-4
Pioneer Southwest noncontrolling interest transferred to APIC	0		169				-169	169
Deferred tax benefit associated with the Pioneer Southwest merger	200		200					200
Compensation costs:
Vested compensation awards, net, shares	1,000,000
Vested compensation awards, net	0	0	0
Compensation costs included in net income	71		70				1
Cash distributions to noncontrolling interests	-36						-36
Net income (loss)	-799				-838		39
Ending Balance at Dec. 31, 2013	6,615	1	5,080	-144	1,665	0	13
Ending Balance, shares at Dec. 31, 2013	143,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues	5,750,000
Issuance of Common Stock	980	1	979
Dividends declared ($0.08 per share)	-12				-12
Exercise of long-term incentive plan stock options and employee stock purchases, shares	0
Exercise of long-term incentive plan stock options and employee stock purchases	13		6	7	0
Purchase of treasury stock, shares	0
Purchase of treasury stock	-34			-34
Noncontrolling Interest, Decrease from Deconsolidation	-4						-4
Tax benefits related to stock-based compensation	19		19
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	0							0
Pioneer Southwest merger transaction costs	-1		-1					-1
Pioneer Southwest noncontrolling interest transferred to APIC								0
Deferred tax benefit associated with the Pioneer Southwest merger	0							0
Compensation costs:
Vested compensation awards, net, shares	0
Vested compensation awards, net	0	0	0
Compensation costs included in net income	84		84				0
Cash distributions to noncontrolling interests	-1						-1
Net income (loss)	930				930		0
Ending Balance at Dec. 31, 2014	$8,589	$2	$6,167	($171)	$2,583		$8
Ending Balance, shares at Dec. 31, 2014	149,000,000

Consolidated_Statements_Of_Sto1

Consolidated Statements Of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Dividends declared, per share	$0.08	$0.08	$0.08

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income (loss)	$930	($799)	$243
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depletion, depreciation and amortization	1,047	889	689
Impairment of oil and gas properties	0	1,495	0
Impairment of inventory and other property and equipment	8	62	6
Exploration expenses, including dry holes	90	21	31
Deferred income taxes	552	-224	284
Gain on disposition of assets, net	-9	-209	-46
Accretion of discount on asset retirement obligations	12	12	8
Discontinued operations	251	633	520
Interest expense	17	17	36
Derivative related activity	-609	164	69
Amortization of stock-based compensation	84	71	63
Amortization of deferred revenue	0	0	-42
Other	34	-6	-47
Change in operating assets and liabilities
Accounts receivable, net	-29	-123	-28
Income taxes receivable	-18	3	-6
Inventories	-37	-39	33
Prepaid expenses	-3	-1	1
Other current assets	1	4	14
Accounts payable	104	209	46
Interest payable	-22	-6	11
Income taxes payable	1	0	-10
Other current liabilities	-38	-27	-38
Net cash provided by operating activities	2,366	2,146	1,837
Cash flows from investing activities:
Proceeds from disposition of assets, net of cash sold	877	711	96
Payments for acquisitions, net of cash acquired	0	0	-297
Distribution from (investment in) unconsolidated subsidiary	0	25	0
Additions to oil and gas properties	-3,243	-2,639	-2,758
Additions to other assets and other property and equipment, net	-333	-237	-297
Net cash used in investing activities	-2,699	-2,140	-3,256
Cash flows from financing activities:
Borrowings under long-term debt	523	467	1,777
Principal payments on long-term debt	-523	-1,547	-612
Proceeds from issuance of common stock, net of issuance	980	1,281	0
Distributions to noncontrolling interests	-1	-36	-36
Payments of other liabilities	0	-4	-1
Exercise of long-term incentive plan stock options and employee stock purchases	13	10	7
Purchase of treasury stock	-34	-20	-63
Excess tax benefits from share-based payment arrangements	19	18	58
Payment of financing fees	0	0	-9
Dividends paid	-12	-11	-10
Net cash provided by financing activities	965	158	1,111
Net increase (decrease) in cash and cash equivalents	632	164	-308
Cash and cash equivalents, beginning of period	393	229	537
Cash and cash equivalents, end of period	$1,025	$393	$229

Organization_And_Nature_Of_Ope

Organization And Nature Of Operations	12 Months Ended
Organization And Nature Of Operations	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization And Nature Of Operations	NOTE A. 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 in the United States, with operations primarily in the Permian Basin in West Texas, the Eagle Ford Shale play in South Texas, the Raton field in southeastern Colorado and the West Panhandle field in the Texas Panhandle. The Company's objective is to maximize shareholder investment returns by maintaining financial flexibility, capital allocation discipline and enhancing net asset value through accretive drilling programs, joint ventures and acquisitions.

Summary_Of_Significant_Account

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	NOTE B. Summary of Significant Accounting Policies
	Principles of consolidation. The consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries since their acquisition or formation. All material intercompany balances and transactions have been eliminated.
	Certain reclassifications have been made to the 2013 and 2012 financial statement and footnote amounts in order to conform them to the 2014 presentations.
	Use of estimates in the preparation of financial statements. Preparation of the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Depletion of oil and gas properties and impairment of goodwill and proved and unproved oil and gas properties, in part, is determined using estimates of proved, probable and possible oil and gas reserves. There are numerous uncertainties inherent in the estimation of quantities of proved, probable and possible reserves and in the projection of future rates of production and the timing of development expenditures. Similarly, evaluations for impairment of proved and unproved oil and gas properties are subject to numerous uncertainties including, among others, estimates of future recoverable reserves and commodity price outlooks. Actual results could differ from the estimates and assumptions utilized.
	Cash and cash equivalents. The Company's cash and cash equivalents include depository accounts held by banks and marketable securities with original issuance maturities of 90 days or less.
	Accounts receivable. As of December 31, 2014 and 2013, the Company had accounts receivable – trade, net of allowances for bad debts, of $436 million and $431 million, respectively. The Company's accounts receivable – trade are primarily comprised of oil and gas sales receivables, joint interest receivables and other receivables for which the Company does not require collateral security.
	As of both December 31, 2014 and 2013, the Company's allowances for doubtful accounts totaled $1 million. The Company establishes allowances for bad debts equal to the estimable portions of accounts receivable for which failure to collect is considered probable. The Company estimates the portions of joint interest receivables for which failure to collect is probable based on percentages of joint interest receivables that are past due. The Company estimates the portions of other receivables for which failure to collect is probable based on the relevant facts and circumstances surrounding the receivable. Allowances for doubtful accounts are recorded as reductions to the carrying values of the receivables included in the Company's consolidated balance sheets and as charges to other expense in the consolidated statements of operations in the accounting periods during which failure to collect an estimable portion is determined to be probable.
	Inventories. The Company's inventories consist of materials, supplies and commodities. The Company's materials and supplies inventory is primarily comprised of oil and gas drilling or repair items such as tubing, casing, proppant used to fracture-stimulate oil and gas wells, chemicals, operating supplies and ordinary maintenance materials and parts. The materials and supplies inventory is primarily acquired for use in future drilling operations or repair operations and is carried at the lower of cost or market, on a first-in, first-out cost basis. Valuation allowances for materials and supplies inventories are recorded as reductions to the carrying values of the materials and supplies inventories in the Company's consolidated balance sheets and as charges to other expense in the accompanying consolidated statements of operations.
	Commodity inventories are carried at the lower of cost or market, on a first-in, first-out basis. The Company's commodity inventories consist of oil, natural gas liquids ("NGLs") and gas volumes held in storage or as linefill in pipelines. Any valuation allowances of commodity inventories are recorded as reductions to the carrying values of the commodity inventories included in the Company's consolidated balance sheets and as charges to other expense in the consolidated statements of operations.
	The following table presents the Company's materials and supplies and commodity inventories as of December 31, 2014 and 2013:


			As of December 31,
			2014				2013
			(in millions)
	Materials and supplies (a)		$	223			$	211

	Commodities		18				13

	Less: Noncurrent materials and supplies (b)		—				(4		)

			$	241			$	220

	____________________

	(a)	As of December 31, 2014 and 2013, the Company's materials and supplies inventories were net of valuation allowances of $22 million and $32 million, respectively. See Note D for additional information regarding inventory impairments.

	(b)	Included in other noncurrent assets in the Company's accompanying consolidated balance sheet.
	Oil and gas properties. The Company utilizes the successful efforts method of accounting for its oil and gas properties. Under this method, all costs associated with productive wells and nonproductive development wells are capitalized while nonproductive exploration costs and geological and geophysical expenditures are expensed. The Company capitalizes interest on expenditures for significant development projects, generally when the underlying project is sanctioned, until such projects are ready for their intended use.
	The Company does not carry the costs of drilling an exploratory well as an asset in its consolidated balance sheets following the completion of drilling unless both of the following conditions are met:

	(i)	The well has found a sufficient quantity of reserves to justify its completion as a producing well.

	(ii)	The Company is making sufficient progress assessing the reserves and the economic and operating viability of the project.
	Due to the capital intensive nature and the geographical location of certain projects, it may take an extended period of time to evaluate the future potential of an exploration project and the economics associated with making a determination on its commercial viability. In these instances, the project's feasibility is not contingent upon price improvements or advances in technology, but rather the Company's ongoing efforts and expenditures related to accurately predicting the hydrocarbon recoverability based on well information, gaining access to other companies' production data in the area, transportation or processing facilities and/or getting partner approval to drill additional appraisal wells. These activities are ongoing and are being pursued constantly. Consequently, the Company's assessment of suspended exploratory well costs is continuous until a decision can be made that the project has found sufficient proved reserves to sanction the project or is noncommercial and is charged to exploration and abandonments expense. See Note F for additional information regarding the Company's suspended exploratory well costs.
	The Company owns interests in six gas processing plants and eight treating facilities. The Company is the operator of one of the gas processing plants and all eight of the treating facilities. The Company's ownership interests in the gas processing plants and treating facilities are primarily to accommodate handling the Company's gas production and thus are considered a component of the capital and operating costs of the respective fields that they service. To the extent that there is excess capacity at a plant or treating facility, the Company attempts to process third party gas volumes for a fee to keep the plant or treating facility at capacity. All revenues and expenses derived from third party gas volumes processed through the plants and treating facilities are reported as components of oil and gas production costs. Third party revenues generated from the processing plants and treating facilities in continuing operations for the years ended December 31, 2014, 2013 and 2012 were $56 million, $53 million and $31 million, respectively. Third party expenses attributable to the processing plants and treating facilities in continuing operations for the same respective periods were $24 million, $21 million and $19 million. The capitalized costs of the plants and treating facilities are included in proved oil and gas properties and are depleted using the unit-of-production method along with the other capitalized costs of the field that they service.
	The capitalized costs of proved properties are depleted using the unit-of-production method based on proved reserves. Costs of significant nonproducing properties, wells in the process of being drilled and development projects are excluded from depletion until the related project is completed and proved reserves are established or, if unsuccessful, impairment is determined.
	Proceeds from the sales of individual properties and the capitalized costs of individual properties sold or abandoned are credited and charged, respectively, to accumulated depletion, depreciation and amortization, if doing so does not materially impact the depletion rate of an amortization base. Generally, no gain or loss is recognized until an entire amortization base is sold. However, gain or loss is recognized from the sale of less than an entire amortization base if the disposition is significant enough to materially impact the depletion rate of the remaining properties in the amortization base.
	The Company performs assessments of its long-lived assets to be held and used, including proved oil and gas properties accounted for under the successful efforts method of accounting, whenever events or circumstances indicate that the carrying value of those assets may not be recoverable. An impairment loss is indicated if the sum of the expected future cash flows is less than the carrying amount of the assets. In these circumstances, the Company recognizes an impairment loss for the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets. See Note D for additional information regarding the Company's impairment of proved oil and gas properties.
	Unproved oil and gas properties are periodically assessed for impairment on a project-by-project basis. These impairment assessments are affected by the results of exploration activities, commodity price outlooks, planned future sales or expirations of all or a portion of such projects. If the estimated future net cash flows attributable to such projects are not expected to be sufficient to fully recover the costs invested in each project, the Company will recognize an impairment loss at that time.
	Goodwill. During 2004, the Company recorded goodwill associated with a business combination, which represents the cost of an acquired entity over the net amounts assigned to assets acquired and liabilities assumed. In accordance with GAAP, goodwill is not amortized to earnings, but is assessed for impairment whenever events or circumstances indicate that impairment of the carrying value of goodwill is likely, but no less often than annually. If the carrying value of goodwill is determined to be impaired, it is reduced for the impaired value with a corresponding charge to earnings in the period in which it is determined to be impaired. During the third quarter of 2014, the Company performed its annual qualitative assessment of goodwill to determine whether it was more likely than not that the fair value of the Company's reporting unit was less than its carrying amount as a basis for determining whether it was necessary to perform the two-step goodwill impairment test. The Company reevaluated this assessment during the fourth quarter of 2014 due to reductions in (i) management's longer-term commodity price outlooks ("Management's Price Outlooks") and (ii) the Company's common stock price. Based upon the results of the assessments, the Company determined that it was not likely that the Company's goodwill was impaired.
	The Company reduced the carrying value of goodwill by $2 million and $24 million during the years ended December 31, 2014 and 2013, respectively, reflecting the portion of the Company's goodwill related to assets sold or included in assets held for sale. During 2014, the reduction of goodwill primarily reflected the Company's goodwill related to the Hugoton field assets sold in September 2014, while the 2013 reduction was primarily associated with the sale of 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, and the planned sales of the Company's Alaska subsidiary and Barnett Shale net assets that were subsequently completed during 2014. See Note C for additional information regarding the Company's divestitures.
	Other property and equipment, net. Other property and equipment is recorded at cost. At December 31, 2014 and 2013, respectively, the net carrying value of other property and equipment consisted of the following:


			As of December 31,
			2014 (a)				2013 (a)
			(in millions)
	Proved and unproved sand properties (b)		$	469			$	451

	Land and buildings		440				345

	Equipment and rigs (c)		348				313

	Transportation equipment		35				41

	Furniture and fixtures		70				48

	Leasehold improvements		29				26

			$	1,391			$	1,224

	____________________

(a)	At December 31, 2014 and 2013, other property and equipment was net of accumulated depreciation of $563 million and $458 million, respectively.

(b)	Includes sand mines, facilities and unproved leaseholds that primarily provide the Company and other unrelated customers with proppant used in the fracture stimulation of oil and gas wells.

(c)	Includes well servicing rigs and equipment and fracture stimulation equipment including assets owned by subsidiaries that provide pumping and well services on Company-operated properties. As of December 31, 2014, the Company owned eight fracture stimulation fleets and other oilfield services equipment, including pulling units, fracture stimulation tanks, water transport trucks, hot oilers, blowout preventers, construction equipment and fishing tools.
The primary purposes of the Company's sand mines and pumping and well services operations are to accommodate the Company's drilling and producing operations by increasing the availability of supplies, equipment and services, rather than being dependent on third-party availability, and to contain associated costs. All intercompany gains or losses of the Company's sand mines and pumping and well services operations are eliminated.
Earnings from sales of proppant to third-party customers and from providing pumping and well services to working interest owners in Company-operated properties are included in interest and other income in the accompanying consolidated statements of operations.
The capitalized costs of proved sand properties are depleted using the unit-of-production method based on proved sand reserves. Equipment items are generally depreciated by individual component on a straight line basis over their economic useful lives, which are generally from two to 12 years. Leasehold improvements are amortized over the lesser of their economic useful lives or the underlying terms of the associated leases.
The Company evaluates other property and equipment for potential impairment whenever indicators of impairment are present. Circumstances that could indicate potential impairment include: significant adverse changes in industry trends and the economic outlook; legal actions; regulatory changes; and significant declines in utilization rates or oil and gas prices. If it is determined that other property and equipment is potentially impaired, the Company performs an impairment evaluation by estimating the future undiscounted net cash flow from the use and eventual disposition of other property and equipment grouped at the lowest level that cash flows can be identified. If the sum of the future undiscounted net cash flows is less than the net book value of the property, an impairment loss is recognized for the excess, if any, of the assets' net book value over its estimated fair value.
Investment in unconsolidated affiliate. During 2010, the Company formed EFS Midstream LLC ("EFS Midstream") to own and operate gas and liquids gathering, treating and transportation assets in the Eagle Ford Shale play in South Texas. During June 2010, the Company sold a 49.9 percent member interest in EFS Midstream to an unaffiliated third party for $46 million of cash proceeds. Associated therewith, the Company recorded a deferred gain that is being amortized as a reduction in production costs over a 20 year period, representing the term of a continuing commitment of Pioneer to deliver production volumes through EFS Midstream handling and gathering facilities. As of December 31, 2014, the deferred gain totaled $39 million and is included in other current and noncurrent liabilities in the Company's accompanying consolidated balance sheet.
The Company does not have control of EFS Midstream. Consequently, the Company accounts for this investment under the equity method of accounting for investments in unconsolidated affiliates. Under the equity method, the Company's investment in unconsolidated affiliates is increased for investments made and the investor's share of the investee's net income, and decreased for distributions received, the carrying value of member interests sold and the investor's share of the investee's net losses.
The Company's equity interest in the net income or loss of EFS Midstream is recorded in interest and other income, net of eliminations of the profit associated with gathering, treating and transportation fees charged to the Company by EFS Midstream, in the accompanying consolidated statements of operations. See Note M for the Company's equity interest in the net income of EFS Midstream for the years ended December 31, 2014, 2013 and 2012.
During November 2014, the Company announced that it is pursuing the divestment of its 50.1 percent share of EFS Midstream. The Company is marketing its equity investment in EFS Midstream and no assurance can be given that a sale will be completed in accordance with the Company's plans or on terms and at a price acceptable to the Company.
Asset retirement obligations. The Company records a liability for the fair value of an asset retirement obligation in the period in which it is incurred if a reasonable estimate of fair value can be made. Asset retirement obligations are generally capitalized as part of the carrying value of the long-lived asset to which it relates. Conditional asset retirement obligations meet the definition of liabilities and are recognized when incurred if their fair values can be reasonably estimated.
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 and expenditures are classified as cash used in operating activities in the accompanying consolidated statements of cash flows. See Note I for additional information about the Company's asset retirement obligations.
Treasury stock. Treasury stock purchases are recorded at cost. Upon reissuance, the cost of treasury shares held is reduced by the average purchase price per share of the aggregate treasury shares held.
Issuance of common stock. In November 2014 and February 2013, the Company issued 5.75 million shares and 10.35 million shares of its common stock, respectively, and realized cash proceeds of $980 million and $1.3 billion, respectively, net of associated underwriting and offering expenses.
Noncontrolling interest in consolidated subsidiaries. The Company owns the majority interests in certain subsidiaries with operations in the United States. Prior to December 17, 2013, the Company owned a 0.1 percent general partner interest and a 52.4 percent limited partner interest in Pioneer Southwest Energy Partners L.P. ("Pioneer Southwest") and consolidated the financial position, results of operations and cash flows of Pioneer Southwest with those of Pioneer. Pioneer Southwest owned proved and unproved oil and gas properties in the Spraberry field in the Permian Basin of West Texas. On December 17, 2013, the holders of a majority of the outstanding common units of Pioneer Southwest approved an amended agreement and plan of merger, pursuant to which (i) all of the then outstanding common units of Pioneer Southwest were canceled and converted into the right to receive 0.2325 of a share of common stock of the Company and (ii) Pioneer Southwest became a wholly-owned subsidiary of the Company. The changes in the Company's ownership of Pioneer Southwest were accounted for by eliminating the noncontrolling interest attributable to Pioneer Southwest. See Note C for additional information about Pioneer Southwest and the amended agreement and plan of merger.
Noncontrolling interests in the net assets of consolidated subsidiaries totaled $8 million and $13 million as of December 31, 2014 and 2013, respectively. For the year ended December 31, 2014, the Company recorded a nominal net loss attributable to the noncontrolling interests, as compared to $39 million and $51 million of net income attributable to the noncontrolling interests for the years ended December 31, 2013 and 2012, respectively. The decrease in income attributable to noncontrolling interests for the year ended December 31, 2014, as compared to 2013 and 2012, is due to the Company's acquisition of all of the outstanding common units of Pioneer Southwest not owned by the Company in December 2013.
In accordance with GAAP, the Company records transfers of any gains or losses, net of taxes, from noncontrolling interests in consolidated subsidiaries to additional paid in capital proportionate to the ownership after giving effect to the purchase or sale of common units. The following table presents the Company's net income or loss attributable to common stockholders adjusted for changes in equity as a result of transactions that changed the Company's ownership interest in Pioneer Southwest:



	Year Ended December 31,
	2014				2013				2012
	(in millions)
Net income (loss) attributable to common stockholders	$	930			$	(838	)		$	192

Transfers from the noncontrolling interest in consolidated subsidiaries:
Decrease in additional paid-in capital for deferred taxes recognized attributable to Pioneer Southwest's 2008 initial public offering of 9.5 million common units	—				—				(49		)

Increase in additional paid-in capital from Pioneer Southwest merger	—				169				—

Increase in additional paid-in capital from deferred taxes recognized attributable to Pioneer Southwest merger	—				200				—

Decrease in additional paid-in capital from Pioneer Southwest merger transaction costs	(1		)		(4		)		—

Net increase (decrease) in equity from transactions with noncontrolling interests	(1		)		365				(49		)

Net income (loss) attributable to common stockholders and changes in equity from transactions with noncontrolling interests	$	929			$	(473	)		$	143

Revenue recognition. The Company recognizes revenue when it is realized or realizable and earned. Revenues are considered realized or realizable and earned when: (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the seller's price to the buyer is fixed or determinable and (iv) collectability is reasonably assured.
The Company uses the entitlements method of accounting for oil, NGLs and gas revenues. Sales proceeds in excess of the Company's entitlement are included in other liabilities and the Company's share of sales taken by others is included in other assets in the accompanying consolidated balance sheets. The Company had no material oil, NGL or gas entitlement assets or liabilities as of December 31, 2014 or 2013.

The Company enters into purchase transactions with third parties and separate sale transactions with third parties to satisfy unused pipeline capacity commitments and to diversify a portion of the Company's WTI oil sales to a Gulf Coast market price. Revenues and expenses from these transactions are presented on a gross basis as the Company acts as a principal in the transaction by assuming the risk and rewards of ownership, including credit risk, of the commodities purchased and assuming responsibility to deliver the commodities sold. Deficiency payments on excess pipeline capacity are included in other expense in the accompanying consolidated statements of operations. See Note N for further information on transportation commitment charges.
Derivatives. All derivatives are recorded in the accompanying consolidated balance sheets at estimated fair value. Effective February 1, 2009, the Company discontinued hedge accounting on all of its then-existing hedge contracts. The effective portions of the discontinued deferred hedges as of February 1, 2009 were included in accumulated other comprehensive income (loss) ("AOCI - Hedging") and were transferred to earnings during the same periods in which the forecasted hedged transactions were recognized in the Company's earnings. During 2012, the remaining AOCI - Hedging losses were transferred to earnings. Since discontinuing hedge accounting, the Company has recognized all changes in the fair values of its derivative contracts 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 executed under master netting arrangements as net current or noncurrent derivative assets or net current or noncurrent derivative liabilities, whichever the case may be, by commodity and counterparty. Net derivative asset values are determined, in part, by utilization of the derivative counterparties' credit-adjusted risk-free rate curves and net derivative liabilities are determined, in part, by utilization of the Company's credit-adjusted risk-free rate curve. The credit-adjusted risk-free rate curves for the Company and the counterparties are based on their independent market-quoted credit default swap rate curves plus the United States Treasury Bill yield curve as of the valuation date. See Note E for additional information about the Company's derivative instruments.
Environmental. The Company's environmental expenditures are expensed or capitalized depending on their future economic benefit. Expenditures that relate to an existing condition caused by past operations and that have no future economic benefits are expensed. Expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities for expenditures that will not qualify for capitalization are recorded when environmental assessment and/or remediation is probable and the costs can be reasonably estimated. Such liabilities are undiscounted unless the timing of cash payments for the liability is fixed or reliably determinable. Environmental liabilities normally involve estimates that are subject to revision until settlement occurs.
Stock-based compensation. Stock-based compensation expense is being recognized on restricted stock, restricted stock units, performance units and stock option awards that are expected to be settled in the Company's common stock ("Equity Awards") in the Company's financial statements on a straight line basis over the awards' vesting periods based on their fair values on the dates of grant or modification, as applicable. Stock-based compensation awards generally vest over a period of three years. The amount of stock-based compensation expense recognized at any date is approximately equal to the ratable portion of the grant date value of the award that is vested at that date.
Stock-based compensation liability awards ("Liability Awards") are restricted stock awards that are expected to be settled in cash on their vesting dates, rather than in common stock. Liability Awards are recorded as accounts payable—affiliates based on the vested portion of the fair value of the awards on the balance sheet date. The fair values of Liability Awards are updated at each balance sheet date and changes in the fair values of the vested portions of the awards are recorded as increases or decreases to stock-based compensation expense.
The Company utilizes (i) the Black-Scholes option pricing model to measure the fair value of stock options, (ii) the prior day's closing stock price on the date of grant for the fair value of Equity Awards and Liability Awards and (iii) the Monte Carlo simulation method for the fair value of performance unit awards.
Segments. Operating segments are defined as components of an enterprise that (i) engage in activities from which it may earn revenues and incur expenses (ii) for which separate operational financial information is available and is regularly evaluated by the chief operating decision maker for the purpose of allocating resources and assessing performance.
Based upon how the Company is organized and managed, the Company has only one reportable operating segment, which is oil and gas exploration and production. The Company considers its vertical integration services as ancillary to its oil and gas exploration and producing activities and manages these services to support such activities. In addition, the Company has a single, company-wide management team that allocates capital resources to maximize profitability and measures financial performance as a single enterprise.
Assets held for sale and discontinued operations. On the date at which the Company meets all the held for sale criteria, the Company discontinues the recording of depletion and depreciation of the assets or asset group to be sold and reclassifies the assets and related liabilities to be sold as held for sale on the accompanying consolidated balance sheets. The assets and liabilities are measured at the lower of their carrying amount or estimated fair value less cost to sell.
In addition, after determining that held for sale criteria has been met, the Company considers whether the assets held for sale meet the criteria to be considered discontinued operations. If the assets held for sale are considered discontinued operations, the Company classifies the results of operations from the assets held for sale as income or loss from discontinued operations, net of tax in the accompanying consolidated statements of operations for the current period and all prior periods. See Note C for additional information about the Company's divestitures.
New accounting pronouncements. In February 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements.
In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)," which supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") Topic 605, "Revenue Recognition," and most industry-specific guidance. ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB ASC. The new guidance is effective for annual reporting periods beginning after December 15, 2016 for public companies. Early adoption is not permitted. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements or decided upon the method of adoption.
In April 2014, the FASB issued ASU 2014-08, "Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity." ASU 2014-08 prospectively changes the criteria for reporting discontinued operations while enhancing disclosures around disposals of assets whether or not the disposal meets the definition of a discontinued operation. ASU 2014-08 is effective for annual and interim periods beginning after December 31, 2014 with early adoption permitted but only for disposals that have not been reported in financial statements previously issued. The impact of this guidance on the Company's consolidated financial statements will depend on the size and nature of the Company's disposal transactions in the future, which the Company cannot accurately predict. Several of the Company's past dispositions that were treated as discontinued operations may not have been classified as such had the new guidance been in effect.

Acquisitions_and_Divestitures

Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisition and Divestitures [Text Block]	NOTE C. Acquisitions and Divestitures
	Divestitures Recorded in Continuing Operations
	The Company recorded net gains on the disposition of assets in continuing operations of $9 million, $209 million and $46 million during the years ended December 31, 2014, 2013 and 2012, respectively. The following describes the significant divestitures included in continuing operations:

	•	Vertical drilling rigs. During December 2013, the Company committed to a plan to sell the Company's majority interest in Sendero Drilling Company, LLC ("Sendero") to Sendero's minority interest owner. At December 31, 2013, the assets and liabilities of Sendero were classified as held for sale at their estimated fair value. In March 2014, the Company completed the sale of Sendero for cash proceeds of $31 million . As part of the sales agreement, the Company committed to lease from Sendero 12 vertical rigs through December 31, 2015 and eight vertical rigs in 2016. See Note D for information about impairment charges related to Sendero.

	•	Permian Basin. During February 2014, the Company completed the sale of proved and unproved properties in Gaines and Dawson counties in the Spraberry field in West Texas for cash proceeds of $72 million, which resulted in a gain of $2 million on the unproved property sold.

	•	Southern Wolfcamp. In January 2013, the Company signed an agreement with Sinochem Petroleum USA LLC ("Sinochem") 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. In May 2013, the Company completed the sale for cash proceeds of $624 million, which resulted in a gain of $181 million related to the unproved property interests conveyed to Sinochem. 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 southern portion of the horizontal Wolfcamp Shale play. At December 31, 2014, the unused carry balance totaled $575 million.

	•	West Panhandle. During the first quarter of 2013, the Company completed a sale of its interest in unproved oil and gas properties adjacent to the Company's West Panhandle field operations for net cash proceeds of $38 million, which resulted in a gain of $22 million.

	•	Eagle Ford Shale. In January 2012, the Company sold a portion of its interest in an unproved oil and gas property in the Eagle Ford Shale play to unaffiliated third parties for cash proceeds of $55 million, which resulted in a gain of $43 million.

	•	Other. During 2014, 2013 and 2012, the Company sold other proved and unproved properties, inventory and other property and equipment and recorded net gains of $4 million, $5 million and $3 million, respectively.
	Divestitures Recorded in Discontinued Operations
	The Company has reflected its Hugoton, Barnett Shale, Pioneer Alaska and Pioneer South Africa results of operations as discontinued operations in the accompanying consolidated statements of operations.
	Hugoton. In September 2014, the Company completed the sale of its net assets in the Hugoton field in southwest Kansas for cash proceeds of $328 million, including normal closing adjustments. See Note D for information about impairment charges on the Hugoton assets.
	Barnett Shale. During the fourth quarter of 2013, the Company committed to a plan to divest of its net assets in the Barnett Shale field in North Texas. In September 2014, the Company completed the sale of its Barnett Shale net assets for cash proceeds of $150 million, including normal closing adjustments. See Note D for information about impairment charges on the Barnett Shale assets. Also included in discontinued operations in 2013 is the sale of the Company's interest in certain proved and unproved oil and gas properties in the Barnett Shale field for net cash proceeds of $34 million, which resulted in a gain of $9 million on the unproved properties sold.
	Alaska. During the fourth quarter of 2013, the Company committed to a plan to sell 100 percent of the capital stock in Pioneer's Alaska subsidiary ("Pioneer Alaska"). In April 2014, the Company completed the sale of Pioneer Alaska for cash proceeds of $267 million, including normal closing and other adjustments. See Note D for information about impairment charges on Pioneer Alaska. The recasting of Pioneer Alaska results to income (loss) from discontinued operations includes the sale of the Company's interest in the Cosmopolitan Unit in the Cook Inlet of Alaska in August 2012 for cash proceeds of $10 million, which, together with certain Company obligations assumed by the purchasers, resulted in a gain of $13 million.
	South Africa. During the first quarter of 2012, the Company agreed to sell its net assets in South Africa ("Pioneer South Africa"), effective January 1, 2012, for $60 million of cash proceeds before normal closing and other adjustments, and the buyer's assumption of certain liabilities of the Company's South Africa subsidiaries. In August 2012, the Company completed the sale of Pioneer South Africa for cash proceeds of $16 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 gain of $29 million.

	The following table represents the components of the Company's discontinued operations for the years ended December 31, 2014, 2013 and 2012:


			Year Ended December 31,
			2014			2013			2012
			(in millions)
	Revenues and other income:
	Oil and gas		$	198		$	329		$	349

	Interest and other (a)		31			38			29

	Gain on disposition of assets, net		9			9			41

			238			376			419

	Costs and expenses:
	Oil and gas production		60			117			107

	Production and ad valorem taxes		12			19			19

	Depletion, depreciation and amortization		11			122			121

	Impairment of oil and gas properties (b)		305			729			533

	Exploration and abandonments		4			54			109

	General and administrative		3			12			6

	Accretion of discount on asset retirement obligations		1			1			3

	Other		13			9			3

			409			1,063			901

	Loss from discontinued operations before income taxes		(171		)	(687		)	(482		)
	Current tax provision		—			(6		)	(10		)

	Deferred tax benefit		60			255			191

	Loss from discontinued operations		$	(111	)	$	(438	)	$	(301	)
	____________________

(a)	Primarily comprised of Alaskan Petroleum Production Tax credits on qualifying capital expenditures.

(b)	Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.

As of December 31, 2013, the carrying values of the Company's ownership in Pioneer Alaska, the Barnett Shale field and Sendero were included in assets and liabilities held for sale in the accompanying consolidated balance sheet and were comprised of the following (the Company had no assets held for sale as of December 31, 2014):


		31-Dec-13
		(in millions)
Composition of assets included in assets held for sale:
Current assets (excluding cash and cash equivalents)		$	58

Property, plant and equipment		526

Total assets		$	584


Composition of liabilities included in liabilities held for sale:
Current liabilities		$	29

Other liabilities		10

Total liabilities		$	39

Acquisitions
Affiliated Partnerships. In December 2014, the Company acquired the remaining limited partner interests in five affiliated partnerships for $54 million and caused the partnerships to be merged with and into a wholly-owned subsidiary of the Company.
Pioneer Southwest Merger Transaction. In December 2013, the Company completed the acquisition of all of the outstanding common units of Pioneer Southwest not already owned by the Company, through a merger of a wholly-owned subsidiary of the Company into Pioneer Southwest, the result of which was that Pioneer Southwest became a wholly-owned subsidiary of the Company. All of the common units outstanding as of the closing of the merger, except for the common units owned by the Company, were canceled and converted into the right to receive 0.2325 of a share of common stock of the Company per common unit (the "Conversion Ratio"). Consequently, in December 2013, the Company issued an aggregate of 3.96 million shares of its common stock to Pioneer Southwest unitholders.
The Company subsequently caused Pioneer Southwest, its general partner and all of Pioneer Southwest's subsidiaries to be merged with and into a wholly-owned subsidiary of the Company, the result of which was that all common units of Pioneer Southwest were canceled and the Company no longer holds any common units.
Premier Silica Business Combination. In April 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 million, including closing adjustments.

Disclosures_About_Fair_Value_M

Disclosures About Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Disclosures About Fair Value Measurements	NOTE D. 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 tables present the Company's assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2014 and 2013 for each of the fair value hierarchy levels:



		Fair Value Measurements at December 31, 2014 Using
		Quoted Prices in				Significant Other				Significant				Fair Value at December 31, 2014
		Active Markets for				Observable				Unobservable
		Identical Assets				Inputs				Inputs
		(Level 1)				(Level 2)				(Level 3)
		(in millions)
	Assets:
	Commodity derivatives	$	—			$	759			$	—			$	759

	Deferred compensation plan assets	70				—				—				70

	Total assets	70				759				—				829

	Liabilities:
	Commodity derivatives	—				2				—				2

	Interest rate derivatives	—				3				—				3

	Total liabilities	—				5				—				5

	Total recurring fair value measurements	$	70			$	754			$	—			$	824




		Fair Value Measurements at December 31, 2013 Using
		Quoted Prices in				Significant Other				Significant				Fair Value at December 31, 2013
		Active Markets for				Observable				Unobservable
		Identical Assets				Inputs				Inputs
		(Level 1)				(Level 2)				(Level 3)
		(in millions)
	Assets:
	Commodity derivatives	$	—			$	157			$	—			$	157

	Interest rate derivatives	—				10				—				10

	Deferred compensation plan assets	64				—				—				64

	Total assets	64				167				—				231

	Liabilities:
	Commodity derivatives	—				12				—				12

	Interest rate derivatives	—				10				—				10

	Total liabilities	—				22				—				22

	Total recurring fair value measurements	$	64			$	145			$	—			$	209

	Commodity derivatives. The Company's commodity derivatives represent oil, 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 which 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.
Deferred compensation plan assets. 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 December 31, 2014 and 2013, the significant inputs to these asset exchange values represented Level 1 independent active exchange market price inputs.
Interest rate derivatives. The Company's interest rate derivative assets and liabilities as of December 31, 2014 and 2013 represent Treasury rate swap contracts and interest rate swap contracts, respectively. 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 December 31, 2014 and 2013 are based on (i) the contracted notional amounts, (ii) London Interbank Offered Rate ("LIBOR") yield curves provided by counterparties and corroborated with forward active market-quoted LIBOR yield curves and (iii) the applicable credit-adjusted risk-free rate yield curve. The Company's interest rate derivative asset and liability measurements represent Level 2 inputs in the hierarchy priority.
Assets and liabilities measured at fair value on a nonrecurring basis. Certain assets and liabilities are measured at fair value on a nonrecurring basis. These assets and liabilities are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances. These assets and liabilities can include inventory, proved and unproved oil and gas properties and other long-lived assets that are written down to fair value when they are impaired or held for sale.
Inventories. During the years ended December 31, 2014 and 2013, the Company recognized impairment charges of $8 million and $23 million, respectively, primarily to reduce the carrying value of its excess well pipe inventory. The Company calculated the estimated fair value of the inventory using significant Level 2 assumptions based on third-party price quotes for the asset in an active market. The impairment charges are included in other expense in the Company's accompanying consolidated statements of operations.
Proved oil and gas properties. During 2013 and 2012, reductions in Management's Price Outlooks provided indications of possible impairment of the Company's predominately dry gas properties in the Raton field in southeastern Colorado and the Barnett Shale field in North Texas. As a result of management's assessments, during the years ended December 31, 2013 and 2012, the Company recognized impairment charges to reduce the carrying values of the Raton field and the Barnett Shale field, respectively, to their estimated fair values. The impairment charge associated with the Barnett Shale field is reported in loss from discontinued operations, net of tax in the accompanying consolidated statements of operations.
The Company calculated the fair values of the Raton field and the Barnett Shale field proved properties using a discounted cash flow model. Significant Level 3 assumptions associated with the calculation of discounted future cash flows included Management's Price Outlooks and management's outlooks for (i) production costs, (ii) capital expenditures, (iii) production and (iv) estimated proved reserves and risk-adjusted probable reserves. Management's Price Outlooks are developed based on third-party longer-term commodity futures price outlooks as of each measurement date. The expected future net cash flows were discounted using an annual rate of 10 percent to determine fair value.
The following table presents the fair value and fair value adjustments (in millions) for the Company's 2013 and 2012 proved property impairments, as well as the average oil price per barrel ("Bbl") and gas price per British thermal unit ("MMBtu") utilized in respective Management's Price Outlooks:


		Year ended		Fair				Fair Value				Management's Price Outlooks
		December 31,		Value				Adjustment				Oil				Gas

Barnett Shale		2012		$	185			$	(533	)		$	87.09			$	4.78

Raton		2013		$	534			$	(1,495	)		$	80.4			$	4.43

It is reasonably possible that the estimate of undiscounted future net cash flows attributable to these or other properties may change in the future resulting in the need to impair their carrying values. The primary factors that may affect estimates of future cash flows are (i) future adjustments, both positive and negative, to proved and appropriate risk-adjusted probable and possible oil and gas reserves, (ii) results of future drilling activities, (iii) Management's Price Outlooks and (iv) increases or decreases in production and capital costs associated with these fields.
Assets associated with divestitures. Long-lived assets that are classified as held for sale are recorded at the lower of the asset's net carrying amount or estimated fair value less costs to sell. At December 31, 2013, the Sendero assets, Pioneer Alaska and the Barnett Shale field assets were classified as held for sale and carried as such until their divestitures in March 2014, April 2014 and September 2014, respectively. Beginning in the third quarter of 2014, the Hugoton field assets were classified as held for sale until their divestiture in September 2014. At December 31, 2013, the fair value of the Barnett Shale field assets was based upon a weighted average calculation that utilized management inputs for both an estimated sales price and a discounted cash flow model for the proved properties using Level 3 assumptions as discussed in the proved oil and gas properties section above, while Sendero and Pioneer Alaska fair values were each based solely on estimated sales prices, less costs to sell. During 2014, the fair value measurements of all assets classified as held for sale were based on their sales prices, less costs to sell. See Note C for additional information regarding the Company's divestitures.
The following table presents the fair value adjustments made by the Company during the years ended December 31, 2014 and 2013 related to assets associated with divestitures:


				Year Ended December 31, 2014								Year Ended December 31, 2013
		Classification		Estimated Fair Value Less Costs to Sell				Fair Value Adjustment				Estimated Fair Value Less Costs to Sell				Fair Value Adjustment
				(in millions)
Sendero		Continuing operations										$	31			$	(25	)

Pioneer Alaska		Discontinued operations		$	253			$	(97	)		$	351			$	(539	)

Barnett Shale field		Discontinued operations		$	149			$	(174	)		$	180			$	(190	)

Hugoton field		Discontinued operations		$	328			$	(34	)

Unproved oil and gas properties. During December 2014 and 2012, the Company recorded impairment charges of $50 million and $72 million to reduce the carrying value of unproved properties in southeast Colorado (reported in exploration and abandonments in the accompanying consolidated statements of operations) and the Barnett Shale field (reported in loss from discontinued operations, net of tax in the accompanying consolidated statements of operations), respectively. The Company calculated the estimated fair values of the unproved acreage in southeast Colorado and in the Barnett Shale field using significant Level 3 assumptions based on average lease bonuses per acre for its prospective acreage. No value was allocated to acreage that the Company does not plan to develop in southeast Colorado and in the Barnett Shale field.
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 December 31, 2014 and 2013 are as follows:



		31-Dec-14								31-Dec-13
		Carrying				Fair				Carrying				Fair
		Value				Value				Value				Value
		(in millions)
Long-term debt		$	2,665			$	2,938			$	2,653			$	3,019

Long-term debt includes the Company's 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 credit facility is 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 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 assets acquired and liabilities assumed in a business combination, goodwill and asset retirement obligations.
Concentrations of credit risk. As of December 31, 2014, the Company's primary concentration of credit risks are the risks of collecting accounts receivable – trade and the risk of counterparties' failure to perform under derivative obligations. See Note L for information regarding the Company's major customers.
The Company has entered into International Swap Dealers Association Master Agreements ("ISDA Agreements") with each of its derivative counterparties. The terms of the ISDA Agreements provide the Company and the counterparties with rights of set off upon the occurrence of defined acts of default by either the Company or a counterparty to a derivative, whereby the party not in default may set off all derivative liabilities owed to the defaulting party against all derivative asset receivables from the defaulting party. See Note E for additional information regarding the Company's derivative activities and information regarding derivative net assets and liabilities by counterparty.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	NOTE E. 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 associated with the Company's outstanding oil derivative contracts as of December 31, 2014 and the weighted average oil prices for those contracts:



		2015				2016
	Swap contracts:
	Volume (Bbls)	82,000				—

	Price per Bbl	$	71.18			$	—

	Collar contracts with short puts:
	Volume (Bbls) (a)(b)	13,767				73,000

	Price per Bbl:
	Ceiling	$	101.36			$	96.46

	Floor	$	86.82			$	85.47

	Short put	$	75.73			$	74.35

	Rollfactor swap contracts:
	Volume (Bbl)	36,575				—

	NYMEX roll price (c)	$	0.06			$	—

	____________________

	(a)	Counterparties have the option to extend for an additional year 5,000 Bbls per day of 2015 collar contracts with short puts with a ceiling price of $100.08 per Bbl, a floor price of $90.00 per Bbl and a short put price of $80.00 per Bbl. The option to extend is exercisable on December 31, 2015. These contracts give the counterparties the option to extend the contracts under the same terms for an additional year if the option to extend is exercised by the counterparties on December 31, 2015.
	(b) During the period from January 1, 2015 through February 13, 2015, the Company converted (i) 3,000 Bbls per day of 2015 collar contracts with short puts into new 2015 collar contract with short puts with a ceiling price of $78.33 per Bbl, a floor price of $66.50 per Bbl and a short put price of $40.00 per Bbl and (ii) 55,000 Bbls per day of 2016 collar contracts with short puts into new 2016 collar contracts with short puts with a ceiling price of $77.41 per Bbl, a floor price of $66.58 per Bbl and a short put price of $41.55 per Bbl.

	(c)	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.
	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 component product posted prices. The Company uses derivative contracts to manage the NGL component product price volatility.
	The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of December 31, 2014 and the weighted average NGL prices for those contracts:


		2015				2016
	Swap contracts:
	Volume (Bbl) (a)	—				4,000

	Average price per Bbl:	$	—			$	12.29

	____________________

	(a)	Represent derivative contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
	During the period from January 1, 2015 through February 13, 2015, the Company entered into (i) 5,000 Bbls per day of swap contracts for ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices for February through December 2015 with a fixed price of $7.83 per Bbl, (ii) 500 Bbls per day of swap contracts for ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices for March through December 2015 with a fixed price of $7.56 per Bbl, (iii) 8,500 Bbls per day of swap contracts for propane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices for February through December 2015 with a fixed price of $21.48 per Bbl and (iv) 2,000 Bbls per day of swap contracts for propane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices for 2016 with a fixed price of $21.63 per Bbl.
	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 associated with the Company's outstanding gas derivative contracts as of December 31, 2014 and the weighted average gas prices for those contracts:



		2015				2016				2017
	Swap contracts:
	Volume (MMBtu)	20,000				70,000				—

	Price per MMBtu	$	4.31			$	4.06			$	—

	Collar contracts with short puts:
	Volume (MMBtu)	285,000				20,000				—

	Price per MMBtu:
	Ceiling	$	5.07			$	5.36			$	—

Floor	$	4			$	4			$	—

Short put	$	3			$	3			$	—

Basis swap contracts:
Gulf Coast basis swap contracts (a)	20,000				—				—

Price differential ($/MMBtu)	$	—			$	—			$	—

Mid-Continent index swap volume (a)	95,000				15,000				30,000

Price differential ($/MMBtu)	$	(0.24	)		$	(0.32	)		$	(0.34	)
Permian Basin index swap volume (a)	10,000				—				—

Price differential ($/MMBtu)	$	(0.13	)		$	—			$	—

____________________

(a)	Represent swaps that fix the basis differentials between the index prices at which the Company sells its Gulf Coast, Mid-Continent and Permian Basin gas, respectively, and the NYMEX Henry Hub index price used in gas swap and collar contracts.
Marketing and basis differential derivatives activities. Periodically, the Company enters into buy and sell marketing arrangements to fulfill firm pipeline transportation commitments. Associated with these marketing arrangements, the Company may enter into index swaps to mitigate price risk. As of December 31, 2014, the Company had oil index swap contracts totaling 10,000 Bbls per day for 2015 with a price differential of $2.99 per Bbl between Cushing WTI and Louisiana Light Sweet.
Interest rate derivative activities. During the second quarter of 2014, the Company terminated its interest rate derivative contracts for cash proceeds of $14 million. Prior to termination, the Company received a fixed interest rate of 3.95 percent in exchange for paying a floating interest rate comprised of the three-month London Interbank Offered Rate ("LIBOR") plus an average rate of 1.11 percent on a notional amount of $400 million.
As of December 31, 2014, the Company was a party to (i) interest rate derivative contracts that expire on June 30, 2015 for a notional amount of $200 million and (ii) interest rate derivative contracts that expire on September 15, 2015 for a notional amount of $100 million. The Company will pay an average fixed rate of 2.43 percent and 2.46 percent, respectively, in exchange for receiving the 10-year Treasury rate as of the expiration date.
During the period from January 1, 2015 through February 13, 2015, the Company entered into additional interest rate derivative contracts that expire on September 15, 2015 for a notional amount of $50 million. The Company will pay an average fixed rate of 2.20 percent in exchange for receiving the 10-year Treasury rate as of the expiration date.
Tabular disclosure of derivative financial instruments. All of the Company's derivatives are accounted for as non-hedge derivatives as of December 31, 2014 and December 31, 2013 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 December 31, 2014
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 millions)
Derivatives not designated as hedging instruments
Asset Derivatives:
Commodity price derivatives		Derivatives - current		$	579			$	(1	)		$	578

Commodity price derivatives		Derivatives - noncurrent		$	182			$	(1	)		181

												$	759

Liability Derivatives:
Commodity price derivatives		Derivatives - current		$	1			$	(1	)		$	—

Interest rate derivatives		Derivatives - current		3				$	—			3

Commodity price derivatives		Derivatives - noncurrent		$	3			$	(1	)		2

												$	5




Fair Value of Derivative Instruments as of December 31, 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 millions)
Derivatives not designated as hedging instruments
Asset Derivatives:
Commodity price derivatives		Derivatives - current		$	73			$	(7	)		$	66

Interest rate derivatives		Derivatives - current		$	10			$	—			10

Commodity price derivatives		Derivatives - noncurrent		$	95			$	(4	)		91

Interest rate derivatives		Derivatives - noncurrent		$	15			$	(15	)		—

												$	167

Liability Derivatives:
Commodity price derivatives		Derivatives - current		$	19			$	(7	)		$	12

Commodity price derivatives		Derivatives - noncurrent		$	4			$	(4	)		—

Interest rate derivatives		Derivatives - noncurrent		$	25			$	(15	)		10

												$	22


The following table details the location of gains and losses reclassified from AOCI-Hedging into earnings on the Company's discontinued cash flow hedging contracts in the accompanying consolidated statements of operations:


Derivatives in Cash Flow Hedging Relationships		Location of Gain/(Loss)		Amount of Gain/(Loss) Reclassified
		Reclassified from AOCI		from AOCI into Earnings
		into Earnings		Year Ended December 31,
				2014				2013				2012
				(in millions)
Commodity price derivatives		Oil and gas revenue		$	—			$	—			$	(3	)

Interest rate derivatives		Interest expense		—				—				(2		)

Total				$	—			$	—			$	(5	)


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 Instruments		Location of Gain/(Loss)		Amount of Gain/(Loss) Recognized in
		Recognized in Earnings on Derivatives		Earnings on Derivatives
				Year Ended December 31,
				2014				2013				2012
				(in millions)
Commodity price derivatives		Derivative gains, net		$	697			$	(6	)		$	353

Interest rate derivatives		Derivative gains, net		15				10				(23		)

Total				$	712			$	4			$	330

Derivative counterparties. 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 provides the Company's net derivative assets or liabilities by counterparty as of December 31, 2014:



	Net Assets
	(in millions)
JP Morgan Chase	$	130

J. Aron & Company	120

Merrill Lynch	101

Citibank, N.A.	98

Morgan Stanley	69

BMO Financial Group	47

Barclays Capital	45

Wells Fargo Bank, N.A.	44

Societe Generale	39

Macquarie Bank	19

Credit Suisse	18

Toronto Dominion	12

Den Norske Bank	11

Royal Bank of Canada	1

Total	$	754

Exploratory_Well_Costs

Exploratory Well Costs	12 Months Ended
	Dec. 31, 2014
Capitalized Exploratory Well Costs [Abstract]
Exploratory Well Costs	NOTE F. Exploratory Well 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. 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 each of the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Beginning capitalized exploratory well costs	$	159		$	213		$	108

	Additions to exploratory well costs pending the determination of proved reserves	1,860			1,220			926

	Reclassification due to determination of proved reserves	(1,628		)	(1,045		)	(790		)
	Disposition of assets sold	(47		)	(93		)	—

	Impairment of properties	(13		)	(87		)	—

	Exploratory well costs charged to exploration and abandonment expense (a)	(26		)	(49		)	(31		)
	Ending capitalized exploratory well costs (b)	$	305		$	159		$	213

	_______________

	(a)	Includes exploration and abandonment expense of $43 million and $22 million in 2013 and 2012, respectively, that is included in discontinued operations for each respective period in the accompanying consolidated statements of operations.

	(b)	The December 31, 2013 balance includes $60 million of capitalized exploratory well costs classified as held for sale in the accompanying consolidated balance sheet as of December 31, 2013.
	The following table provides an aging, as of December 31, 2014, 2013 and 2012 of capitalized exploratory costs and the number of projects for which exploratory well costs have been capitalized for a period greater than one year, based on the date drilling was completed:



		As of December 31,
		2014			2013			2012
		(in millions, except well counts)
	Capitalized exploratory well costs that have been suspended:
	One year or less	$	305		$	116		$	191

	More than one year	—			43			22

		$	305		$	159		$	213

	Number of projects with exploratory well costs that have been suspended for a period greater than one year	—			1			1

	The $43 million and $22 million of suspended well costs that were suspended for a period greater than one year at December 31, 2013 and December 31, 2012, respectively, related to Pioneer Alaska, which was sold in April 2014. See Note C for additional information on the sale of Pioneer Alaska.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long-Term Debt	NOTE G. Long-term Debt and Interest Expense
	Long-term debt, including the effects of issuance discounts and net deferred fair value hedge losses, consisted of the following components at December 31, 2014 and 2013:



		December 31,
		2014				2013
		(in millions)
	Outstanding debt principal balances:
	5.875% senior notes due 2016	$	455			$	455

	6.65% senior notes due 2017	485				485

	6.875 % senior notes due 2018	450				450

	7.500 % senior notes due 2020	450				450

	3.95% senior notes due 2022	600				600

	7.20% senior notes due 2028	250				250

		2,690				2,690

	Issuance discounts	(24		)		(36		)
	Net deferred fair value hedge losses	(1		)		(1		)
	Total long-term debt	$	2,665			$	2,653

	Credit facility. The Company maintains a revolving credit agreement (the "Credit Facility") with a syndicate of financial institutions with aggregate loan commitments of $1.5 billion that expire in December 2017. As of December 31, 2014, the Company had no outstanding borrowings under the Credit Facility.
	Borrowings under the Credit Facility may be in the form of revolving loans or swing line loans. Aggregate outstanding swing line loans may not exceed $150 million. Revolving loans under the Credit Facility bear interest, at the option of the Company, based on (a) a rate per annum equal to the higher of the prime rate announced from time to time by Wells Fargo Bank, National Association or the weighted average of the rates on overnight Federal funds transactions with members of the Federal Reserve System during the last preceding business day plus 0.5 percent plus a defined alternate base rate spread margin, which is currently 0.5 percent based on the Company's debt rating or (b) a base Eurodollar rate, substantially equal to LIBOR, plus a margin (the "Applicable Margin"), which is currently 1.50 percent and is also determined by the Company's debt rating. Swing line loans under the Credit Facility bear interest at a rate per annum equal to the "ASK" rate for Federal funds periodically published by the Dow Jones Market Service plus the Applicable Margin. Letters of credit outstanding under the Credit Facility are subject to a per annum fee, representing the Applicable Margin plus 0.125 percent. The Company also pays commitment fees on undrawn amounts under the Credit Facility that are determined by the Company's debt rating (currently 0.25 percent). Borrowings under the Credit Facility are general unsecured obligations.
	The Credit Facility requires the maintenance of a ratio of total debt to book capitalization, subject to certain adjustments, not to exceed .60 to 1.0. As of December 31, 2014, the Company was in compliance with all of its debt covenants.
	Senior notes. The Company's senior notes are general unsecured obligations ranking equally in right of payment with all other senior unsecured indebtedness of the Company and are senior in right of payment to all existing and future subordinated indebtedness of the Company. The Company is a holding company that conducts all of its operations through subsidiaries; consequently, the senior notes are structurally subordinated to all obligations of its subsidiaries. Interest on the Company's senior notes is payable semiannually.
	Convertible senior notes. As of December 31, 2012, the Company had $480 million of 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. 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 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 million of cash and issued to the tendering holders 4.4 million shares of the Company's common stock in accordance with the terms of the Convertible Senior Notes indenture agreement. On May 16, 2013, the Company paid $1 million in principal and interest to redeem all Convertible Senior Notes that remained outstanding.
	For the years ended December 31, 2013 and 2012, the Company recorded $9.4 million and $33.5 million, respectively, of interest expense relating to the Convertible Senior Notes, which had an effective interest rate of 6.75 percent.
	Principal maturities. Principal maturities of long-term debt at December 31, 2014, are as follows (in millions):



	2015	$	—

	2016	$	455

	2017	$	485

	2018	$	450

	2019	$	—

	Thereafter	$	1,300

	Interest expense. The following amounts have been incurred and charged to interest expense for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions)
	Cash payments for interest	$	193			$	183			$	168

	Amortization of issuance discounts	12				12				28

	Amortization of net deferred hedge losses (a)	—				—				2

	Amortization of capitalized loan fees	5				5				6

Net changes in accruals	(22		)		(6		)		11

Interest incurred	188				194				215

Less capitalized interest	(4		)		(10		)		(11		)
Total interest expense	$	184			$	184			$	204

_______________

(a)	Includes interest rate derivative hedges of $2 million for the period ended December 31, 2012 that were reclassified from AOCI - Hedging into earnings upon expiration (see Note E).

Incentive_Plans

Incentive Plans	12 Months Ended
Incentive Plans	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Compensation and Employee Benefit Plans [Text Block]	NOTE H. Incentive Plans
	Deferred compensation retirement plan. In August 1997, the Compensation Committee of the Company's board of directors (the "Board") approved a deferred compensation retirement plan for the officers and certain key employees of the Company. Each officer and key employee is allowed to contribute up to 25 percent of their base salary and 100 percent of their annual bonus. The Company will provide a matching contribution of 100 percent of the officer's and key employee's contribution limited to the first ten percent of the officer's base salary and eight percent of the key employee's base salary. The Company's matching contribution vests immediately. A trust fund has been established by the Company to accumulate the contributions made under this retirement plan. The Company's matching contributions were $3 million, $3 million and $2 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	401(k) plan. The Pioneer Natural Resources USA, Inc. ("Pioneer USA," a wholly-owned subsidiary of the Company) 401(k) and Matching Plan (the "401(k) Plan") is a defined contribution plan established under the Internal Revenue Code Section 401. All regular full-time and part-time employees of Pioneer USA are eligible to participate in the 401(k) Plan on the first day of the month following their date of hire. Participants may contribute an amount up to 80 percent of their annual salary into the 401(k) Plan. Matching contributions are made to the 401(k) Plan in cash by Pioneer USA in amounts equal to 200 percent of a participant's contributions to the 401(k) Plan that are not in excess of five percent of the participant's base compensation (the "Matching Contribution"). Each participant's account is credited with the participant's contributions, Matching Contributions and allocations of the 401(k) Plan's earnings. Participants are fully vested in their account balances except for Matching Contributions and their proportionate share of 401(k) Plan earnings attributable to Matching Contributions, which proportionately vest over a four-year period that begins with the participant's date of hire. During the years ended December 31, 2014, 2013 and 2012, the Company recognized compensation expense of $33 million, $30 million and $25 million, respectively, as a result of Matching Contributions.
	Stock-based compensation costs. In accordance with GAAP, the Company records stock-based compensation expense ratably over the vesting periods of the Company's stock-based compensation awards using the awards' fair value. The Company maintains three plans providing for stock-based compensation, the Pioneer Long-Term Incentive Plan ("LTIP"), the Pioneer 2008 PSE Employee Long-Term Incentive Plan ("PSE LTIP") and the Company's Employee Stock Purchase Plan ("ESPP").
	Pioneer Long-Term Incentive Plan. The LTIP provides for the granting of various forms of awards, including stock options, stock appreciation rights, performance units, restricted stock and restricted stock units to directors, officers and employees of the Company. The shares to be delivered under the LTIP shall be made available from (i) authorized but unissued shares, (ii) shares held as treasury stock or (iii) previously issued shares reacquired by the Company, including shares purchased on the open market. The following table shows the number of shares available for issuance pursuant to awards under the Company's LTIP at December 31, 2014:



	Approved and authorized awards	9,100,000
	Approved and authorized awards	9,100,000
	Awards issued after May 3, 2006	(6,738,082	)
	Awards available for future grant	2,361,918
	Awards available for future grant	2,361,918
	Pioneer 2008 PSE Employee Long-Term Incentive Plan. The PSE LTIP was adopted by Pioneer Southwest in May 2008. The plan, along with all of Pioneer Southwest's obligations under outstanding awards, was assumed by the Company in connection with the Company's acquisition of all outstanding common units of Pioneer Southwest not owned by the Company in December 2013, at which time the plan's name was changed. The only outstanding awards under the PSE LTIP at the time of the acquisition were phantom units of Pioneer Southwest, all of which were converted into restricted stock units of the Company, and no awards have been granted under the PSE LTIP since the Company's assumption of the plan. The PSE LTIP provides for the granting of various forms of awards, including stock options, stock appreciation rights, performance units, restricted stock and other stock-based awards to directors, officers and employees of the Company. The shares to be delivered under the PSE LTIP shall be made available from (i) authorized but unissued shares, (ii) shares held as treasury stock or (iii) previously issued shares reacquired by the Company, including shares purchased on the open market. The following table shows the number of Pioneer common shares available for issuance pursuant to awards under the PSE LTIP at December 31, 2014:



	Approved and authorized awards	678,034
	Approved and authorized awards	678,034
	Awards issued under the PSE LTIP	(23,192	)
	Awards available for future grant	654,842
	Awards available for future grant	654,842

	Employee Stock Purchase Plan. The Company has an ESPP that allows eligible employees to annually purchase the Company's common stock at a discounted price. Officers of the Company are not eligible to participate in the ESPP. Contributions to the ESPP are limited to 15 percent of an employee's pay (subject to certain ESPP limits) during the eight-month offering period (January 1 to August 31). Participants in the ESPP purchase the Company's common stock at a price that is 15 percent below the closing sales price of the Company's common stock on either the first day or the last day of each offering period, whichever closing sales price is lower. The following table shows the number of shares available for issuance under the ESPP at December 31, 2014:



	Approved and authorized shares	1,250,000
	Approved and authorized shares	1,250,000
	Shares issued	(774,638	)
	Shares available for future issuance	475,362
	Shares available for future issuance	475,362
	The following table reflects stock-based compensation expense recorded for each type of stock-based compensation award and the associated income tax benefit for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions)
	Restricted stock-Equity Awards	$	65			$	57			$	50
	Restricted stock-Equity Awards	$	65			$	57			$	50
	Restricted stock-Liability Awards	28				40				23
	Restricted stock-Liability Awards	28				40				23
	Stock options (a)	2				3				4
	Stock options (a)	2				3				4
	Performance unit awards	13				9				6
	Performance unit awards	13				9				6
	ESPP	2				2				2
	ESPP	2				2				2
	Other	—				1				1
	Other	—				1				1
	Total	$	110			$	112			$	86
	Total	$	110			$	112			$	86
	Income tax benefit	$	33			$	36			$	28
	Income tax benefit	$	33			$	36			$	28
	_____________________

	(a)	Cash proceeds received from stock option exercises during 2014, 2013 and 2012 amounted to $6 million, $5 million and $3 million, respectively.
	As of December 31, 2014, there was $122 million of unrecognized stock-based compensation expense related to unvested share-based compensation plans, including $25 million attributable to Liability Awards. The stock-based compensation expense will be recognized on a straight-line basis over the remaining vesting periods of the awards, which is a period of less than three years on a weighted average basis.
	Restricted stock awards. During 2014, the Company awarded 546,710 restricted shares or units of the Company's common stock as compensation to directors, officers and employees of the Company (including 140,093 shares or units representing Liability Awards). The Company's issued shares, as reflected in the consolidated balance sheet as of December 31, 2014, do not include 170,210 of issued, but unvested shares awarded under stock-based compensation plans that have voting rights.
	The following table reflects the restricted stock award activity for the year ended December 31, 2014:



	Equity Awards							Liability Awards
	Number of			Weighted				Number of Shares
	Shares			Average Grant-
				Date Fair
				Value
Outstanding at beginning of year	1,371,207			$	117.09			422,382
Outstanding at beginning of year	1,371,207			$	117.09			422,382
Shares granted	406,617			$	184.39			140,093
Shares granted	406,617			$	184.39			140,093
Shares forfeited	(79,777	)		$	134.25			(33,052	)
Shares forfeited	(79,777	)		$	134.25			(33,052	)
Shares vested	(464,508	)		$	108.79			(201,336	)
Shares vested	(464,508	)		$	108.79			(201,336	)
Outstanding at end of year	1,233,539			$	140.57			328,087
Outstanding at end of year	1,233,539			$	140.57			328,087
The weighted average grant-date fair value of restricted stock equity awards awarded during 2014, 2013 and 2012 was $184.39, $134.17 and $113.09, respectively. The fair value of shares for which restrictions lapsed during 2014, 2013 and 2012 was $88 million, $69 million and $137 million, respectively, based on the market price on the vesting date.
As of December 31, 2014 and 2013, accounts payable – due to affiliates in the accompanying consolidated balance sheets includes $23 million and $33 million of liabilities attributable to the Liability Awards, representing the earned portion of the fair value of the outstanding awards as of that date. The fair value of Liability Awards for which restrictions lapsed during 2014, 2013 and 2012 was $38 million, $26 million and $14 million respectively, based on the market price on the vesting date.
Stock option awards. Certain employees may be granted options to purchase shares of the Company's common stock with an exercise price equal to the fair market value of Pioneer common stock on the date of grant. The fair value of stock option awards is determined using the Black-Scholes option-pricing model. Option awards have a ten-year contract life. The expected life of an option is estimated based on historical and expected exercise behavior. The volatility assumption was estimated based upon expectations of volatility over the life of the option as measured by historical volatility. The risk-free interest rate was based on the United States Treasury rate for a term commensurate with the expected life of the option. The dividend yield was based upon a seven-year average dividend yield.
The Company did not grant any stock options during the years ended December 31, 2014 and 2013. The Company used the following weighted-average assumptions to estimate the fair value of stock options granted during the year ended December 31, 2012:



	2012
Expected option life - years	7
Expected option life - years	7
Volatility	49.4	%
Risk-free interest rate	1.5	%
Dividend yield	0.4	%

A summary of the Company's nonstatutory stock option awards activity for the year ended December 31, 2014 is presented below:



	Number			Weighted				Weighted		Aggregate
	of Shares			Average				Average		Intrinsic Value
				Exercise Price				Remaining
								Contractual
								Life
								(in years)		(in millions)
Outstanding at beginning of year	289,927			$	74.9
Outstanding at beginning of year	289,927			$	74.9
Options exercised	(90,869	)		$	69.19
Options exercised	(90,869	)		$	69.19
Outstanding at end of year	199,058			$	77.51			5.96		$	14
Outstanding at end of year	199,058			$	77.51			5.96		$	14
Exercisable at end of year	106,278			$	45.86			4.92		$	11
Exercisable at end of year	106,278			$	45.86			4.92		$	11
The weighted average grant-date fair value of options awarded during 2012 was $56.29 using the Black-Scholes option-pricing model. The intrinsic value of options exercised during 2014, 2013 and 2012 was $12 million, $21 million and $17 million, respectively, based on the difference between the market price at the exercise date and the option exercise price.
Performance unit awards. During 2014, 2013 and 2012, the Company awarded performance units to certain of the Company's officers under the LTIP. The number of shares of common stock to be issued is determined by comparing the Company's total shareholder return to the total shareholder return of a predetermined group of peer companies over the performance period. The performance unit awards vest over a 34-month service period. The grant-date fair values per unit of the 2014, 2013 and 2012 performance unit awards were $232.20, $189.23 and $172.57, respectively, which amounts were determined using the Monte Carlo simulation method and are being recognized as stock-based compensation expense ratably over the performance period. The Monte Carlo simulation model utilizes multiple input variables that determine the probability of satisfying the market condition stipulated in the award grant and calculates the fair value of the award. Expected volatilities utilized in the model were estimated using a historical period consistent with the remaining performance period of approximately three years. The risk-free interest rate was based on the United States Treasury rate for a term commensurate with the expected life of the grant. The Company used the following assumptions to estimate the fair value of performance unit awards granted during 2014, 2013 and 2012:



	2014					2013					2012
Risk-free interest rate	0.62%					0.40%					0.40%
Range of volatilities	29	%	-	41.50%		30.4	%	-	42.90%		33.6	%	-	49.00%
The following table summarizes the performance unit activity for the year ended December 31, 2014:



	Number of			Weighted Average
	Units (a)			Grant-Date
				Fair Value
Beginning performance unit awards	134,476			$	183.66
Beginning performance unit awards	134,476			$	183.66
Units granted	67,182			$	232.2
Units granted	67,182			$	232.2
Units forfeited	(1,153	)		$	189.23
Units forfeited	(1,153	)		$	189.23
Units vested (b)	(45,772	)		$	172.87
Units vested (b)	(45,772	)		$	172.87
Ending performance unit awards	154,733			$	207.88
Ending performance unit awards	154,733			$	207.88
_____________________

(a)	These amounts reflect the number of performance units granted. The actual payout of shares may be between zero percent and 250 percent of the performance units granted depending upon the total shareholder return ranking of the Company compared to peer companies at the vesting date.

(b)	On December 31, 2014, the service period lapsed on 44,949 of these performance unit awards, which does not include 823 retirement deferred shares scheduled for release on December 31, 2015. The lapsed units earned two shares for each vested award representing 89,898 aggregate shares of common stock issued on January 2, 2015.
The fair value of shares for which restrictions lapsed during 2014, 2013 and 2012 was $13 million, $19 million and $19 million, respectively, based on the market price on the vesting date.

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	NOTE I. Asset Retirement Obligations
	The Company's asset retirement obligations primarily relate to the future plugging and abandonment of wells and related facilities. Market risk premiums associated with asset retirement obligations are estimated to represent a component of the Company's credit-adjusted risk-free rate that is utilized in the calculations of asset retirement obligations. The following table summarizes the Company's asset retirement obligation activity during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Beginning asset retirement obligations	$	194		$	198		$	137

	Obligations assumed in acquisitions	6			—			10

	New wells placed on production	5			6			10

	Changes in estimates (a)	7			8			52

	Disposition of wells	(14		)	(16		)	(2		)
	Obligations settled	(21		)	(15		)	(18		)
	Accretion of discount on continuing operations	12			12			8

	Accretion of discount on discontinued operations	—			1			1

	Ending asset retirement obligations	$	189		$	194		$	198

	_____________________

	(a)	The changes in the 2014, 2013 and 2012 estimates are primarily due to increases in abandonment cost estimates based on recent actual costs incurred to abandon wells and declines in the credit-adjusted risk-free discount rates used to value the Company's asset retirement obligations. The increases in the 2014 and 2012 estimates were further impacted by declines in oil, NGL and gas prices used to calculate proved reserves, which had the effect of shortening the economic life of certain wells and increasing the present value of future retirement obligations. The increases in 2013 estimates were partially offset by higher commodity prices, which had the effect of lengthening the economic life of certain wells and decreasing the present value of future retirement obligations.
	As of December 31, 2014 and 2013, the current portions of the Company's asset retirement obligations were $28 million and $19 million, respectively.

Commitments_And_Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	NOTE J. Commitments and Contingencies
	Severance agreements. The Company has entered into severance and change in control agreements with its officers and certain key employees. The current annual salaries for the officers and key employees covered under such agreements total $41 million.
	Indemnifications. The Company has agreed to indemnify its directors and certain of its officers, employees and agents with respect to claims and damages arising from acts or omissions taken in such capacity, as well as with respect to certain litigation.
	Legal actions. The Company is party to various 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 these 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.
	Obligations following divestitures. In connection with its divestiture transactions, the Company may retain certain liabilities and provide the purchaser certain indemnifications, subject to defined limitations, which may apply to identified pre-closing matters, including matters of litigation, environmental contingencies, royalty obligations and income taxes. These retention and indemnification arrangements were undertaken by the Company with respect to some or all of such pre-closing matters in connection with the sale of its Argentine assets in 2006, the sale of its Canadian assets in 2007, the sale of Pioneer Tunisia in February 2011, the sale of Pioneer South Africa in August 2012, and the sale of Pioneer Alaska and the Company's Hugoton and Barnett Shale assets in 2014, as well as in connection with sales of joint interests. The Company does not believe that these obligations are probable of having a material impact on its liquidity, financial position or future results of operations.
	Drilling commitments. The Company periodically enters into contractual arrangements under which the Company is committed to expend funds to drill wells in the future. The Company also enters into agreements to secure drilling rig services, which require the Company to make future minimum payments to the rig operators. The Company records drilling commitments in the periods in which the well is drilled or rig services are performed. Future minimum drilling commitments at December 31, 2014 are as follows (in millions):


	2015	$	303

	2016	$	197

	2017	$	113

	2018	$	32

	2019	$	2

	Thereafter	$	—

	Lease agreements. The Company leases equipment and office facilities under operating leases. Rent expense for the years ended December 31, 2014, 2013 and 2012 was $66 million, $58 million and $48 million, respectively. These payments include $9 million, $10 million and $8 million associated with discontinued operations for the years ended December 31, 2014, 2013 and 2012, respectively, which are included in earnings from discontinued operations, net of tax, in the accompanying consolidated statements of operations. Future minimum lease commitments under noncancelable operating leases at December 31, 2014 are as follows (in millions):



	2015	$	30

	2016	$	22

	2017	$	20

	2018	$	19

	2019	$	19

	Thereafter	$	27

	Firm purchase, gathering, processing, transportation and fractionation commitments. The Company from time to time enters into, and as of December 31, 2014 is a party to, take-or-pay agreements, which include contractual commitments to purchase sand and water to accommodate the Company's drilling operations and contractual commitments with midstream service companies and pipeline carriers for future gathering, processing, transportation and fractionation. These commitments are normal and customary for the Company's business activities. Future minimum purchase, gathering, processing, transportation and fractionation commitments at December 31, 2014 are as follows (in millions):



	2015	$	455

	2016	$	486

	2017	$	364

	2018	$	332

	2019	$	325

	Thereafter	$	1,011

	Certain future minimum gathering, processing, transportation and fractionation fees are based upon rates and tariffs subject to change over the lives of the commitments. The above commitments include demand fees associated with volume delivery commitments, principally comprised of approximately 50,000 Bbls per day through August 2017 related to the Company's Permian Basin operations. If the Company does not expect to be able to fulfill its short-term and long-term delivery obligations from projected production of available reserves, the Company expects to purchase third party volumes to satisfy its commitment if it is economical to do so; otherwise, it will pay demand fees for commitment shortfalls.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	NOTE K. Related Party Transactions
	Transactions with affiliated partnerships. Prior to December 2014, the Company, through a wholly-owned subsidiary, served as operator of properties in which it and its affiliated partnerships had an interest. The Company received lease operating and supervision charges in accordance with standard industry operating agreements related to the operation of the properties in which it and its affiliated partnerships had an interest and other fees related to the administration of the affiliated partnerships. For the years ended December 31, 2014, 2013 and 2012, the Company received $3 million, $3 million and $2 million, respectively, associated with these fees.
	In December 2014, the Company acquired the remaining limited partner interests in the affiliated partnerships and caused the partnerships to be merged with and into the Company. Prior to the acquisition, the Company proportionately consolidated the affiliated partnerships.
	*Transactions with EFS Midstream.* The Company, through a wholly-owned subsidiary, owns a noncontrolling interest in its unconsolidated affiliate, EFS Midstream. During the years ended December 31, 2014 and 2013, the Company received $50 million and $25 million, respectively, in distributions from EFS Midstream.
	The Company also (i) provides certain services as the manager of EFS Midstream in accordance with a Master Services Agreement and (ii) is the operator of Eagle Ford Shale properties for which EFS Midstream provides certain services under a Hydrocarbon Gathering and Handling Agreement (the "HGH Agreement").
	Master Services Agreement. The terms of the Master Services Agreement provide that the Company will perform certain manager services for EFS Midstream and be compensated by monthly fixed payments and variable payments attributable to expenses incurred by employees whose time is substantially dedicated to EFS Midstream's business. During 2014, 2013 and 2012, the Company received $3 million, $3 million and $2 million of fixed payments and $18 million, $16 million and $12 million of variable payments, respectively, from EFS Midstream. During 2013, the Company purchased other plant and equipment from EFS Midstream totaling $3 million.
	Hydrocarbon Gathering and Handling Agreement. Under the terms of the HGH Agreement, EFS Midstream is obligated to construct certain equipment and facilities capable of gathering, treating and transporting oil and gas production from the Eagle Ford Shale properties operated by the Company. The HGH Agreement also obligates the Company and its Eagle Ford Shale working interest partners to use the EFS Midstream gathering, treating and transportation equipment and facilities. In accordance with the terms of the HGH Agreement, the Company paid EFS Midstream $103 million, $81 million and $59 million of gathering and treating fees during 2014, 2013 and 2012, respectively. Such amounts were expensed as oil and gas production costs in the accompanying consolidated statements of operations.

Major_Customer

Major Customer	12 Months Ended
Major Customer	Dec. 31, 2014
Concentration Risks, Types, No Concentration Percentage [Abstract]
Major Customers	NOTE L. Major Customers
	The Company's share of oil and gas production is sold to various purchasers who must be prequalified under the Company's credit risk policies and procedures. The Company records allowances for doubtful accounts based on the age of accounts receivables and the financial condition of its purchasers and, depending on facts and circumstances, may require purchasers to provide collateral or otherwise secure their accounts.
	The following purchasers individually accounted for ten percent or more of the Company's consolidated oil, NGL and gas revenues, including the revenues from discontinued operations, in at least one of the three years ended December 31, 2014:



		Year Ended December 31,
		2014		2013		2012
	Plains Marketing LP	24	%	26	%	25	%
	Occidental Energy Marketing Inc.	13	%	12	%	13	%
	Enterprise Products Partners L.P.	11	%	12	%	14	%
	Valero Marketing and Supply Company	10	%	5	%	—	%
	The loss of any of these significant purchasers could have a material adverse effect on the ability of the Company to sell its oil and gas production.

Interest_And_Other_Income

Interest And Other Income	12 Months Ended
	Dec. 31, 2014
Interest and Other Income [Abstract]
Interest And Other Income	NOTE M. Interest and Other Income
	The following table provides the components of the Company's interest and other income during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Equity interest in income of EFS Midstream	$	13		$	7		$	2

	Other income	9			9			6

	Deferred compensation plan income	3			6			2

	Interest income	—			—			1

	Loss from vertical integration services (a)	(16		)	(5		)	(12		)
	Total interest and other income	$	9		$	17		$	(1	)

	______________________

	(a)	Loss from vertical integration services represents net margins, after intercompany gains or losses are eliminated, associated with (i) sales of proppant to third-party customers and providing fracture stimulation and well services to working interest owners in Company-operated properties and (ii) extended idle time activities. For the three years ended December 31, 2014, 2013 and 2012, these net margins include $374 million, $285 million and $248 million of gross vertical integration revenues, respectively and $390 million, $290 million and $260 million of total vertical integration costs and expenses, respectively.

Other_Expense

Other Expense	12 Months Ended
	Dec. 31, 2014
Other Expense [Abstract]
Other Expense	NOTE N. Other Expense
	The following table provides the components of the Company's other expense during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014		2013		2012
		(in millions)
	Transportation commitment charge (a)	$	46	$	39	$	39

	Other	19		16		20

	Terminated drilling rig contract charges (b)	9		1		16

	Impairment of inventory and other property and equipment (c)	8		62		6

	Above market and idle drilling and well services equipment charges (d)	7		10		33

	Contingency and environmental accrual adjustments	—		9		—

	Total other expense	$	89	$	137	$	114

	____________________

	(a)	Primarily represents firm transportation payments on excess pipeline capacity commitments.

	(b)	Primarily represents charges to terminate rig contracts that were not required to meet planned drilling activities.

	(c)	Primarily represents charges of $8 million and $36 million to reduce excess materials and supplies inventories to their market values for the years ended December 31, 2014 and 2013, respectively, and a charge of $25 million for the year ended December 31, 2013 to reduce the carrying value of Sendero to its estimated fair value. See Notes C and D for additional information on the fair value of Sendero and material and supplies inventory, respectively.

	(d)	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that were above market rates and idle drilling rig and fracture stimulation fleet fees, neither of which were chargeable to joint operations.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	NOTE O. Income Taxes
	The Company and its eligible subsidiaries file a consolidated United States federal income tax return. Certain subsidiaries are not eligible to be included in the consolidated United States federal income tax return and separate provisions for income taxes have been determined for these entities or groups of entities. The tax returns and the amount of taxable income or loss are subject to examination by United States federal, state, local and foreign taxing authorities. The Company made current and estimated tax payments of $22 million, $12 million and $32 million (net of tax refunds) during 2014, 2013 and 2012, respectively. These payments and net refunds include tax payments related to Pioneer South Africa's operations of $10 million during 2012.
	The Company continually assesses both positive and negative evidence to determine whether it is more likely than not that deferred tax assets can be realized prior to their expiration. Pioneer monitors Company-specific, oil and gas industry and worldwide economic factors and assesses the likelihood that the Company's net operating loss carryforwards ("NOLs") and other deferred tax attributes in the United States, state, local and foreign tax jurisdictions will be utilized prior to their expiration.
	The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by the taxing authorities, based upon the technical merits of the position. During 2014, the Company recognized a $21 million tax benefit resulting from the resolution of the tax uncertainty related to net operating loss carryovers and alternative minimum tax credits obtained from the 2012 acquisition of Premier Silica. There are no unrecognized tax benefits as of December 31, 2014.
	With respect to income taxes, the Company's policy is to account for interest charges as interest expense and any penalties as other expense in the consolidated statements of operations. The Company files income tax returns in the United States federal jurisdiction, and various state and foreign jurisdictions. As of December 31, 2014, there are no proposed adjustments or uncertain positions in any jurisdiction that would have a significant effect on the Company's future results of operations or financial position. The Company's earliest open years in its key jurisdictions are as follows:



	United States	2013
	Various U.S. states	2009
	South Africa	2009
	The Company's income tax (provision) benefit and amounts separately allocated were attributable to the following items for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions)
	Income tax (provision) benefit from continuing operations	$	(556	)		$	213			$	(288	)

	Income tax (provision) benefit from discontinued operations	$	60			$	249			$	181

	Changes in stockholders' equity:
	Net deferred hedge (loss) gain	$	—			$	—			$	(2	)

	Excess tax benefit related to stock-based compensation	$	19			$	18			$	58

	Tax benefit attributable to conversion of 2.875% senior convertible notes	$	—			$	38			$	—

	Tax benefit attributable to 2013 merger with Pioneer Southwest	$	—			$	200			$	—

	Tax attributable to 2008 Pioneer Southwest initial public offering	$	—			$	—			$	(49	)

	The Company's income tax (provision) benefit attributable to income from continuing operations consisted of the following for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions)
	Current:
	U.S. federal	$	(3	)		$	(11	)		$	(5	)
	U.S. state	(1		)		—				1

		(4		)		(11		)		(4		)
	Deferred:
	U.S. federal	(537		)		208				(270		)

	U.S. state	(15		)		16				(14		)

		(552		)		224				(284		)

	Income tax (provision) benefit from continuing operations	$	(556	)		$	213			$	(288	)

	Reconciliations of the United States federal statutory tax rate to the Company's effective tax rate for income (loss) from continuing operations are as follows for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions, except percentages)
	Income (loss) from continuing operations before income taxes	$	1,597			$	(574	)		$	832

	Less: Net income attributable to noncontrolling interests	—				(39		)		(51		)

Income (loss) from continuing operations attributable to common stockholders before income taxes	1,597				(613		)		781

Federal statutory income tax rate	35		%		35		%		35		%
(Provision) benefit for federal income taxes at the statutory rate	(559		)		215				(273		)

State income tax (provision) benefit (net of federal tax)	(10		)		10				(8		)

Premier Silica benefit	21				—				—

Other	(8		)		(12		)		(7		)
Income tax (provision) benefit from continuing operations	$	(556	)		$	213			$	(288	)

Effective income tax rate, excluding income attributable to the noncontrolling interest	35		%		35		%		37		%
The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities related to continuing operations are as follows as of December 31, 2014 and 2013:



	December 31,
	2014				2013
	(in millions)
Deferred tax assets:
Net operating loss carryforward (a)	$	330			$	329

Asset retirement obligations	68				74

Incentive plans	71				68

Other	74				74

Total deferred tax assets	543				545

Deferred tax liabilities:
Oil and gas properties, principally due to differences in basis, depletion and the deduction of intangible drilling costs for tax purposes	(1,881		)		(1,570		)
Other property and equipment, principally due to the deduction of bonus depreciation for tax purposes	(251		)		(255		)
Net deferred hedge gains	(280		)		(109		)
Other	(95		)		(103		)
Total deferred tax liabilities	(2,507		)		(2,037		)
Net deferred tax liability	$	(1,964	)		$	(1,492	)
Reflected in accompanying consolidated balance sheets as:
Current deferred income tax liability	$	(161	)		$	(19	)
Noncurrent deferred income tax liability	(1,803		)		(1,473		)
Total	$	(1,964	)		$	(1,492	)
____________________

(a)	Net operating loss carryforwards as of December 31, 2014 consist of $927 million of U.S. federal NOLs which expire primarily in 2032 and $120 million of Colorado NOLs which expire between 2027 and 2033.

Net_Income_Loss_Per_Share_Attr

Net Income (Loss) Per Share Attributable To Common Stockholders	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income (Loss) Per Share Attributable To Common Stockholders	NOTE P. Net Income Per Share Attributable To Common Stockholders
	In the calculation of basic net income (loss) per share attributable to common stockholders, participating securities are allocated earnings based on actual dividend distributions received plus a proportionate share of undistributed net income attributable to common stockholders, if any, after recognizing distributed earnings. The Company's participating securities do not participate in undistributed net losses because they are not contractually obligated to do so. The computation of diluted net income (loss) per share attributable to common stockholders reflects the potential dilution that could occur if securities or other contracts to issue common stock that are dilutive were exercised or converted into common stock or resulted in the issuance of common stock that would then share in the earnings of the Company. 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 not be dilutive to net loss per share and conversion into common stock is assumed not to occur. Diluted net income (loss) per share is calculated under both the two-class method and the treasury stock method and the more dilutive of the two calculations is presented.
	The Company's basic net income (loss) per share attributable to common stockholders is computed as (i) net income (loss) attributable to common stockholders, (ii) less participating share- and unit-based basic earnings (iii) divided by weighted average basic shares outstanding. The Company's diluted net income (loss) per share attributable to common stockholders is computed as (i) basic net income (loss) attributable to common stockholders, (ii) plus diluted adjustments to participating undistributed earnings (iii) divided by weighted average diluted shares outstanding.
	The following table is a reconciliation of the Company's net income (loss) attributable to common stockholders to basic and diluted net income (loss) attributable to common stockholders for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013			2012
		(in millions)
	Net income (loss) from continuing operations attributable to common stockholders	$	1,041			$	(400	)	$	493

	Participating basic earnings (a)	(10		)		—			(2		)

	Basic and diluted net income (loss) from continuing operations attributable to common stockholders	1,031				(400		)	491

	Basic and diluted net loss from discontinued operations attributable to common stockholders	(111		)		(438		)	(301		)
	Basic and diluted net income (loss) attributable to common stockholders	$	920			$	(838	)	$	190

	______________________

	(a)	Unvested restricted stock awards and Pioneer Southwest phantom unit awards (prior to the December 2013 Pioneer Southwest merger) represent participating securities because they participate in nonforfeitable dividends or distributions with the common equity owners of the Company or Pioneer Southwest, as applicable. Participating share- or unit-based earnings represent the distributed and undistributed earnings of the Company attributable to the participating securities. Unvested restricted stock awards and phantom unit awards do not participate in undistributed net losses as they are not contractually obligated to do so.
	The following table is a reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013 (a)			2012
		(in millions)
	Weighted average common shares outstanding:
	Basic	144			136			123

	Convertible Senior Notes dilution (b)	—			—			3

	Diluted	144			136			126

	______________________

	(a)	The following common share equivalents were excluded from the weighted average diluted shares for the year ended December 31, 2013 because they would have been anti-dilutive to the loss recorded for the period: (i) 135,190 outstanding options to purchase the Company's common stock, (ii) 200,360 common shares attributable to unvested performance awards and (iii) 1,087,401 common shares related to the 2013 redemption of the Convertible Senior Notes, representing the weighted average portion of the year that is not included in the basic weighted average common shares outstanding.

	(b)	Weighted average common shares outstanding have been increased to reflect the dilutive effect that would have resulted if the Convertible Senior Notes had qualified for and been converted during the year ended December 31, 2012.

Summary_Of_Significant_Account1

Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Principles Of Consolidation

Principles of consolidation. The consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries since their acquisition or formation. All material intercompany balances and transactions have been eliminated.

Certain reclassifications have been made to the 2013 and 2012 financial statement and footnote amounts in order to conform them to the 2014 presentations.

Reclassification, Policy [Policy Text Block]

Certain reclassifications have been made to the 2013 and 2012 financial statement and footnote amounts in order to conform them to the 2014 presentations.

Use Of Estimates In The Preparation Of Financial Statements

Use of estimates in the preparation of financial statements. Preparation of the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Depletion of oil and gas properties and impairment of goodwill and proved and unproved oil and gas properties, in part, is determined using estimates of proved, probable and possible oil and gas reserves. There are numerous uncertainties inherent in the estimation of quantities of proved, probable and possible reserves and in the projection of future rates of production and the timing of development expenditures. Similarly, evaluations for impairment of proved and unproved oil and gas properties are subject to numerous uncertainties including, among others, estimates of future recoverable reserves and commodity price outlooks. Actual results could differ from the estimates and assumptions utilized.

Cash Equivalents

Cash and cash equivalents. The Company's cash and cash equivalents include depository accounts held by banks and marketable securities with original issuance maturities of 90 days or less.

Accounts Receivable

Accounts receivable. As of December 31, 2014 and 2013, the Company had accounts receivable – trade, net of allowances for bad debts, of $436 million and $431 million, respectively. The Company's accounts receivable – trade are primarily comprised of oil and gas sales receivables, joint interest receivables and other receivables for which the Company does not require collateral security.

As of both December 31, 2014 and 2013, the Company's allowances for doubtful accounts totaled $1 million. The Company establishes allowances for bad debts equal to the estimable portions of accounts receivable for which failure to collect is considered probable. The Company estimates the portions of joint interest receivables for which failure to collect is probable based on percentages of joint interest receivables that are past due. The Company estimates the portions of other receivables for which failure to collect is probable based on the relevant facts and circumstances surrounding the receivable. Allowances for doubtful accounts are recorded as reductions to the carrying values of the receivables included in the Company's consolidated balance sheets and as charges to other expense in the consolidated statements of operations in the accounting periods during which failure to collect an estimable portion is determined to be probable.

Inventories

Inventories. The Company's inventories consist of materials, supplies and commodities. The Company's materials and supplies inventory is primarily comprised of oil and gas drilling or repair items such as tubing, casing, proppant used to fracture-stimulate oil and gas wells, chemicals, operating supplies and ordinary maintenance materials and parts. The materials and supplies inventory is primarily acquired for use in future drilling operations or repair operations and is carried at the lower of cost or market, on a first-in, first-out cost basis. Valuation allowances for materials and supplies inventories are recorded as reductions to the carrying values of the materials and supplies inventories in the Company's consolidated balance sheets and as charges to other expense in the accompanying consolidated statements of operations.

Commodity inventories are carried at the lower of cost or market, on a first-in, first-out basis. The Company's commodity inventories consist of oil, natural gas liquids ("NGLs") and gas volumes held in storage or as linefill in pipelines. Any valuation allowances of commodity inventories are recorded as reductions to the carrying values of the commodity inventories included in the Company's consolidated balance sheets and as charges to other expense in the consolidated statements of operations.

The following table presents the Company's materials and supplies and commodity inventories as of December 31, 2014 and 2013:

As of December 31,

2014

2013

(in millions)

Materials and supplies (a)

223

211

Commodities

Less: Noncurrent materials and supplies (b)

—

)

241

220

____________________

(a)

As of December 31, 2014 and 2013, the Company's materials and supplies inventories were net of valuation allowances of $22 million and $32 million, respectively. See Note D for additional information regarding inventory impairments.

(b)

Included in other noncurrent assets in the Company's accompanying consolidated balance sheet.

Oil And Gas Properties

Oil and gas properties. The Company utilizes the successful efforts method of accounting for its oil and gas properties. Under this method, all costs associated with productive wells and nonproductive development wells are capitalized while nonproductive exploration costs and geological and geophysical expenditures are expensed. The Company capitalizes interest on expenditures for significant development projects, generally when the underlying project is sanctioned, until such projects are ready for their intended use.

The Company does not carry the costs of drilling an exploratory well as an asset in its consolidated balance sheets following the completion of drilling unless both of the following conditions are met:

(i)

The well has found a sufficient quantity of reserves to justify its completion as a producing well.

(ii)

The Company is making sufficient progress assessing the reserves and the economic and operating viability of the project.

Due to the capital intensive nature and the geographical location of certain projects, it may take an extended period of time to evaluate the future potential of an exploration project and the economics associated with making a determination on its commercial viability. In these instances, the project's feasibility is not contingent upon price improvements or advances in technology, but rather the Company's ongoing efforts and expenditures related to accurately predicting the hydrocarbon recoverability based on well information, gaining access to other companies' production data in the area, transportation or processing facilities and/or getting partner approval to drill additional appraisal wells. These activities are ongoing and are being pursued constantly. Consequently, the Company's assessment of suspended exploratory well costs is continuous until a decision can be made that the project has found sufficient proved reserves to sanction the project or is noncommercial and is charged to exploration and abandonments expense. See Note F for additional information regarding the Company's suspended exploratory well costs.

The Company owns interests in six gas processing plants and eight treating facilities. The Company is the operator of one of the gas processing plants and all eight of the treating facilities. The Company's ownership interests in the gas processing plants and treating facilities are primarily to accommodate handling the Company's gas production and thus are considered a component of the capital and operating costs of the respective fields that they service. To the extent that there is excess capacity at a plant or treating facility, the Company attempts to process third party gas volumes for a fee to keep the plant or treating facility at capacity. All revenues and expenses derived from third party gas volumes processed through the plants and treating facilities are reported as components of oil and gas production costs. Third party revenues generated from the processing plants and treating facilities in continuing operations for the years ended December 31, 2014, 2013 and 2012 were $56 million, $53 million and $31 million, respectively. Third party expenses attributable to the processing plants and treating facilities in continuing operations for the same respective periods were $24 million, $21 million and $19 million. The capitalized costs of the plants and treating facilities are included in proved oil and gas properties and are depleted using the unit-of-production method along with the other capitalized costs of the field that they service.

The capitalized costs of proved properties are depleted using the unit-of-production method based on proved reserves. Costs of significant nonproducing properties, wells in the process of being drilled and development projects are excluded from depletion until the related project is completed and proved reserves are established or, if unsuccessful, impairment is determined.

Proceeds from the sales of individual properties and the capitalized costs of individual properties sold or abandoned are credited and charged, respectively, to accumulated depletion, depreciation and amortization, if doing so does not materially impact the depletion rate of an amortization base. Generally, no gain or loss is recognized until an entire amortization base is sold. However, gain or loss is recognized from the sale of less than an entire amortization base if the disposition is significant enough to materially impact the depletion rate of the remaining properties in the amortization base.

The Company performs assessments of its long-lived assets to be held and used, including proved oil and gas properties accounted for under the successful efforts method of accounting, whenever events or circumstances indicate that the carrying value of those assets may not be recoverable. An impairment loss is indicated if the sum of the expected future cash flows is less than the carrying amount of the assets. In these circumstances, the Company recognizes an impairment loss for the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets. See Note D for additional information regarding the Company's impairment of proved oil and gas properties.

Unproved oil and gas properties are periodically assessed for impairment on a project-by-project basis. These impairment assessments are affected by the results of exploration activities, commodity price outlooks, planned future sales or expirations of all or a portion of such projects. If the estimated future net cash flows attributable to such projects are not expected to be sufficient to fully recover the costs invested in each project, the Company will recognize an impairment loss at that time.

Goodwill

Goodwill. During 2004, the Company recorded goodwill associated with a business combination, which represents the cost of an acquired entity over the net amounts assigned to assets acquired and liabilities assumed. In accordance with GAAP, goodwill is not amortized to earnings, but is assessed for impairment whenever events or circumstances indicate that impairment of the carrying value of goodwill is likely, but no less often than annually. If the carrying value of goodwill is determined to be impaired, it is reduced for the impaired value with a corresponding charge to earnings in the period in which it is determined to be impaired. During the third quarter of 2014, the Company performed its annual qualitative assessment of goodwill to determine whether it was more likely than not that the fair value of the Company's reporting unit was less than its carrying amount as a basis for determining whether it was necessary to perform the two-step goodwill impairment test. The Company reevaluated this assessment during the fourth quarter of 2014 due to reductions in (i) management's longer-term commodity price outlooks ("Management's Price Outlooks") and (ii) the Company's common stock price. Based upon the results of the assessments, the Company determined that it was not likely that the Company's goodwill was impaired.

The Company reduced the carrying value of goodwill by $2 million and $24 million during the years ended December 31, 2014 and 2013, respectively, reflecting the portion of the Company's goodwill related to assets sold or included in assets held for sale. During 2014, the reduction of goodwill primarily reflected the Company's goodwill related to the Hugoton field assets sold in September 2014, while the 2013 reduction was primarily associated with the sale of 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, and the planned sales of the Company's Alaska subsidiary and Barnett Shale net assets that were subsequently completed during 2014. See Note C for additional information regarding the Company's divestitures.

Other Property And Equipment, Net

Other property and equipment, net. Other property and equipment is recorded at cost. At December 31, 2014 and 2013, respectively, the net carrying value of other property and equipment consisted of the following:

As of December 31,

2014 (a)

2013 (a)

(in millions)

Proved and unproved sand properties (b)

469

451

Land and buildings

440

345

Equipment and rigs (c)

348

313

Transportation equipment

Furniture and fixtures

Leasehold improvements

1,391

1,224

____________________

(a)

At December 31, 2014 and 2013, other property and equipment was net of accumulated depreciation of $563 million and $458 million, respectively.

(b)

Includes sand mines, facilities and unproved leaseholds that primarily provide the Company and other unrelated customers with proppant used in the fracture stimulation of oil and gas wells.

(c)

Includes well servicing rigs and equipment and fracture stimulation equipment including assets owned by subsidiaries that provide pumping and well services on Company-operated properties. As of December 31, 2014, the Company owned eight fracture stimulation fleets and other oilfield services equipment, including pulling units, fracture stimulation tanks, water transport trucks, hot oilers, blowout preventers, construction equipment and fishing tools.

The primary purposes of the Company's sand mines and pumping and well services operations are to accommodate the Company's drilling and producing operations by increasing the availability of supplies, equipment and services, rather than being dependent on third-party availability, and to contain associated costs. All intercompany gains or losses of the Company's sand mines and pumping and well services operations are eliminated.

Earnings from sales of proppant to third-party customers and from providing pumping and well services to working interest owners in Company-operated properties are included in interest and other income in the accompanying consolidated statements of operations.

The capitalized costs of proved sand properties are depleted using the unit-of-production method based on proved sand reserves. Equipment items are generally depreciated by individual component on a straight line basis over their economic useful lives, which are generally from two to 12 years. Leasehold improvements are amortized over the lesser of their economic useful lives or the underlying terms of the associated leases.

The Company evaluates other property and equipment for potential impairment whenever indicators of impairment are present. Circumstances that could indicate potential impairment include: significant adverse changes in industry trends and the economic outlook; legal actions; regulatory changes; and significant declines in utilization rates or oil and gas prices. If it is determined that other property and equipment is potentially impaired, the Company performs an impairment evaluation by estimating the future undiscounted net cash flow from the use and eventual disposition of other property and equipment grouped at the lowest level that cash flows can be identified. If the sum of the future undiscounted net cash flows is less than the net book value of the property, an impairment loss is recognized for the excess, if any, of the assets' net book value over its estimated fair value.

Investment In Unconsolidated Affiliate

Investment in unconsolidated affiliate. During 2010, the Company formed EFS Midstream LLC ("EFS Midstream") to own and operate gas and liquids gathering, treating and transportation assets in the Eagle Ford Shale play in South Texas. During June 2010, the Company sold a 49.9 percent member interest in EFS Midstream to an unaffiliated third party for $46 million of cash proceeds. Associated therewith, the Company recorded a deferred gain that is being amortized as a reduction in production costs over a 20 year period, representing the term of a continuing commitment of Pioneer to deliver production volumes through EFS Midstream handling and gathering facilities. As of December 31, 2014, the deferred gain totaled $39 million and is included in other current and noncurrent liabilities in the Company's accompanying consolidated balance sheet.

The Company does not have control of EFS Midstream. Consequently, the Company accounts for this investment under the equity method of accounting for investments in unconsolidated affiliates. Under the equity method, the Company's investment in unconsolidated affiliates is increased for investments made and the investor's share of the investee's net income, and decreased for distributions received, the carrying value of member interests sold and the investor's share of the investee's net losses.

The Company's equity interest in the net income or loss of EFS Midstream is recorded in interest and other income, net of eliminations of the profit associated with gathering, treating and transportation fees charged to the Company by EFS Midstream, in the accompanying consolidated statements of operations. See Note M for the Company's equity interest in the net income of EFS Midstream for the years ended December 31, 2014, 2013 and 2012.

During November 2014, the Company announced that it is pursuing the divestment of its 50.1 percent share of EFS Midstream. The Company is marketing its equity investment in EFS Midstream and no assurance can be given that a sale will be completed in accordance with the Company's plans or on terms and at a price acceptable to the Company.

Asset Retirement Obligations

Asset retirement obligations. The Company records a liability for the fair value of an asset retirement obligation in the period in which it is incurred if a reasonable estimate of fair value can be made. Asset retirement obligations are generally capitalized as part of the carrying value of the long-lived asset to which it relates. Conditional asset retirement obligations meet the definition of liabilities and are recognized when incurred if their fair values can be reasonably estimated.

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 and expenditures are classified as cash used in operating activities in the accompanying consolidated statements of cash flows. See Note I for additional information about the Company's asset retirement obligations.

Treasury Stock

Treasury stock. Treasury stock purchases are recorded at cost. Upon reissuance, the cost of treasury shares held is reduced by the average purchase price per share of the aggregate treasury shares held.

Noncontrolling Interest In Consolidated Subsidiaries

Noncontrolling interest in consolidated subsidiaries. The Company owns the majority interests in certain subsidiaries with operations in the United States. Prior to December 17, 2013, the Company owned a 0.1 percent general partner interest and a 52.4 percent limited partner interest in Pioneer Southwest Energy Partners L.P. ("Pioneer Southwest") and consolidated the financial position, results of operations and cash flows of Pioneer Southwest with those of Pioneer. Pioneer Southwest owned proved and unproved oil and gas properties in the Spraberry field in the Permian Basin of West Texas. On December 17, 2013, the holders of a majority of the outstanding common units of Pioneer Southwest approved an amended agreement and plan of merger, pursuant to which (i) all of the then outstanding common units of Pioneer Southwest were canceled and converted into the right to receive 0.2325 of a share of common stock of the Company and (ii) Pioneer Southwest became a wholly-owned subsidiary of the Company. The changes in the Company's ownership of Pioneer Southwest were accounted for by eliminating the noncontrolling interest attributable to Pioneer Southwest. See Note C for additional information about Pioneer Southwest and the amended agreement and plan of merger.

Noncontrolling interests in the net assets of consolidated subsidiaries totaled $8 million and $13 million as of December 31, 2014 and 2013, respectively. For the year ended December 31, 2014, the Company recorded a nominal net loss attributable to the noncontrolling interests, as compared to $39 million and $51 million of net income attributable to the noncontrolling interests for the years ended December 31, 2013 and 2012, respectively. The decrease in income attributable to noncontrolling interests for the year ended December 31, 2014, as compared to 2013 and 2012, is due to the Company's acquisition of all of the outstanding common units of Pioneer Southwest not owned by the Company in December 2013.

In accordance with GAAP, the Company records transfers of any gains or losses, net of taxes, from noncontrolling interests in consolidated subsidiaries to additional paid in capital proportionate to the ownership after giving effect to the purchase or sale of common units. The following table presents the Company's net income or loss attributable to common stockholders adjusted for changes in equity as a result of transactions that changed the Company's ownership interest in Pioneer Southwest:

Year Ended December 31,

2014

2013

2012

(in millions)

Net income (loss) attributable to common stockholders

930

(838

)

192

Transfers from the noncontrolling interest in consolidated subsidiaries:

Decrease in additional paid-in capital for deferred taxes recognized attributable to Pioneer Southwest's 2008 initial public offering of 9.5 million common units

—

(49

)

Increase in additional paid-in capital from Pioneer Southwest merger

—

169

—

Increase in additional paid-in capital from deferred taxes recognized attributable to Pioneer Southwest merger

—

200

—

Decrease in additional paid-in capital from Pioneer Southwest merger transaction costs

)

—

Net increase (decrease) in equity from transactions with noncontrolling interests

)

365

(49

)

Net income (loss) attributable to common stockholders and changes in equity from transactions with noncontrolling interests

929

(473

)

143

Revenue Recognition

Revenue recognition. The Company recognizes revenue when it is realized or realizable and earned. Revenues are considered realized or realizable and earned when: (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the seller's price to the buyer is fixed or determinable and (iv) collectability is reasonably assured.

The Company uses the entitlements method of accounting for oil, NGLs and gas revenues. Sales proceeds in excess of the Company's entitlement are included in other liabilities and the Company's share of sales taken by others is included in other assets in the accompanying consolidated balance sheets. The Company had no material oil, NGL or gas entitlement assets or liabilities as of December 31, 2014 or 2013.

The Company enters into purchase transactions with third parties and separate sale transactions with third parties to satisfy unused pipeline capacity commitments and to diversify a portion of the Company's WTI oil sales to a Gulf Coast market price. Revenues and expenses from these transactions are presented on a gross basis as the Company acts as a principal in the transaction by assuming the risk and rewards of ownership, including credit risk, of the commodities purchased and assuming responsibility to deliver the commodities sold. Deficiency payments on excess pipeline capacity are included in other expense in the accompanying consolidated statements of operations. See Note N for further information on transportation commitment charges.

Derivatives And Hedging

Derivatives. All derivatives are recorded in the accompanying consolidated balance sheets at estimated fair value. Effective February 1, 2009, the Company discontinued hedge accounting on all of its then-existing hedge contracts. The effective portions of the discontinued deferred hedges as of February 1, 2009 were included in accumulated other comprehensive income (loss) ("AOCI - Hedging") and were transferred to earnings during the same periods in which the forecasted hedged transactions were recognized in the Company's earnings. During 2012, the remaining AOCI - Hedging losses were transferred to earnings. Since discontinuing hedge accounting, the Company has recognized all changes in the fair values of its derivative contracts 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 executed under master netting arrangements as net current or noncurrent derivative assets or net current or noncurrent derivative liabilities, whichever the case may be, by commodity and counterparty. Net derivative asset values are determined, in part, by utilization of the derivative counterparties' credit-adjusted risk-free rate curves and net derivative liabilities are determined, in part, by utilization of the Company's credit-adjusted risk-free rate curve. The credit-adjusted risk-free rate curves for the Company and the counterparties are based on their independent market-quoted credit default swap rate curves plus the United States Treasury Bill yield curve as of the valuation date. See Note E for additional information about the Company's derivative instruments.

Environmental

Environmental. The Company's environmental expenditures are expensed or capitalized depending on their future economic benefit. Expenditures that relate to an existing condition caused by past operations and that have no future economic benefits are expensed. Expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities for expenditures that will not qualify for capitalization are recorded when environmental assessment and/or remediation is probable and the costs can be reasonably estimated. Such liabilities are undiscounted unless the timing of cash payments for the liability is fixed or reliably determinable. Environmental liabilities normally involve estimates that are subject to revision until settlement occurs.

Stock-Based Compensation

Stock-based compensation. Stock-based compensation expense is being recognized on restricted stock, restricted stock units, performance units and stock option awards that are expected to be settled in the Company's common stock ("Equity Awards") in the Company's financial statements on a straight line basis over the awards' vesting periods based on their fair values on the dates of grant or modification, as applicable. Stock-based compensation awards generally vest over a period of three years. The amount of stock-based compensation expense recognized at any date is approximately equal to the ratable portion of the grant date value of the award that is vested at that date.

Stock-based compensation liability awards ("Liability Awards") are restricted stock awards that are expected to be settled in cash on their vesting dates, rather than in common stock. Liability Awards are recorded as accounts payable—affiliates based on the vested portion of the fair value of the awards on the balance sheet date. The fair values of Liability Awards are updated at each balance sheet date and changes in the fair values of the vested portions of the awards are recorded as increases or decreases to stock-based compensation expense.

The Company utilizes (i) the Black-Scholes option pricing model to measure the fair value of stock options, (ii) the prior day's closing stock price on the date of grant for the fair value of Equity Awards and Liability Awards and (iii) the Monte Carlo simulation method for the fair value of performance unit awards.

Segment Reporting

Segments. Operating segments are defined as components of an enterprise that (i) engage in activities from which it may earn revenues and incur expenses (ii) for which separate operational financial information is available and is regularly evaluated by the chief operating decision maker for the purpose of allocating resources and assessing performance.

Based upon how the Company is organized and managed, the Company has only one reportable operating segment, which is oil and gas exploration and production. The Company considers its vertical integration services as ancillary to its oil and gas exploration and producing activities and manages these services to support such activities. In addition, the Company has a single, company-wide management team that allocates capital resources to maximize profitability and measures financial performance as a single enterprise.

Assets Held for Sale and Discontinued Operations

Assets held for sale and discontinued operations. On the date at which the Company meets all the held for sale criteria, the Company discontinues the recording of depletion and depreciation of the assets or asset group to be sold and reclassifies the assets and related liabilities to be sold as held for sale on the accompanying consolidated balance sheets. The assets and liabilities are measured at the lower of their carrying amount or estimated fair value less cost to sell.

In addition, after determining that held for sale criteria has been met, the Company considers whether the assets held for sale meet the criteria to be considered discontinued operations. If the assets held for sale are considered discontinued operations, the Company classifies the results of operations from the assets held for sale as income or loss from discontinued operations, net of tax in the accompanying consolidated statements of operations for the current period and all prior periods. See Note C for additional information about the Company's divestitures.

New Accounting Pronouncements

New accounting pronouncements. In February 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 is effective for periods beginning after December 15, 2015 with early adoption permitted. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements.

In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)," which supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") Topic 605, "Revenue Recognition," and most industry-specific guidance. ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB ASC. The new guidance is effective for annual reporting periods beginning after December 15, 2016 for public companies. Early adoption is not permitted. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements or decided upon the method of adoption.

In April 2014, the FASB issued ASU 2014-08, "Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity." ASU 2014-08 prospectively changes the criteria for reporting discontinued operations while enhancing disclosures around disposals of assets whether or not the disposal meets the definition of a discontinued operation. ASU 2014-08 is effective for annual and interim periods beginning after December 31, 2014 with early adoption permitted but only for disposals that have not been reported in financial statements previously issued. The impact of this guidance on the Company's consolidated financial statements will depend on the size and nature of the Company's disposal transactions in the future, which the Company cannot accurately predict. Several of the Company's past dispositions that were treated as discontinued operations may not have been classified as such had the new guidance been in effect.

Net_IncomePer_Share_Attributab

Net IncomePer Share Attributable To Common Stockholders Net Income Per Share Attributable to Common Stockholders (Policies)	12 Months Ended
	Dec. 31, 2014
Net Income Per Share Attributable to Common Stockholders [Abstract]
Earnings Per Share, Policy [Policy Text Block]	In the calculation of basic net income (loss) per share attributable to common stockholders, participating securities are allocated earnings based on actual dividend distributions received plus a proportionate share of undistributed net income attributable to common stockholders, if any, after recognizing distributed earnings. The Company's participating securities do not participate in undistributed net losses because they are not contractually obligated to do so. The computation of diluted net income (loss) per share attributable to common stockholders reflects the potential dilution that could occur if securities or other contracts to issue common stock that are dilutive were exercised or converted into common stock or resulted in the issuance of common stock that would then share in the earnings of the Company. 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 not be dilutive to net loss per share and conversion into common stock is assumed not to occur. Diluted net income (loss) per share is calculated under both the two-class method and the treasury stock method and the more dilutive of the two calculations is presented.
Earnings Per Share, Policy [Policy Text Block]	The Company's basic net income (loss) per share attributable to common stockholders is computed as (i) net income (loss) attributable to common stockholders, (ii) less participating share- and unit-based basic earnings (iii) divided by weighted average basic shares outstanding. The Company's diluted net income (loss) per share attributable to common stockholders is computed as (i) basic net income (loss) attributable to common stockholders, (ii) plus diluted adjustments to participating undistributed earnings (iii) divided by weighted average diluted shares outstanding.

Summary_Of_Significant_Account2

Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Inventory, Current [Table Text Block]	The following table presents the Company's materials and supplies and commodity inventories as of December 31, 2014 and 2013:


			As of December 31,
			2014			2013
			(in millions)
	Materials and supplies (a)		$	223		$	211

	Commodities		18			13

	Less: Noncurrent materials and supplies (b)		—			(4		)

			$	241		$	220

	____________________

	(a)	As of December 31, 2014 and 2013, the Company's materials and supplies inventories were net of valuation allowances of $22 million and $32 million, respectively. See Note D for additional information regarding inventory impairments.

	(b)	Included in other noncurrent assets in the Company's accompanying consolidated balance sheet.
Other Property Plant and Equipment [Table Text Block]	At December 31, 2014 and 2013, respectively, the net carrying value of other property and equipment consisted of the following:


			As of December 31,
			2014 (a)			2013 (a)
			(in millions)
	Proved and unproved sand properties (b)		$	469		$	451

	Land and buildings		440			345

	Equipment and rigs (c)		348			313

	Transportation equipment		35			41

	Furniture and fixtures		70			48

	Leasehold improvements		29			26

			$	1,391		$	1,224

	____________________

	(a)	At December 31, 2014 and 2013, other property and equipment was net of accumulated depreciation of $563 million and $458 million, respectively.

	(b)	Includes sand mines, facilities and unproved leaseholds that primarily provide the Company and other unrelated customers with proppant used in the fracture stimulation of oil and gas wells.

	(c)	Includes well servicing rigs and equipment and fracture stimulation equipment including assets owned by subsidiaries that provide pumping and well services on Company-operated properties. As of December 31, 2014, the Company owned eight fracture stimulation fleets and other oilfield services equipment, including pulling units, fracture stimulation tanks, water transport trucks, hot oilers, blowout preventers, construction equipment and fishing tools.
Schedule of Other Ownership Interests [Table Text Block]	The following table presents the Company's net income or loss attributable to common stockholders adjusted for changes in equity as a result of transactions that changed the Company's ownership interest in Pioneer Southwest:



		Year Ended December 31,
		2014			2013				2012
		(in millions)
	Net income (loss) attributable to common stockholders	$	930		$	(838	)		$	192

	Transfers from the noncontrolling interest in consolidated subsidiaries:
	Decrease in additional paid-in capital for deferred taxes recognized attributable to Pioneer Southwest's 2008 initial public offering of 9.5 million common units	—			—				(49		)

	Increase in additional paid-in capital from Pioneer Southwest merger	—			169				—

	Increase in additional paid-in capital from deferred taxes recognized attributable to Pioneer Southwest merger	—			200				—

	Decrease in additional paid-in capital from Pioneer Southwest merger transaction costs	(1		)	(4		)		—

	Net increase (decrease) in equity from transactions with noncontrolling interests	(1		)	365				(49		)

	Net income (loss) attributable to common stockholders and changes in equity from transactions with noncontrolling interests	$	929		$	(473	)		$	143

Acquisitions_and_Divestitures_

Acquisitions and Divestitures Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2014
Acquisitions and Divestitures [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	The following table represents the components of the Company's discontinued operations for the years ended December 31, 2014, 2013 and 2012:


			Year Ended December 31,
			2014			2013			2012
			(in millions)
	Revenues and other income:
	Oil and gas		$	198		$	329		$	349

	Interest and other (a)		31			38			29

	Gain on disposition of assets, net		9			9			41

			238			376			419

	Costs and expenses:
	Oil and gas production		60			117			107

	Production and ad valorem taxes		12			19			19

	Depletion, depreciation and amortization		11			122			121

	Impairment of oil and gas properties (b)		305			729			533

	Exploration and abandonments		4			54			109

	General and administrative		3			12			6

	Accretion of discount on asset retirement obligations		1			1			3

	Other		13			9			3

			409			1,063			901

	Loss from discontinued operations before income taxes		(171		)	(687		)	(482		)
	Current tax provision		—			(6		)	(10		)

	Deferred tax benefit		60			255			191

	Loss from discontinued operations		$	(111	)	$	(438	)	$	(301	)
	____________________

	(a)	Primarily comprised of Alaskan Petroleum Production Tax credits on qualifying capital expenditures.

	(b)	Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Table Text Block]	As of December 31, 2013, the carrying values of the Company's ownership in Pioneer Alaska, the Barnett Shale field and Sendero were included in assets and liabilities held for sale in the accompanying consolidated balance sheet and were comprised of the following (the Company had no assets held for sale as of December 31, 2014):


			31-Dec-13
			(in millions)
	Composition of assets included in assets held for sale:
	Current assets (excluding cash and cash equivalents)		$	58

	Property, plant and equipment		526

	Total assets		$	584


	Composition of liabilities included in liabilities held for sale:
	Current liabilities		$	29

	Other liabilities		10

	Total liabilities		$	39

Disclosures_About_Fair_Value_M1

Disclosures About Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets And Liabilities That Are Measured At Fair Value On A Recurring Basis	The following tables present the Company's assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2014 and 2013 for each of the fair value hierarchy levels:



		Fair Value Measurements at December 31, 2014 Using
		Quoted Prices in				Significant Other				Significant				Fair Value at December 31, 2014
		Active Markets for				Observable				Unobservable
		Identical Assets				Inputs				Inputs
		(Level 1)				(Level 2)				(Level 3)
		(in millions)
	Assets:
	Commodity derivatives	$	—			$	759			$	—			$	759

	Deferred compensation plan assets	70				—				—				70

	Total assets	70				759				—				829

	Liabilities:
	Commodity derivatives	—				2				—				2

	Interest rate derivatives	—				3				—				3

	Total liabilities	—				5				—				5

	Total recurring fair value measurements	$	70			$	754			$	—			$	824




		Fair Value Measurements at December 31, 2013 Using
		Quoted Prices in				Significant Other				Significant				Fair Value at December 31, 2013
		Active Markets for				Observable				Unobservable
		Identical Assets				Inputs				Inputs
		(Level 1)				(Level 2)				(Level 3)
		(in millions)
	Assets:
	Commodity derivatives	$	—			$	157			$	—			$	157

	Interest rate derivatives	—				10				—				10

	Deferred compensation plan assets	64				—				—				64

	Total assets	64				167				—				231

	Liabilities:
	Commodity derivatives	—				12				—				12

	Interest rate derivatives	—				10				—				10

	Total liabilities	—				22				—				22

	Total recurring fair value measurements	$	64			$	145			$	—			$	209

Fair Value Measurements, Nonrecurring [Table Text Block]	The following table presents the fair value and fair value adjustments (in millions) for the Company's 2013 and 2012 proved property impairments, as well as the average oil price per barrel ("Bbl") and gas price per British thermal unit ("MMBtu") utilized in respective Management's Price Outlooks:


			Year ended		Fair				Fair Value				Management's Price Outlooks
			December 31,		Value				Adjustment				Oil				Gas

	Barnett Shale		2012		$	185			$	(533	)		$	87.09			$	4.78

	Raton		2013		$	534			$	(1,495	)		$	80.4			$	4.43

Fair Value of Assets Classified as Held for Sale [Table Text Block]	The following table presents the fair value adjustments made by the Company during the years ended December 31, 2014 and 2013 related to assets associated with divestitures:


					Year Ended December 31, 2014								Year Ended December 31, 2013
			Classification		Estimated Fair Value Less Costs to Sell				Fair Value Adjustment				Estimated Fair Value Less Costs to Sell				Fair Value Adjustment
					(in millions)
	Sendero		Continuing operations										$	31			$	(25	)

	Pioneer Alaska		Discontinued operations		$	253			$	(97	)		$	351			$	(539	)

	Barnett Shale field		Discontinued operations		$	149			$	(174	)		$	180			$	(190	)

	Hugoton field		Discontinued operations		$	328			$	(34	)

Fair Value Measurements Not Carried At Fair Value	Carrying values and fair values of financial instruments that are not carried at fair value in the consolidated balance sheet as of December 31, 2014 and 2013 are as follows:



			31-Dec-14								31-Dec-13
			Carrying				Fair				Carrying				Fair
			Value				Value				Value				Value
			(in millions)
	Long-term debt		$	2,665			$	2,938			$	2,653			$	3,019

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Oil Derivative Contracts Volume And Weighted Average Price	The following table sets forth the volumes per day associated with the Company's outstanding oil derivative contracts as of December 31, 2014 and the weighted average oil prices for those contracts:



		2015				2016
	Swap contracts:
	Volume (Bbls)	82,000				—

	Price per Bbl	$	71.18			$	—

	Collar contracts with short puts:
	Volume (Bbls) (a)(b)	13,767				73,000

	Price per Bbl:
	Ceiling	$	101.36			$	96.46

	Floor	$	86.82			$	85.47

	Short put	$	75.73			$	74.35

	Rollfactor swap contracts:
	Volume (Bbl)	36,575				—

	NYMEX roll price (c)	$	0.06			$	—

	____________________

	(a)	Counterparties have the option to extend for an additional year 5,000 Bbls per day of 2015 collar contracts with short puts with a ceiling price of $100.08 per Bbl, a floor price of $90.00 per Bbl and a short put price of $80.00 per Bbl. The option to extend is exercisable on December 31, 2015. These contracts give the counterparties the option to extend the contracts under the same terms for an additional year if the option to extend is exercised by the counterparties on December 31, 2015.
	(b) During the period from January 1, 2015 through February 13, 2015, the Company converted (i) 3,000 Bbls per day of 2015 collar contracts with short puts into new 2015 collar contract with short puts with a ceiling price of $78.33 per Bbl, a floor price of $66.50 per Bbl and a short put price of $40.00 per Bbl and (ii) 55,000 Bbls per day of 2016 collar contracts with short puts into new 2016 collar contracts with short puts with a ceiling price of $77.41 per Bbl, a floor price of $66.58 per Bbl and a short put price of $41.55 per Bbl.

	(c)	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.
Schedule of NGL Derivative Volumes and Weighted Average Prices [Table Text Block]	The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of December 31, 2014 and the weighted average NGL prices for those contracts:


		2015				2016
	Swap contracts:
	Volume (Bbl) (a)	—				4,000

	Average price per Bbl:	$	—			$	12.29

	____________________

	(a)	Represent derivative contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.
Gas Volume And Weighted Average Price	The following table sets forth the volumes per day associated with the Company's outstanding gas derivative contracts as of December 31, 2014 and the weighted average gas prices for those contracts:



		2015				2016				2017
	Swap contracts:
	Volume (MMBtu)	20,000				70,000				—

	Price per MMBtu	$	4.31			$	4.06			$	—

	Collar contracts with short puts:
	Volume (MMBtu)	285,000				20,000				—

	Price per MMBtu:
	Ceiling	$	5.07			$	5.36			$	—

	Floor	$	4			$	4			$	—

	Short put	$	3			$	3			$	—

	Basis swap contracts:
	Gulf Coast basis swap contracts (a)	20,000				—				—

	Price differential ($/MMBtu)	$	—			$	—			$	—

	Mid-Continent index swap volume (a)	95,000				15,000				30,000

	Price differential ($/MMBtu)	$	(0.24	)		$	(0.32	)		$	(0.34	)
	Permian Basin index swap volume (a)	10,000				—				—

	Price differential ($/MMBtu)	$	(0.13	)		$	—			$	—

	____________________

	(a)	Represent swaps that fix the basis differentials between the index prices at which the Company sells its Gulf Coast, Mid-Continent and Permian Basin gas, respectively, and the NYMEX Henry Hub index price used in gas swap and collar contracts.
Offsetting Asset and Liability [Table Text Block]	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 December 31, 2014
	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 millions)
	Derivatives not designated as hedging instruments
	Asset Derivatives:
	Commodity price derivatives		Derivatives - current		$	579			$	(1	)		$	578

	Commodity price derivatives		Derivatives - noncurrent		$	182			$	(1	)		181

													$	759

	Liability Derivatives:
	Commodity price derivatives		Derivatives - current		$	1			$	(1	)		$	—

	Interest rate derivatives		Derivatives - current		3				$	—			3

	Commodity price derivatives		Derivatives - noncurrent		$	3			$	(1	)		2

													$	5




	Fair Value of Derivative Instruments as of December 31, 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 millions)
	Derivatives not designated as hedging instruments
	Asset Derivatives:
	Commodity price derivatives		Derivatives - current		$	73			$	(7	)		$	66

	Interest rate derivatives		Derivatives - current		$	10			$	—			10

	Commodity price derivatives		Derivatives - noncurrent		$	95			$	(4	)		91

	Interest rate derivatives		Derivatives - noncurrent		$	15			$	(15	)		—

													$	167

	Liability Derivatives:
	Commodity price derivatives		Derivatives - current		$	19			$	(7	)		$	12

	Commodity price derivatives		Derivatives - noncurrent		$	4			$	(4	)		—

	Interest rate derivatives		Derivatives - noncurrent		$	25			$	(15	)		10

													$	22

Schedule of Derivative Obligations Under Terminated Hedge Arrangements [Table Text Block]	The following table details the location of gains and losses reclassified from AOCI-Hedging into earnings on the Company's discontinued cash flow hedging contracts in the accompanying consolidated statements of operations:


	Derivatives in Cash Flow Hedging Relationships		Location of Gain/(Loss)		Amount of Gain/(Loss) Reclassified
			Reclassified from AOCI		from AOCI into Earnings
			into Earnings		Year Ended December 31,
					2014				2013				2012
					(in millions)
	Commodity price derivatives		Oil and gas revenue		$	—			$	—			$	(3	)

	Interest rate derivatives		Interest expense		—				—				(2		)

	Total				$	—			$	—			$	(5	)

Schedule of Derivative Gains and Losses Recognized on Statement of Operations [Table Text Block]	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 Instruments		Location of Gain/(Loss)		Amount of Gain/(Loss) Recognized in
			Recognized in Earnings on Derivatives		Earnings on Derivatives
					Year Ended December 31,
					2014				2013				2012
					(in millions)
	Commodity price derivatives		Derivative gains, net		$	697			$	(6	)		$	353

	Interest rate derivatives		Derivative gains, net		15				10				(23		)

	Total				$	712			$	4			$	330

Schedule of Derivative Assets and Liabilities by Counterparty [Table Text Block]	The following table provides the Company's net derivative assets or liabilities by counterparty as of December 31, 2014:



		Net Assets
		(in millions)
	JP Morgan Chase	$	130

	J. Aron & Company	120

	Merrill Lynch	101

	Citibank, N.A.	98

	Morgan Stanley	69

	BMO Financial Group	47

	Barclays Capital	45

	Wells Fargo Bank, N.A.	44

	Societe Generale	39

	Macquarie Bank	19

	Credit Suisse	18

	Toronto Dominion	12

	Den Norske Bank	11

	Royal Bank of Canada	1

	Total	$	754

Exploratory_Well_Costs_Tables

Exploratory Well Costs (Tables)	12 Months Ended
	Dec. 31, 2014
Capitalized Exploratory Well Costs [Abstract]
Capitalized Exploratory Well And Project Activity	The following table reflects the Company's capitalized exploratory well and project activity during each of the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Beginning capitalized exploratory well costs	$	159		$	213		$	108

	Additions to exploratory well costs pending the determination of proved reserves	1,860			1,220			926

	Reclassification due to determination of proved reserves	(1,628		)	(1,045		)	(790		)
	Disposition of assets sold	(47		)	(93		)	—

	Impairment of properties	(13		)	(87		)	—

	Exploratory well costs charged to exploration and abandonment expense (a)	(26		)	(49		)	(31		)
	Ending capitalized exploratory well costs (b)	$	305		$	159		$	213

	_______________

	(a)	Includes exploration and abandonment expense of $43 million and $22 million in 2013 and 2012, respectively, that is included in discontinued operations for each respective period in the accompanying consolidated statements of operations.

	(b)	The December 31, 2013 balance includes $60 million of capitalized exploratory well costs classified as held for sale in the accompanying consolidated balance sheet as of December 31, 2013.
Capitalized Exploratory Costs And The Number Of Projects For Which Exploratory Costs Have Been Capitalized	The following table provides an aging, as of December 31, 2014, 2013 and 2012 of capitalized exploratory costs and the number of projects for which exploratory well costs have been capitalized for a period greater than one year, based on the date drilling was completed:



		As of December 31,
		2014			2013			2012
		(in millions, except well counts)
	Capitalized exploratory well costs that have been suspended:
	One year or less	$	305		$	116		$	191

	More than one year	—			43			22

		$	305		$	159		$	213

	Number of projects with exploratory well costs that have been suspended for a period greater than one year	—			1			1

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Components Of Long-Term Debt	Long-term debt, including the effects of issuance discounts and net deferred fair value hedge losses, consisted of the following components at December 31, 2014 and 2013:



		December 31,
		2014			2013
		(in millions)
	Outstanding debt principal balances:
	5.875% senior notes due 2016	$	455		$	455

	6.65% senior notes due 2017	485			485

	6.875 % senior notes due 2018	450			450

	7.500 % senior notes due 2020	450			450

	3.95% senior notes due 2022	600			600

	7.20% senior notes due 2028	250			250

		2,690			2,690

	Issuance discounts	(24		)	(36		)
	Net deferred fair value hedge losses	(1		)	(1		)
	Total long-term debt	$	2,665		$	2,653

Principal Maturities Of Long-Term Debt	Principal maturities of long-term debt at December 31, 2014, are as follows (in millions):



	2015	$	—

	2016	$	455

	2017	$	485

	2018	$	450

	2019	$	—

	Thereafter	$	1,300

Interest Expense	The following amounts have been incurred and charged to interest expense for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Cash payments for interest	$	193		$	183		$	168

	Amortization of issuance discounts	12			12			28

	Amortization of net deferred hedge losses (a)	—			—			2

	Amortization of capitalized loan fees	5			5			6

	Net changes in accruals	(22		)	(6		)	11

	Interest incurred	188			194			215

	Less capitalized interest	(4		)	(10		)	(11		)
	Total interest expense	$	184		$	184		$	204

	_______________

	(a)	Includes interest rate derivative hedges of $2 million for the period ended December 31, 2012 that were reclassified from AOCI - Hedging into earnings upon expiration (see Note E).

Incentive_Plans_Tables

Incentive Plans (Tables)	12 Months Ended
Incentive Plans (Tables)	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Number Of Shares Available Under The Company's Long Term Incentive Plan	The following table shows the number of shares available for issuance pursuant to awards under the Company's LTIP at December 31, 2014:



	Approved and authorized awards	9,100,000
	Approved and authorized awards	9,100,000
	Awards issued after May 3, 2006	(6,738,082	)
	Awards available for future grant	2,361,918
	Awards available for future grant	2,361,918
Number Of Awards Available Under PSE Long Term Incentive Plan	The following table shows the number of Pioneer common shares available for issuance pursuant to awards under the PSE LTIP at December 31, 2014:



	Approved and authorized awards	678,034
	Approved and authorized awards	678,034
	Awards issued under the PSE LTIP	(23,192	)
	Awards available for future grant	654,842
	Awards available for future grant	654,842
Schedule Of Employee Stock Purchase Plan	The following table shows the number of shares available for issuance under the ESPP at December 31, 2014:



	Approved and authorized shares	1,250,000
	Approved and authorized shares	1,250,000
	Shares issued	(774,638	)
	Shares available for future issuance	475,362
	Shares available for future issuance	475,362
Schedule Of Compensation Expense For Each Type Of Incentive Award	The following table reflects stock-based compensation expense recorded for each type of stock-based compensation award and the associated income tax benefit for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013				2012
		(in millions)
	Restricted stock-Equity Awards	$	65			$	57			$	50
	Restricted stock-Equity Awards	$	65			$	57			$	50
	Restricted stock-Liability Awards	28				40				23
	Restricted stock-Liability Awards	28				40				23
	Stock options (a)	2				3				4
	Stock options (a)	2				3				4
	Performance unit awards	13				9				6
	Performance unit awards	13				9				6
	ESPP	2				2				2
	ESPP	2				2				2
	Other	—				1				1
	Other	—				1				1
	Total	$	110			$	112			$	86
	Total	$	110			$	112			$	86
	Income tax benefit	$	33			$	36			$	28
	Income tax benefit	$	33			$	36			$	28
	_____________________

	(a)	Cash proceeds received from stock option exercises during 2014, 2013 and 2012 amounted to $6 million, $5 million and $3 million, respectively.
Schedule Of Restricted Stock Award Activity	The following table reflects the restricted stock award activity for the year ended December 31, 2014:



		Equity Awards							Liability Awards
		Number of			Weighted				Number of Shares
		Shares			Average Grant-
					Date Fair
					Value
	Outstanding at beginning of year	1,371,207			$	117.09			422,382
	Outstanding at beginning of year	1,371,207			$	117.09			422,382
	Shares granted	406,617			$	184.39			140,093
	Shares granted	406,617			$	184.39			140,093
	Shares forfeited	(79,777	)		$	134.25			(33,052	)
	Shares forfeited	(79,777	)		$	134.25			(33,052	)
	Shares vested	(464,508	)		$	108.79			(201,336	)
	Shares vested	(464,508	)		$	108.79			(201,336	)
	Outstanding at end of year	1,233,539			$	140.57			328,087
	Outstanding at end of year	1,233,539			$	140.57			328,087
Schedule Of Weighted-Average Assumptions To Estimate The Fair Value	The Company used the following weighted-average assumptions to estimate the fair value of stock options granted during the year ended December 31, 2012:



		2012
	Expected option life - years	7
	Expected option life - years	7
	Volatility	49.4	%
	Risk-free interest rate	1.5	%
	Dividend yield	0.4	%
Schedule Of Stock Options Awards Activity	A summary of the Company's nonstatutory stock option awards activity for the year ended December 31, 2014 is presented below:



		Number			Weighted				Weighted		Aggregate
		of Shares			Average				Average		Intrinsic Value
					Exercise Price				Remaining
									Contractual
									Life
									(in years)		(in millions)
	Outstanding at beginning of year	289,927			$	74.9
	Outstanding at beginning of year	289,927			$	74.9
	Options exercised	(90,869	)		$	69.19
	Options exercised	(90,869	)		$	69.19
	Outstanding at end of year	199,058			$	77.51			5.96		$	14
	Outstanding at end of year	199,058			$	77.51			5.96		$	14
	Exercisable at end of year	106,278			$	45.86			4.92		$	11
	Exercisable at end of year	106,278			$	45.86			4.92		$	11
Schedule of Assumptions Used [Table Text Block]	The Company used the following assumptions to estimate the fair value of performance unit awards granted during 2014, 2013 and 2012:



		2014					2013					2012
	Risk-free interest rate	0.62%					0.40%					0.40%
	Range of volatilities	29	%	-	41.50%		30.4	%	-	42.90%		33.6	%	-	49.00%
Schedule Of Performance Unit Activity	The following table summarizes the performance unit activity for the year ended December 31, 2014:



		Number of			Weighted Average
		Units (a)			Grant-Date
					Fair Value
	Beginning performance unit awards	134,476			$	183.66
	Beginning performance unit awards	134,476			$	183.66
	Units granted	67,182			$	232.2
	Units granted	67,182			$	232.2
	Units forfeited	(1,153	)		$	189.23
	Units forfeited	(1,153	)		$	189.23
	Units vested (b)	(45,772	)		$	172.87
	Units vested (b)	(45,772	)		$	172.87
	Ending performance unit awards	154,733			$	207.88
	Ending performance unit awards	154,733			$	207.88
	_____________________

	(a)	These amounts reflect the number of performance units granted. The actual payout of shares may be between zero percent and 250 percent of the performance units granted depending upon the total shareholder return ranking of the Company compared to peer companies at the vesting date.

	(b)	On December 31, 2014, the service period lapsed on 44,949 of these performance unit awards, which does not include 823 retirement deferred shares scheduled for release on December 31, 2015. The lapsed units earned two shares for each vested award representing 89,898 aggregate shares of common stock issued on January 2, 2015.

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation [Abstract]
Schedule Of Asset Retirement Obligations	The following table summarizes the Company's asset retirement obligation activity during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Beginning asset retirement obligations	$	194		$	198		$	137

	Obligations assumed in acquisitions	6			—			10

	New wells placed on production	5			6			10

	Changes in estimates (a)	7			8			52

	Disposition of wells	(14		)	(16		)	(2		)
	Obligations settled	(21		)	(15		)	(18		)
	Accretion of discount on continuing operations	12			12			8

	Accretion of discount on discontinued operations	—			1			1

	Ending asset retirement obligations	$	189		$	194		$	198

	_____________________

	(a)	The changes in the 2014, 2013 and 2012 estimates are primarily due to increases in abandonment cost estimates based on recent actual costs incurred to abandon wells and declines in the credit-adjusted risk-free discount rates used to value the Company's asset retirement obligations. The increases in the 2014 and 2012 estimates were further impacted by declines in oil, NGL and gas prices used to calculate proved reserves, which had the effect of shortening the economic life of certain wells and increasing the present value of future retirement obligations. The increases in 2013 estimates were partially offset by higher commodity prices, which had the effect of lengthening the economic life of certain wells and decreasing the present value of future retirement obligations.

Commitments_And_Contingencies_

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Drilling Commitments [Table Text Block]	Future minimum drilling commitments at December 31, 2014 are as follows (in millions):


	2015	$	303

	2016	$	197

	2017	$	113

	2018	$	32

	2019	$	2

	Thereafter	$	—

Future Minimum Lease Commitments	Future minimum lease commitments under noncancelable operating leases at December 31, 2014 are as follows (in millions):



	2015	$	30

	2016	$	22

	2017	$	20

	2018	$	19

	2019	$	19

	Thereafter	$	27

Future Minimum Gathering, Processing And Transportation Fees	Future minimum purchase, gathering, processing, transportation and fractionation commitments at December 31, 2014 are as follows (in millions):



	2015	$	455

	2016	$	486

	2017	$	364

	2018	$	332

	2019	$	325

	Thereafter	$	1,011

Major_Customers_Tables

Major Customers (Tables)	12 Months Ended
Major Customers (Tables)	Dec. 31, 2014
Major Customers And Derivative Counterparties [Abstract]
Consolidated Oil, NGL And Gas Revenues	The following purchasers individually accounted for ten percent or more of the Company's consolidated oil, NGL and gas revenues, including the revenues from discontinued operations, in at least one of the three years ended December 31, 2014:



		Year Ended December 31,
		2014		2013		2012
	Plains Marketing LP	24	%	26	%	25	%
	Occidental Energy Marketing Inc.	13	%	12	%	13	%
	Enterprise Products Partners L.P.	11	%	12	%	14	%
	Valero Marketing and Supply Company	10	%	5	%	—	%

Interest_And_Other_Income_Tabl

Interest And Other Income (Tables)	12 Months Ended
	Dec. 31, 2014
Interest and Other Income [Abstract]
Interest And Other Income	The following table provides the components of the Company's interest and other income during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Equity interest in income of EFS Midstream	$	13		$	7		$	2

	Other income	9			9			6

	Deferred compensation plan income	3			6			2

	Interest income	—			—			1

	Loss from vertical integration services (a)	(16		)	(5		)	(12		)
	Total interest and other income	$	9		$	17		$	(1	)

	______________________

	(a)	Loss from vertical integration services represents net margins, after intercompany gains or losses are eliminated, associated with (i) sales of proppant to third-party customers and providing fracture stimulation and well services to working interest owners in Company-operated properties and (ii) extended idle time activities. For the three years ended December 31, 2014, 2013 and 2012, these net margins include $374 million, $285 million and $248 million of gross vertical integration revenues, respectively and $390 million, $290 million and $260 million of total vertical integration costs and expenses, respectively.

Other_Expense_Tables

Other Expense (Tables)	12 Months Ended
	Dec. 31, 2014
Other Expense, Nonoperating [Abstract]
Schedule Of Components Of Other Expense	The following table provides the components of the Company's other expense during the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014		2013		2012
		(in millions)
	Transportation commitment charge (a)	$	46	$	39	$	39

	Other	19		16		20

	Terminated drilling rig contract charges (b)	9		1		16

	Impairment of inventory and other property and equipment (c)	8		62		6

	Above market and idle drilling and well services equipment charges (d)	7		10		33

	Contingency and environmental accrual adjustments	—		9		—

	Total other expense	$	89	$	137	$	114

	____________________

	(a)	Primarily represents firm transportation payments on excess pipeline capacity commitments.

	(b)	Primarily represents charges to terminate rig contracts that were not required to meet planned drilling activities.

	(c)	Primarily represents charges of $8 million and $36 million to reduce excess materials and supplies inventories to their market values for the years ended December 31, 2014 and 2013, respectively, and a charge of $25 million for the year ended December 31, 2013 to reduce the carrying value of Sendero to its estimated fair value. See Notes C and D for additional information on the fair value of Sendero and material and supplies inventory, respectively.

	(d)	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that were above market rates and idle drilling rig and fracture stimulation fleet fees, neither of which were chargeable to joint operations.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Summary Of Open Tax Years, By Jurisdiction	The Company's earliest open years in its key jurisdictions are as follows:



	United States	2013
	Various U.S. states	2009
	South Africa	2009
Schedule Of Income Tax (Provision) Benefit Allocation	The Company's income tax (provision) benefit and amounts separately allocated were attributable to the following items for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Income tax (provision) benefit from continuing operations	$	(556	)	$	213		$	(288	)

	Income tax (provision) benefit from discontinued operations	$	60		$	249		$	181

	Changes in stockholders' equity:
	Net deferred hedge (loss) gain	$	—		$	—		$	(2	)

	Excess tax benefit related to stock-based compensation	$	19		$	18		$	58

	Tax benefit attributable to conversion of 2.875% senior convertible notes	$	—		$	38		$	—

	Tax benefit attributable to 2013 merger with Pioneer Southwest	$	—		$	200		$	—

	Tax attributable to 2008 Pioneer Southwest initial public offering	$	—		$	—		$	(49	)

Income Tax (Provision) Benefit Attributable To Income From Continuing Operations	The Company's income tax (provision) benefit attributable to income from continuing operations consisted of the following for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions)
	Current:
	U.S. federal	$	(3	)	$	(11	)	$	(5	)
	U.S. state	(1		)	—			1

		(4		)	(11		)	(4		)
	Deferred:
	U.S. federal	(537		)	208			(270		)

	U.S. state	(15		)	16			(14		)

		(552		)	224			(284		)

	Income tax (provision) benefit from continuing operations	$	(556	)	$	213		$	(288	)

Schedule Of Effective Income Tax Rate Reconciliation	Reconciliations of the United States federal statutory tax rate to the Company's effective tax rate for income (loss) from continuing operations are as follows for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013			2012
		(in millions, except percentages)
	Income (loss) from continuing operations before income taxes	$	1,597		$	(574	)	$	832

	Less: Net income attributable to noncontrolling interests	—			(39		)	(51		)

	Income (loss) from continuing operations attributable to common stockholders before income taxes	1,597			(613		)	781

	Federal statutory income tax rate	35		%	35		%	35		%
	(Provision) benefit for federal income taxes at the statutory rate	(559		)	215			(273		)

	State income tax (provision) benefit (net of federal tax)	(10		)	10			(8		)

	Premier Silica benefit	21			—			—

	Other	(8		)	(12		)	(7		)
	Income tax (provision) benefit from continuing operations	$	(556	)	$	213		$	(288	)

	Effective income tax rate, excluding income attributable to the noncontrolling interest	35		%	35		%	37		%
Schedule Of Deferred Tax Assets And Deferred Tax Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities related to continuing operations are as follows as of December 31, 2014 and 2013:



		December 31,
		2014			2013
		(in millions)
	Deferred tax assets:
	Net operating loss carryforward (a)	$	330		$	329

	Asset retirement obligations	68			74

	Incentive plans	71			68

	Other	74			74

	Total deferred tax assets	543			545

	Deferred tax liabilities:
	Oil and gas properties, principally due to differences in basis, depletion and the deduction of intangible drilling costs for tax purposes	(1,881		)	(1,570		)
	Other property and equipment, principally due to the deduction of bonus depreciation for tax purposes	(251		)	(255		)
	Net deferred hedge gains	(280		)	(109		)
	Other	(95		)	(103		)
	Total deferred tax liabilities	(2,507		)	(2,037		)
	Net deferred tax liability	$	(1,964	)	$	(1,492	)
	Reflected in accompanying consolidated balance sheets as:
	Current deferred income tax liability	$	(161	)	$	(19	)
	Noncurrent deferred income tax liability	(1,803		)	(1,473		)
	Total	$	(1,964	)	$	(1,492	)
	____________________

	(a)	Net operating loss carryforwards as of December 31, 2014 consist of $927 million of U.S. federal NOLs which expire primarily in 2032 and $120 million of Colorado NOLs which expire between 2027 and 2033.

Net_Income_Loss_Per_Share_Attr1

Net Income (Loss) Per Share Attributable To Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted	The following table is a reconciliation of the Company's net income (loss) attributable to common stockholders to basic and diluted net income (loss) attributable to common stockholders for the years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014				2013			2012
		(in millions)
	Net income (loss) from continuing operations attributable to common stockholders	$	1,041			$	(400	)	$	493

	Participating basic earnings (a)	(10		)		—			(2		)

	Basic and diluted net income (loss) from continuing operations attributable to common stockholders	1,031				(400		)	491

	Basic and diluted net loss from discontinued operations attributable to common stockholders	(111		)		(438		)	(301		)
	Basic and diluted net income (loss) attributable to common stockholders	$	920			$	(838	)	$	190

	______________________

	(a)	Unvested restricted stock awards and Pioneer Southwest phantom unit awards (prior to the December 2013 Pioneer Southwest merger) represent participating securities because they participate in nonforfeitable dividends or distributions with the common equity owners of the Company or Pioneer Southwest, as applicable. Participating share- or unit-based earnings represent the distributed and undistributed earnings of the Company attributable to the participating securities. Unvested restricted stock awards and phantom unit awards do not participate in undistributed net losses as they are not contractually obligated to do so.
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 years ended December 31, 2014, 2013 and 2012:



		Year Ended December 31,
		2014			2013 (a)			2012
		(in millions)
	Weighted average common shares outstanding:
	Basic	144			136			123

	Convertible Senior Notes dilution (b)	—			—			3

	Diluted	144			136			126

	______________________

	(a)	The following common share equivalents were excluded from the weighted average diluted shares for the year ended December 31, 2013 because they would have been anti-dilutive to the loss recorded for the period: (i) 135,190 outstanding options to purchase the Company's common stock, (ii) 200,360 common shares attributable to unvested performance awards and (iii) 1,087,401 common shares related to the 2013 redemption of the Convertible Senior Notes, representing the weighted average portion of the year that is not included in the basic weighted average common shares outstanding.

	(b)	Weighted average common shares outstanding have been increased to reflect the dilutive effect that would have resulted if the Convertible Senior Notes had qualified for and been converted during the year ended December 31, 2012.

Summary_Of_Significant_Account3

Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Dec. 17, 2013	Nov. 04, 2014	Jun. 30, 2010
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Dec. 17, 2013	Rate	Rate
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable - trade	$436	$431
Allowances for doubtful accounts	1	1
Natural gas processing plants number	6
Treating facilities number	8
Operational natural gas processing plants	1
Operational treating facilities	8
Third party revenues, processing plants and treating facilities	56	53	31
Third party expenses, processing plants and treating facilities	24	21	19
Goodwill, Written off Related to Sale of Business Unit	2	24
Stock Issued During Period, Shares, New Issues	5,750,000	10,350,000
Proceeds from issuance of common stock, net of issuance	980	1,281	0
Noncontrolling interest in consolidating subsidiaries	8	13
Net income attributable to noncontrolling interests	0	-39	-51
Pioneer Southwest [Member]
Summary Of Significant Accounting Policies [Line Items]
Share Per Unit Exchange Ratio					0.2325
EFS Midstream [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of interest sold							49.90%
Proceeds from sale of interest in EFS Midstream				46
EFS midstream deferred gain amortization period, years				20
Deferred gain on sale of EFS midstream	$39
Equity Method Investment, Ownership Percentage						50.10%
Wolfcamp [Member]
Summary Of Significant Accounting Policies [Line Items]
Joint Venture Investment Ownership Percentage		40.00%
Limited Partner Interest [Member]
Summary Of Significant Accounting Policies [Line Items]
Partnerships interest					52.40%
General Partner Interest [Member]
Summary Of Significant Accounting Policies [Line Items]
Partnerships interest					0.10%

Summary_Of_Significant_Account4

Summary Of Significant Accounting Policies (Schedule of Inventory) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Schedule of Inventory [Line Items]
Materials and supplies inventories	$223	[1]	$211	[1]
Commodities	18		13
Inventory, Drilling, Noncurrent	0	[2]	-4	[2]
Inventories	241		220
Net materials and supplies inventories reserves	$22		$32

[1]	As of December 31, 2014 and 2013, the Company's materials and supplies inventories were net of valuation allowances of $22 million and $32 million, respectively. See Note D for additional information regarding inventory impairments.
[2]	Included in other noncurrent assets in the Company's accompanying consolidated balance sheet.

Recovered_Sheet1

Summary of Significant Accounting Policies (Schedule of Other Property Plant and Equipment) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$1,391	[1]	$1,224	[1]
Accumulated depreciation property, plant and equipment, other assets	563		458
Fracture Stimulation Fleets	8
Proved and Unproved Sand Leaseholds [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	469	[2]	451	[2]
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	440		345
Wells and Related Equipment and Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	348	[3]	313	[3]
Transportation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	35		41
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	70		48
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$29		$26

[1]	At December 31, 2014 and 2013, other property and equipment was net of accumulated depreciation of $563 million and $458 million, respectively.
[2]	Includes sand mines, facilities and unproved leaseholds that primarily provide the Company and other unrelated customers with proppant used in the fracture stimulation of oil and gas wells.
[3]	Includes well servicing rigs and equipment and fracture stimulation equipment including assets owned by subsidiaries that provide pumping and well services on Company-operated properties. As of December 31, 2014, the Company owned eight fracture stimulation fleets and other oilfield services equipment, including pulling units, fracture stimulation tanks, water transport trucks, hot oilers, blowout preventers, construction equipment and fishing tools.

Summary_Of_Significant_Account5

Summary Of Significant Accounting Policies (Changes of Ownership Interest) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Income (loss) attributable to common stockholders	$930	($838)	$192
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	0	0	-49
Pioneer Southwest noncontrolling interest transferred to APIC		0
Deferred tax benefit associated with the Pioneer Southwest merger	0	200	0
Pioneer Southwest merger transaction costs	-1	-4
Net transfers from noncontrolling interest	-1	365	-49
Net income (loss) attributable to common stockholders and transfers from noncontrolling interest	929	-473	143
Additional Paid-In Capital [Member]
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering			-49
Pioneer Southwest noncontrolling interest transferred to APIC		169
Deferred tax benefit associated with the Pioneer Southwest merger		200
Pioneer Southwest merger transaction costs	-1	-4
Additional Paid-In Capital [Member] \| Pioneer Southwest [Member]
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	0	0	-49
Pioneer Southwest noncontrolling interest transferred to APIC	0	169	0
Deferred tax benefit associated with the Pioneer Southwest merger	0	200	0
Pioneer Southwest merger transaction costs	($1)	($4)	$0

Acquisitions_and_Divestitures_1

Acquisitions and Divestitures (Discontinued Operations Narrative) (Details) (USD $)	12 Months Ended						3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2012	Dec. 17, 2013
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net	$9,000,000		$209,000,000		$46,000,000
Proceeds from disposition of assets, net of cash sold	877,000,000		711,000,000		96,000,000
Issuance of treasury stock to acquire outstanding PSE units, shares			3,960,000
Tangible Asset Impairment Charges	8,000,000	[1]	62,000,000	[1]	6,000,000	[1]
Impairment of oil and gas properties	0		1,495,000,000		0
Gaines Dawson [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net	2,000,000
Proceeds from disposition of assets, net of cash sold	72,000,000
Wolfcamp [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net			181,000,000
Proceeds from disposition of assets, net of cash sold			624,000,000
Joint Venture Investment Ownership Percentage			40.00%
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds			1,800,000,000
Maximum Payments From Related Party For Exploration Drilling And Completion Costs	575,000,000		1,200,000,000
Payments From Related Party For Exploration Drilling And Completion Costs Percent			75.00%
West Panhandle [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net			22,000,000
Proceeds from disposition of assets, net of cash sold			38,000,000
Eagle Ford Shale [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net					43,000,000
Proceeds from disposition of assets, net of cash sold					55,000,000
Other Assets [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net	4,000,000		5,000,000		3,000,000
Lease Contract for Next 12 Months [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Drilling rigs leased	12
Lease Contract for Year 2 [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Drilling rigs leased	8
Discontinued Operations [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net	9,000,000		9,000,000		41,000,000
Impairment of oil and gas properties	305,000,000	[2]	729,000,000	[2]	533,000,000	[2]
Discontinued Operations [Member] \| Hugoton field [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Proceeds from disposition of assets, net of cash sold	328,000,000
Impairment of oil and gas properties	34,000,000
Discontinued Operations [Member] \| Pioneer Alaska [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net					13,000,000
Proceeds from disposition of assets, net of cash sold	267,000,000				10,000,000
Impairment of oil and gas properties	97,000,000		539,000,000
Discontinued Operations [Member] \| Barnett Shale Field [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net			9,000,000
Proceeds from disposition of assets, net of cash sold	150,000,000		34,000,000
Impairment of oil and gas properties	174,000,000		190,000,000		533,000,000
Discontinued Operations [Member] \| Pioneer South Africa [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Gain on disposition of assets, net					29,000,000
Proceeds from disposition of assets, net of cash sold					16,000,000		60,000,000
Sendero [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	31,000,000
Tangible Asset Impairment Charges			25,000,000
Limited Partner Interest [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Partners' Capital Account, Acquisitions	5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	54,000,000
Pioneer Southwest [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Share Per Unit Exchange Ratio								0.2325
Premier Silica [Member]
Discontinued Operations Assets and Liabilities Included in Assets and Liabilities Held for Sale [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net					$297,000,000

[1]	Primarily represents charges of $8 million and $36 million to reduce excess materials and supplies inventories to their market values for the years ended December 31, 2014 and 2013, respectively, and a charge of $25 million for the year ended December 31, 2013 to reduce the carrying value of Sendero to its estimated fair value. See Notes C and D for additional information on the fair value of Sendero and material and supplies inventory, respectively.
[2]	(b)Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.

Acquisitions_and_Divestitures_2

Acquisitions and Divestitures (Components of Discontinued Operations) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Oil and gas	$3,599		$3,088		$2,512
Interest and other	9		17		-1
Gain on disposition of assets, net	9		209		46
Oil and gas production	693		588		532
Production and Ad Valorem Taxes From Discontinued Operations	220		192		169
Depletion, depreciation and amortization	1,047		889		689
Impairment of oil and gas properties	0		1,495		0
Exploration Abandonment and Impairment Expense	177		97		97
General and administrative	333		296		244
Accretion of discount on asset retirement obligations	12		12		8
Interest	184		184		204
Other	89		137		114
Costs and expenses, Total	3,458		4,226		2,177
Current	-4		-11		-4
Deferred	-552		224		-284
Loss from discontinued operations	-111		-438		-301
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Oil and gas	198		329		349
Interest and other	31	[1]	38	[1]	29	[1]
Gain on disposition of assets, net	9		9		41
Total revenues and other income from discontinued operations	238		376		419
Oil and gas production	60		117		107
Production and Ad Valorem Taxes From Discontinued Operations	12		19		19
Depletion, depreciation and amortization	11		122		121
Impairment of oil and gas properties	305	[2]	729	[2]	533	[2]
Exploration Abandonment and Impairment Expense	4		54		109
General and administrative	3		12		6
Accretion of discount on asset retirement obligations	1		1		3
Other	13		9		3
Costs and expenses, Total	409		1,063		901
Income (loss) from discontinued operations before income taxes	-171		-687		-482
Current	0		-6		-10
Deferred	60		255		191
Loss from discontinued operations	-111		-438		-301
Discontinued Operations [Member] \| Pioneer Alaska [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposition of assets, net					13
Impairment of oil and gas properties	97		539
Discontinued Operations [Member] \| Barnett Shale Field [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposition of assets, net			9
Impairment of oil and gas properties	174		190		533
Discontinued Operations [Member] \| Hugoton field [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of oil and gas properties	$34

[1]	(a)Primarily comprised of Alaskan Petroleum Production Tax credits on qualifying capital expenditures.
[2]	(b)Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.

Acquisitions_and_Divestitures_3

Acquisitions and Divestitures (Discontinued Operations Balance Sheet) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Discontinued Operations Balance Sheet Held For Sale [Abstract]
Assets of Disposal Group, Including Discontinued Operation, Current		$58
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net		526
Assets held for sale	0	584
Liabilities of Disposal Group, Including Discontinued Operation, Current		29
Disposal Group, Including Discontinued Operation, Other Liabilities		10
Liabilities held for sale	$0	$39

Disclosures_About_Fair_Value_M2

Disclosures About Fair Value Measurements (Narrative) (Details) (USD $)	12 Months Ended		3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Rate	Dec. 31, 2013	Dec. 31, 2012
Inventory Write-down	$8	$23
discount rate used in impairment calculation	10.00%
Colorado [Member]
Impairment of Long-Lived Assets Held-for-use	50
Barnett Shale Field [Member]
Impairment of Long-Lived Assets Held-for-use			$72

Disclosures_About_Fair_Value_M3

Disclosures About Fair Value Measurements (Assets And Liabilities That Are Measured At Fair Value On A Recurring Basis) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Plan Assets	$70	$64
Assets, Fair Value Disclosure	829	231
Liabilities, Fair Value Disclosure	5	22
Recurring Measurements, (Fair Value, Total)	824	209
Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	759	157
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	2	12
Interest Rate Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		10
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	3	10
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Plan Assets	70	64
Assets, Fair Value Disclosure	70	64
Liabilities, Fair Value Disclosure	0	0
Recurring Measurements, (Fair Value, Total)	70	64
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] \| Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] \| Interest Rate Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Plan Assets	0	0
Assets, Fair Value Disclosure	759	167
Liabilities, Fair Value Disclosure	5	22
Recurring Measurements, (Fair Value, Total)	754	145
Significant Other Observable Inputs (Level 2) [Member] \| Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	759	157
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	2	12
Significant Other Observable Inputs (Level 2) [Member] \| Interest Rate Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		10
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	3	10
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Plan Assets	0	0
Assets, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Recurring Measurements, (Fair Value, Total)	0	0
Significant Unobservable Inputs (Level 3) [Member] \| Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	0	0
Significant Unobservable Inputs (Level 3) [Member] \| Interest Rate Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$0	$0

Disclosures_About_Fair_Value_M4

Disclosures About Fair Value Measurements (Measured On A Nonrecurring Basis) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	$0	($1,495)	$0
Management oil price outlook		80.4	87.09
Management gas price outlook		4.43	4.78
Barnett Shale Field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group			185
Impairment of oil and gas properties			-533
Raton Field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group		534
Impairment of oil and gas properties		($1,495)

Disclosures_About_Fair_Value_M5

Disclosures About Fair Value Measurements Disclosures About Fair Value Measurements (Fair Value of Assets Classified as Held For Sale) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Tangible Asset Impairment Charges	($8)	[1]	($62)	[1]	($6)	[1]
Impairment of oil and gas properties	0		-1,495		0
Sendero [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group			31
Tangible Asset Impairment Charges			-25
Pioneer Alaska [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group	253		351
Barnett Shale Field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group	149		180
Hugoton field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group	328
Discontinued Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	-305	[2]	-729	[2]	-533	[2]
Discontinued Operations [Member] \| Pioneer Alaska [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	-97		-539
Discontinued Operations [Member] \| Barnett Shale Field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	-174		-190
Discontinued Operations [Member] \| Hugoton field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	($34)

[1]	Primarily represents charges of $8 million and $36 million to reduce excess materials and supplies inventories to their market values for the years ended December 31, 2014 and 2013, respectively, and a charge of $25 million for the year ended December 31, 2013 to reduce the carrying value of Sendero to its estimated fair value. See Notes C and D for additional information on the fair value of Sendero and material and supplies inventory, respectively.
[2]	(b)Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.

Disclosures_About_Fair_Value_M6

Disclosures About Fair Value Measurements (Financial Assets and Liabilities Not Carried At Fair Value) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Assets and Liabilities Not Carried At Fair Value [Line Items]
Long-term Debt	$2,665	$2,653
Reported Value Measurement [Member]
Fair Value Assets and Liabilities Not Carried At Fair Value [Line Items]
Long-term Debt	2,665	2,653
Estimate of Fair Value Measurement [Member]
Fair Value Assets and Liabilities Not Carried At Fair Value [Line Items]
Long-term Debt	$2,938	$3,019

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2014		Feb. 13, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Proceeds from Termination of Interest Rate Derivatives	$14
Marketing Oil contracts, in BBL [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount		10,000
Marketing oil contracts, price per BBL [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price		2.99
July 15, 2022 Interest Rate Swaps [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative fixed interest rate	3.95%
Derivative, Variable Interest Rate	1.11%
Notional amount of debt	400
June 30, 2015 Interest Rate Swaps [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative fixed interest rate		2.43%
Swap Contract Notional Amount Fixed Rate of Interest and Variable On-The-Run 10-yr Treasury Rate		200
September 30, 2015 Interest Rate Swaps [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative fixed interest rate		2.46%
Swap Contract Notional Amount Fixed Rate of Interest and Variable On-The-Run 10-yr Treasury Rate		100
Subsequent Event [Member] \| September 30, 2015 Interest Rate Swaps [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative fixed interest rate				2.20%
Swap Contract Notional Amount Fixed Rate of Interest and Variable On-The-Run 10-yr Treasury Rate				$50
Ethane [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for Next Twelve Months [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount		0	[1]
Ethane [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for Year 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount		4,000	[1]
Ethane [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for Next Twelve Months [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price		0
Ethane [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for Year 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price		12.29
Ethane [Member] \| Subsequent Event [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for February Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount				5,000
Ethane [Member] \| Subsequent Event [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for March Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount				500
Ethane [Member] \| Subsequent Event [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for February Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price				7.83
Ethane [Member] \| Subsequent Event [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for March Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price				7.56
Propane [Member] \| Subsequent Event [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for Year 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount				2,000
Propane [Member] \| Subsequent Event [Member] \| NGL contract, in BBLS [Member] \| Swap Contracts for February Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Nonmonetary Notional Amount				8,500
Propane [Member] \| Subsequent Event [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for Year 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price				21.63
Propane [Member] \| Subsequent Event [Member] \| NGL contracts, price per BBL [Member] \| Swap Contracts for February Through December 2015 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Derivative, Swap Type, Average Fixed Price				21.48

[1]	Represent derivative contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices.

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Oil Derivative Contracts Volume And Weighted Average Price) (Details)	Dec. 31, 2014		Feb. 13, 2015
Rollfactor Swap Contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Swap Multiple Second Nearby Month	0.6667
Swap Multiple Third Nearby Month	0.3333
Oil contracts, price per bbl [Member] \| Swap Contracts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Swap Type, Average Fixed Price	71.18
Oil contracts, price per bbl [Member] \| Swap Contracts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Average Cap Price	101.36
Derivative, Average Floor Price	86.82
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member] \| Short Put [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Notional Amount, Price Per Unit	75.73
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Average Cap Price	96.46
Derivative, Average Floor Price	85.47
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 [Member] \| Short Put [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Notional Amount, Price Per Unit	74.35
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 - Extendible for Year 3 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Average Cap Price	100.08
Derivative, Average Floor Price	90
Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 - Extendible for Year 3 [Member] \| Short Put [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Notional Amount, Price Per Unit	80
Oil contracts, price per bbl [Member] \| Rollfactor Swap Contracts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Swap Type, Average Fixed Price	0.06	[1]
Oil contracts, price per bbl [Member] \| Rollfactor Swap Contracts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Swap Type, Average Fixed Price	0	[1]
Oil contracts [Member] \| Swap Contracts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	82,000
Oil contracts [Member] \| Swap Contracts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	0
Oil contracts [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	13,767	[2],[3]
Oil contracts [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	73,000	[2],[3]
Oil contracts [Member] \| Collar Contracts With Short Puts for Year 2 - Extendible for Year 3 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	5,000
Oil contracts [Member] \| Rollfactor Swap Contracts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	36,575
Oil contracts [Member] \| Rollfactor Swap Contracts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount	0
Subsequent Event [Member] \| Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Average Cap Price			78.33
Derivative, Average Floor Price			66.5
Subsequent Event [Member] \| Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member] \| Short Put [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Notional Amount, Price Per Unit			40
Subsequent Event [Member] \| Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Average Cap Price			77.41
Derivative, Average Floor Price			66.58
Subsequent Event [Member] \| Oil contracts, price per bbl [Member] \| Collar Contracts With Short Puts for Year 2 [Member] \| Short Put [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Notional Amount, Price Per Unit			41.55
Subsequent Event [Member] \| Oil contracts [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount			3,000	[1],[2],[3]
Subsequent Event [Member] \| Oil contracts [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount			55,000	[1],[2],[3]

[1]	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.
[2]	During the period from January 1, 2015 through February 13, 2015, the Company converted (i) 3,000 Bbls per day of 2015 collar contracts with short puts into new 2015 collar contract with short puts with a ceiling price of $78.33 per Bbl, a floor price of $66.50 per Bbl and a short put price of $40.00 per Bbl and (ii) 55,000 Bbls per day of 2016 collar contracts with short puts into new 2016 collar contracts with short puts with a ceiling price of $77.41 per Bbl, a floor price of $66.58 per Bbl and a short put price of $41.55 per Bbl.
[3]	Counterparties have the option to extend for an additional year 5,000 Bbls per day of 2015 collar contracts with short puts with a ceiling price of $100.08 per Bbl, a floor price of $90.00 per Bbl and a short put price of $80.00 per Bbl. The option to extend is exercisable on December 31, 2015. These contracts give the counterparties the option to extend the contracts under the same terms for an additional year if the option to extend is exercised by the counterparties on December 31, 2015.

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Gas Derivative Contracts Volume And Weighted Average Price) (Details)	Dec. 31, 2014
Gas contracts, in MMBTU [Member] \| Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	20,000
Gas contracts, in MMBTU [Member] \| Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	70,000
Gas contracts, in MMBTU [Member] \| Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0
Gas contracts, in MMBTU [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	285,000
Gas contracts, in MMBTU [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	20,000
Gas contracts, in MMBTU [Member] \| Collar Contracts With Short Puts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0
Gas contracts, price per MMBTU [Member] \| Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	4.31
Gas contracts, price per MMBTU [Member] \| Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	4.06
Gas contracts, price per MMBTU [Member] \| Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Average Cap Price	5.07
Derivative, Average Floor Price	4
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Next Twelve Months [Member] \| Short Put [Member]
Derivative [Line Items]
Derivative, Notional Amount, Price Per Unit	3
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	5.36
Derivative, Average Floor Price	4
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Year 2 [Member] \| Short Put [Member]
Derivative [Line Items]
Derivative, Notional Amount, Price Per Unit	3
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Year 3 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Gas contracts, price per MMBTU [Member] \| Collar Contracts With Short Puts for Year 3 [Member] \| Short Put [Member]
Derivative [Line Items]
Derivative, Notional Amount, Price Per Unit	0
Gulf Coast [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	20,000	[1]
Gulf Coast [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	[1]
Gulf Coast [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	[1]
Gulf Coast [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Gulf Coast [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Gulf Coast [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Mid-Continent [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	95,000	[1]
Mid-Continent [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	15,000	[1]
Mid-Continent [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	30,000	[1]
Mid-Continent [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	-0.24
Mid-Continent [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	-0.32
Mid-Continent [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	-0.34
Permian Basin [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	10,000	[1]
Permian Basin [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	[1]
Permian Basin [Member] \| Gas contracts, in MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	[1]
Permian Basin [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Next Twelve Months [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	-0.13
Permian Basin [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0
Permian Basin [Member] \| Gas contracts, price per MMBTU [Member] \| Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price	0

[1]	Represent swaps that fix the basis differentials between the index prices at which the Company sells its Gulf Coast, Mid-Continent and Permian Basin gas, respectively, and the NYMEX Henry Hub index price used in gas swap and collar contracts.

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Offsetting Assets and Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative Asset, Current	$578	$76
Derivative Asset, Noncurrent	181	91
Derivative Liability, Current	3	12
Derivative Liability, Noncurrent	2	10
Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	759	167
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	5	22
Derivative Current [Member] \| Not Designated As Hedging Instruments [Member] \| Commodity Price Derivatives [Member]
Derivative [Line Items]
Total derivatives, Asset	579	73
Total derivatives, Liability	1	19
Derivative Assets Offset In Balance Sheet	-1	-7
Derivative Liabilities Offset In Balance Sheet	1	7
Derivative Asset, Current	578	66
Derivative Liability, Current	0	12
Derivative Current [Member] \| Not Designated As Hedging Instruments [Member] \| Interest Rate Derivatives [Member]
Derivative [Line Items]
Total derivatives, Asset		10
Total derivatives, Liability	3
Derivative Assets Offset In Balance Sheet		0
Derivative Liabilities Offset In Balance Sheet	0
Derivative Asset, Current		10
Derivative Liability, Current	3
Derivative Noncurrent [Member] \| Not Designated As Hedging Instruments [Member] \| Commodity Price Derivatives [Member]
Derivative [Line Items]
Total derivatives, Asset	182	95
Total derivatives, Liability	3	4
Derivative Assets Offset In Balance Sheet	-1	-4
Derivative Liabilities Offset In Balance Sheet	1	4
Derivative Asset, Noncurrent	181	91
Derivative Liability, Noncurrent	2	0
Derivative Noncurrent [Member] \| Not Designated As Hedging Instruments [Member] \| Interest Rate Derivatives [Member]
Derivative [Line Items]
Total derivatives, Asset		15
Total derivatives, Liability		25
Derivative Assets Offset In Balance Sheet		-15
Derivative Liabilities Offset In Balance Sheet		15
Derivative Asset, Noncurrent		0
Derivative Liability, Noncurrent		$10

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Derivative Obligations Under Terminated Hedge Arrangements) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Derivative gains, net	$712	$4	$330
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	0	0	-5
Interest Rate Derivatives [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax			-2
Interest Rate Derivatives [Member] \| Interest Expense [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	0	0	-2
Interest Rate Derivatives [Member] \| Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains, net	15	10	-23
Commodity Price Derivatives [Member] \| Oil And Gas revenue [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	0	0	-3
Commodity Price Derivatives [Member] \| Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains, net	$697	($6)	$353

Schedule_of_Derivative_Assets_

Schedule of Derivative Assets and Liabilities by Counterparty (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$754
JP Morgan Chase [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	130
J. Aron & Company [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	120
Merrill Lynch [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	101
Citibank, N.A. [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	98
Morgan Stanley [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	69
BMO Financial Group [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	47
Barclays Capital [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	45
Wells Fargo Bank, N.A. [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	44
Societe Generale [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	39
Macquarie Bank [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	19
Credit Suisse [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	18
Toronto Dominion [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	12
Den Norske [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	11
Royal Bank of Canada [Member]
Schedule of Derivative Assets and Liabilities by Counterparty [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$1

Exploratory_Well_Costs_Capital

Exploratory Well Costs (Capitalized Exploratory Well And Project Activity) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Capitalized Exploratory Well Costs, Beginning Balance	$159	[1]	$213	[1]	$108
Capitalized Exploratory Well Cost, Additions Pending Determination of Proved Reserves	1,860		1,220		926
Reclassification due to determination of proved reserves	-1,628		-1,045		-790
Capitalized Exploratory Well Cost Assets Disposition	-47		-93		0
Impairment of oil and gas properties	0		1,495		0
Exploratory well costs charged to exploration expense	-26	[2]	-49	[2]	-31	[2]
Capitalized Exploratory Well Costs, Ending Balance	305	[1]	159	[1]	213	[1]
Exploration Abandonment and Impairment Expense	177		97		97
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net			526
Discontinued Operations [Member]
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Impairment of oil and gas properties	305	[3]	729	[3]	533	[3]
Exploration Abandonment and Impairment Expense	4		54		109
Capitalized exploratory costs [Member]
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Impairment of oil and gas properties	-13		-87		0
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net			60
Capitalized exploratory costs [Member] \| Discontinued Operations [Member]
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Exploration Abandonment and Impairment Expense			$43		$22

[1]	The December 31, 2013 balance includes $60 million of capitalized exploratory well costs classified as held for sale in the accompanying consolidated balance sheet as of December 31, 2013.
[2]	Includes exploration and abandonment expense of $43 million and $22 million in 2013 and 2012, respectively, that is included in discontinued operations for each respective period in the accompanying consolidated statements of operations.
[3]	(b)Represents noncash impairment charges of $97 million and $539 million on Pioneer Alaska net assets during the years ended December 31, 2014 and 2013, respectively, noncash impairment charges of $174 million, $190 million and $533 million on the Company's net assets in the Barnett Shale field during the years ended December 31, 2014, 2013 and 2012, respectively, and a noncash impairment charge of $34 million on the Company's net assets in the Hugoton field during the year ended December 31, 2014. See Note D for additional information regarding the noncash impairment charges.

Exploratory_Well_Costs_Capital1

Exploratory Well Costs (Capitalized Exploratory Costs And the Number Of Projects For Which Exploratory Costs Have Been Capitalized) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
One year or less	$305		$116		$191
More than one year	0		43		22
Capitalized exploratory well costs, total suspended	305	[1]	159	[1]	213	[1]	108
Number of projects with exploratory well costs that have been suspended for a period greater than one year	0		1		1
Nuna [Member]
More than one year			43
Oooguruk [Member]
More than one year					$22

[1]	The December 31, 2013 balance includes $60 million of capitalized exploratory well costs classified as held for sale in the accompanying consolidated balance sheet as of December 31, 2013.

LongTerm_Debt_Narrative_Detail

Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended			6 Months Ended
Share data in Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013
Line of credit facility, maximum borrowing capacity	$1,500,000,000
Outstanding borrowings under the Credit Facility	0
Borrowings under long-term debt	523,000,000	467,000,000	1,777,000,000
Pioneer Credit Facility [Member]
Federal fund rate	0.50%
Alternate base rate spread	0.50%
Applicable margin	1.50%
Letters of credit outstanding under the Credit Facility, interest percentage	0.13%
Unused portion, fee percentage	0.25%
Swing Line Loans [Member] \| Pioneer Credit Facility [Member]
Maximum outstanding borrowings under the Credit Facility	150,000,000
2.875% Convertible Senior Notes Due 2038 [Member]
Convertible debt			480,000,000
Principal amount of notes tendered for conversion				479,000,000
Cash Paid To Conversion Of Convertible Senior Notes				479,000,000
Shares received for conversion of debt				4.4
Cash Paid To Redeem Convertible Debt				1,000,000
Interest expense relating to the contractual interest coupon and unamortized discount		$9,400,000	$33,500,000
Debt instrument, effective interest rate, percentage	6.75%
Senior Notes, interest rate, percentage	2.88%
Total Debt To Book Capitalization [Member] \| Pioneer Credit Facility [Member]
Debt instrument covenant description	0.6

LongTerm_Debt_Components_Of_Lo

Long-Term Debt (Components Of Long-Term Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Outstanding debt principal balances, gross	$2,690	$2,690
Issuance discounts and premiums, net	-24	-36
Net deferred fair value hedge losses	-1	-1
Long-term Debt	2,665	2,653
Outstanding borrowing	0
5.875% Senior Notes Due 2016 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	455	455
Senior notes, interest rate	5.88%
6.65% Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	485	485
Senior notes, interest rate	6.65%
6.875% Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	450	450
Senior notes, interest rate	6.88%
7.500% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	450	450
Senior notes, interest rate	7.50%
3.95% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	600	600
Senior notes, interest rate	3.95%
7.20% Senior Notes Due 2028 [Member]
Debt Instrument [Line Items]
Issuance of senior notes	$250	$250
Senior notes, interest rate	7.20%

LongTerm_Debt_Principal_Maturi

Long-Term Debt (Principal Maturities Of Long-Term Debt) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Debt Disclosure [Abstract]
2015	$0
2016	455
2017	485
2018	450
2019	0
Thereafter	$1,300

LongTerm_Debt_Interest_Expense

Long-Term Debt (Interest Expenses) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Cash payments for interest	$193		$183		$168
Accretion/amortization of discounts or premiums on loans	12		12		28
Amortization of net deferred hedge losses	0	[1]	0	[1]	2	[1]
Amortization of capitalized loan fees	5		5		6
Net changes in accruals	-22		-6		11
Interest incurred	188		194		215
Less capitalized interest	-4		-10		-11
Interest	184		184		204
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	0		0		-5
Interest Rate Derivatives [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax					($2)

[1]	Includes interest rate derivative hedges of $2 million for the period ended December 31, 2012 that were reclassified from AOCI - Hedging into earnings upon expiration (see Note E).

Incentive_Plans_Narrative_Deta

Incentive Plans (Narrative) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Matching contributions vesting period in years	4
Deferred Compensation Arrangement with Individual, Compensation Expense	$110		$112		$86
Unrecognized share-based compensation expense	122
Restricted Units Vesting Schedule	3 years 0 months 0 days
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	2		2		2
Employee stock purchase plan contribution limit	15.00%
Employee stock purchase plan participants purchase price percent	15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	475,362
Approved and authorized awards	1,250,000
Restricted Stock Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	28		40		23
Unrecognized share-based compensation expense	25
Number of Shares granted	140,093
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	38		26		14
Amount of liabilities attributable to liability awards included in accounts payable	23		33
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares granted	546,710
Restricted Stock Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	65		57		50
Number of Shares granted	406,617
Number of unvested shares	170,210
Weighted Average Grant-Date Fair Value, Shares granted	$184.39		$134.17		$113.09
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	88		69		137
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	2	[1]	3	[1]	4	[1]
Weighted Average Grant-Date Fair Value, Shares granted					$56.29
Option awards contract life	10
Average dividend yield	7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercised, Intrinsic Value	12		21		17
Performance Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant-Date Fair Value, Shares granted	$232.20		$189.23		$172.57
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	13		19		19
Pioneer Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,361,918
Approved and authorized awards	9,100,000
PSE Employee Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	654,842
Approved and authorized awards	678,034
Deferred Compensation Retirement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Matching contributions percent	100.00%
Matching contributions	3		3		2
Deferred Compensation Retirement Plan [Member] \| Base Salary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Participants annual salary contributions, percentage	25.00%
Deferred Compensation Retirement Plan [Member] \| Bonus [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Participants annual salary contributions, percentage	100.00%
401(k) Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Participants annual salary contributions, percentage	80.00%
Matching contributions percent	200.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	5.00%
Deferred Compensation Arrangement with Individual, Compensation Expense	$33		$30		$25
Officer [Member] \| Deferred Compensation Retirement Plan [Member] \| Base Salary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	10.00%
Key Employee [Member] \| Deferred Compensation Retirement Plan [Member] \| Bonus [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	8.00%

[1]	(a)Cash proceeds received from stock option exercises during 2014, 2013 and 2012 amounted to $6 million, $5 million and $3 million, respectively.

Incentive_Plans_Number_Of_Shar

Incentive Plans (Number Of Shares Available Under The Company's Long Term Incentive Plan) (Details) (Pioneer Long-Term Incentive Plan [Member])	104 Months Ended
	Dec. 31, 2014
Pioneer Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Approved and authorized awards	9,100,000
Shares issued	-6,738,082
Awards available for future grant	2,361,918

Incentive_Plans_Number_Of_Awar

Incentive Plans (Number Of Awards Available Under Company's Long Term Incentive Plan) (Details) (PSE Employee Long Term Incentive Plan [Member])	12 Months Ended
	Dec. 31, 2014
PSE Employee Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Approved and authorized awards	678,034
Shares issued	-23,192
Awards available for future grant	654,842

Incentive_Plans_Schedule_Of_Em

Incentive Plans (Schedule Of Employee Stock Purchase Plan) (Details) (Employee Stock [Member])	216 Months Ended
	Dec. 31, 2014
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Approved and authorized shares	1,250,000
Shares issued	-774,638
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	475,362

Incentive_Plans_Schedule_of_Co

Incentive Plans (Schedule of Compensation Expense for Each Type of Incentive Award) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	$110		$112		$86
Income Tax (Expense) Benefit	-556		213		-288
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	6		5		3
Restricted Stock Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	65		57		50
Restricted Stock Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	28		40		23
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	2	[1]	3	[1]	4	[1]
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	13		9		6
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	2		2		2
Other Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	0		1		1
Compensation Expense For Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income Tax (Expense) Benefit	$33		$36		$28

[1]	(a)Cash proceeds received from stock option exercises during 2014, 2013 and 2012 amounted to $6 million, $5 million and $3 million, respectively.

Incentive_Plans_Schedule_Of_Re

Incentive Plans (Schedule Of Restricted Stock Award Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares/Units, Outstanding at beginning of year	1,371,207
Number of Shares granted	406,617
Forfeitures, number of shares	-79,777
Awards vested	-464,508
Number of Shares/Units, Outstanding at end of year	1,233,539	1,371,207
Weighted Average Grant-Date Fair Value, Outstanding at beginning of year	$117.09
Weighted Average Grant-Date Fair Value, Shares granted	$184.39	$134.17	$113.09
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$134.25
Weighted Average Grant-Date Fair Value, Shares vested	$108.79
Weighted Average Grant-Date Fair Value, Outstanding at end of year	$140.57	$117.09
Restricted Stock Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares/Units, Outstanding at beginning of year	422,382
Number of Shares granted	140,093
Forfeitures, number of shares	-33,052
Awards vested	-201,336
Number of Shares/Units, Outstanding at end of year	328,087

Incentive_Plans_Schedule_Of_We

Incentive Plans (Schedule Of Weighted-Average Assumptions To Estimate The Fair Value) (Details) (Stock Options [Member])	12 Months Ended
	Dec. 31, 2012
	Rate
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option life - years	7 years 0 months 1 day
Volatility	49.40%
Risk-free interest rate	1.50%
Dividend yield	0.40%

Incentive_Plans_Schedule_Of_St

Incentive Plans (Schedule Of Stock Options Awards Activity) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised	0	0	0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at beginning of year	289,927
Options exercised	-90,869
Number of Shares, Outstanding and expected to vest at end of year	199,058
Number of Shares, Exercisable at end of year	106,278
Weighted Average Exercise Price, Outstanding at beginning of year	74.9
Weighted Average Exercise Price, Options exercised	69.19
Weighted Average Exercise Price, Outstanding and expected to vest at end of year	77.51
Weighted Average Exercise Price, Exercisable at end of year	45.86
Weighted Average Remaining Contractual Life, Outstanding and expected to vest at end of year	5 years 11 months 15 days
Weighted Average Remaining Contractual Life, Exercisable at end of year	4 years 11 months 1 day
Aggregate Intrinsic Value, Outstanding and expected to vest at end of year	14
Aggregate Intrinsic Value, Exercisable at end of year	11

Incentive_Plans_Schedule_Of_As

Incentive Plans (Schedule Of Assumptions To Estimate The Fair Value) (Details) (Performance Units [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Rate	Rate	Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.62%	0.40%	0.40%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of volatilities	41.50%	42.90%	49.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of volatilities	29.00%	30.40%	33.60%

Incentive_Plans_Schedule_Of_Pe

Incentive Plans (Schedule Of Performance Unit Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
	Rate		Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued	152,000,000		146,000,000
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares/Units, Outstanding at beginning of year	134,476	[1]
Number of Units granted	67,182	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	-1,153	[1]
Awards vested	-44,949
Number of Shares/Units, Outstanding at end of year	154,733	[1]
Weighted Average Grant-Date Fair Value, Outstanding at beginning of year	$183.66
Weighted Average Grant-Date Fair Value, Units granted	$232.20
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$189.23
Weighted Average Grant Date Fair Value, Units vested	$172.87	[2]
Weighted Average Grant-Date Fair Value, Outstanding at end of year	$207.88
Performance percentage of actual payout minimum	0.00%
Performance percentage to reach maximum	250.00%
Number of shares earned for each vested award	2
Common stock, shares issued	89,898
Performance Units, including Retirement Deferred Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vested	-45,772	[1],[2]
Retirement Deferred Performance Units [Member] [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vested	-823

[1]	(a)These amounts reflect the number of performance units granted. The actual payout of shares may be between zero percent and 250 percent of the performance units granted depending upon the total shareholder return ranking of the Company compared to peer companies at the vesting date.
[2]	(b)On DecemberB 31, 2014, the service period lapsed on 44,949 of these performance unit awards, which does not include 823 retirement deferred shares scheduled for release on December 31, 2015. The lapsed units earned two shares for each vested award representing 89,898 aggregate shares of common stock issued on JanuaryB 2, 2015.

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligations, Beginning Balance	$194		$198		$137
AssetRetirementObligationLiabilitiesAcquiredInBusinessCombination	6		0		10
Liabilities incurred	5		6		10
Changes in estimates	7	[1]	8	[1]	52	[1]
Disposition of wells	-14		-16		-2
Liabilities settled	-21		-15		-18
Accretion of discount on continuing operations	12		12		8
Accretion of discount on discontinued operations	0		1		1
Asset Retirement Obligations, Ending Balance	189		194		198
Asset retirement obligations, current portion	$28		$19

[1]	(a)The changes in the 2014, 2013 and 2012 estimates are primarily due to increases in abandonment cost estimates based on recent actual costs incurred to abandon wells and declines in the credit-adjusted risk-free discount rates used to value the Company's asset retirement obligations. The increases in the 2014 and 2012 estimates were further impacted by declines in oil, NGL and gas prices used to calculate proved reserves, which had the effect of shortening the economic life of certain wells and increasing the present value of future retirement obligations. The increases in 2013 estimates were partially offset by higher commodity prices, which had the effect of lengthening the economic life of certain wells and decreasing the present value of future retirement obligations.

Commitments_And_Contingencies_1

Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Current annual salaries of officers and key employees	$41

Commitments_And_Contingencies_2

Commitments And Contingencies Commitments and Contingencies (Future Minimum Drilling Commitments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Other Commitment, Due in Next Twelve Months	$303
Other Commitment, Due in Second Year	197
Other Commitment, Due in Third Year	113
Other Commitment, Due in Fourth Year	32
Other Commitment, Due in Fifth Year	2
Other Commitment, Due Thereafter	$0

Commitments_And_Contingencies_3

Commitments And Contingencies (Future Minimum Lease Commitments) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies [Line Items]
Operating Leases, Rent Expense	$66	$58	$48
Year 1 Minimum Lease Commitments	30
Year 2 Minimum Lease Commitments	22
Year 3 Minimum Lease Commitments	20
Year 4 Minimum Lease Commitments	19
Year 5 Minimum Lease Commitments	19
Thereafter	27
Lease Payments Discontinued Operations [Member]
Commitments And Contingencies [Line Items]
Operating Leases, Rent Expense	$9	$10	$8

Commitments_And_Contingencies_4

Commitments And Contingencies (Future Minimum Transportation Fees) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Year 1 Transportation Agreements	$455
Year 2 Transportation Agreements	486
Year 3 Transportation Agreements	364
Year 4 Transportation Agreements	332
Year 5 Transportation Agreements	325
Thereafter	$1,011
Oil and Gas Delivery Commitments and Contracts, Daily Production	50,000

Related_Party_Transactions_Nar

Related Party Transactions (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from Related Parties	$3	$3	$2
Proceeds from Equity Method Investment, Dividends or Distributions	50	25
EFS Midstream [Member]
Cost reimbursement fixed	3	3	2
Cost reimbursement variable	18	16	12
Payments to Acquire Property, Plant, and Equipment		3
Gathering And Treating Fees [Member] \| EFS Midstream [Member]
Related party transaction expenses paid	$103	$81	$59

Major_Customers_Consolidated_O

Major Customers (Consolidated Oil, NGL And Gas Revenues) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Rate	Rate	Rate
Plains Marketing LP [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	24.00%	26.00%	25.00%
Occidental Energy Marketing Inc [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	13.00%	12.00%	13.00%
Enterprise Products Partners L.P. [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	11.00%	12.00%	14.00%
Valero Marketing and Supply Company [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	10.00%	5.00%	0.00%

Interest_And_Other_Income_Inte

Interest And Other Income (Interest And Other Income) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Interest and Other Income [Abstract]
Equity interest in income (loss) of EFS Midstream	$13		$7		$2
Other income	9		9		6
Deferred compensation plan income	3		6		2
Interest income	0		0		1
Third-party income (loss) from vertical integration services	-16	[1]	-5	[1]	-12	[1]
Total interest and other income	9		17		-1
GrossRevenuesIncludedInThirdPartyIncomeFromVerticalIntegrationServices	374		285		248
GrossExpensesIncludedInThirdPartyIncomeFromVerticalIntegrationServices	$390		$290		$260

[1]	Loss from vertical integration services represents net margins, after intercompany gains or losses are eliminated, associated with (i) sales of proppant to third-party customers and providing fracture stimulation and well services to working interest owners in Company-operated properties and (ii) extended idle time activities. For the three years ended December 31, 2014, 2013 and 2012, these net margins include $374 million, $285 million and $248 million of gross vertical integration revenues, respectively and $390 million, $290 million and $260 million of total vertical integration costs and expenses, respectively.

Other_Expense_Schedule_Of_Comp

Other Expense (Schedule Of Components Of Other Expense) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Transportation commitment charge	$46	[1]	$39	[1]	$39	[1]
Other	19		16		20
Terminated Drilling Rig Expense	9	[2]	1	[2]	16	[2]
Tangible Asset Impairment Charges	8	[3]	62	[3]	6	[3]
Above market drilling and rig termination costs	7	[4]	10	[4]	33	[4]
Contingency and environmental accrual adjustments	0		9		0
Total other expense	89		137		114
Inventory [Member]
Tangible Asset Impairment Charges	8		36
Sendero [Member]
Tangible Asset Impairment Charges			$25

[1]	Primarily represents firm transportation payments on excess pipeline capacity commitments.
[2]	Primarily represents charges to terminate rig contracts that were not required to meet planned drilling activities.
[3]	Primarily represents charges of $8 million and $36 million to reduce excess materials and supplies inventories to their market values for the years ended December 31, 2014 and 2013, respectively, and a charge of $25 million for the year ended December 31, 2013 to reduce the carrying value of Sendero to its estimated fair value. See Notes C and D for additional information on the fair value of Sendero and material and supplies inventory, respectively.
[4]	Primarily represents expenses attributable to the portion of Pioneer's contracted drilling rig rates that were above market rates and idle drilling rig and fracture stimulation fleet fees, neither of which were chargeable to joint operations.

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Payments for income taxes, net of tax refunds received	$22	$12	$32
Unrecognized tax benefit recognized in period	21	0	0
Unrecognized Tax Benefits	0
Pioneer South Africa [Member]
Operating Loss Carryforwards [Line Items]
Payments for income taxes, net of tax refunds received			$10

Income_Taxes_Summary_Of_Open_T

Income Taxes (Summary Of Open Tax Years, By Jurisdiction) (Details)	12 Months Ended
	Dec. 31, 2014
United States [Member]
Income Tax Contingency [Line Items]
Open tax years, by jurisdiction	2013
Various U.S. States [Member]
Income Tax Contingency [Line Items]
Open tax years, by jurisdiction	2009
South Africa [Member]
Income Tax Contingency [Line Items]
Open tax years, by jurisdiction	2009

Income_Taxes_Schedule_Of_Incom

Income Taxes (Schedule Of Income Tax (Provision) Benefit Allocation) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income tax benefit (provision)	($556)	$213	($288)
Income tax from discontinued operations	60	249	181
Net deferred hedge loss	0	0	-2
Tax benefits related to stock-based compensation	19	18	58
Income Tax Effects Allocated Directly to Equity, Equity Transactions	0	38	0
Deferred tax benefit associated with the Pioneer Southwest merger	0	200	0
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	$0	$0	($49)

Income_Taxes_Income_Tax_Provis

Income Taxes (Income Tax (Provision) Benefit Attributable To Income From Continuing Operations) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. federal	($3)	($11)	($5)
U.S. state	-1	0	1
Current income tax (provision) benefit	-4	-11	-4
U.S. federal	-537	208	-270
U.S. state	-15	16	-14
Deferred income tax (provision) benefit	-552	224	-284
Income tax (provision) benefit	($556)	$213	($288)

Income_Taxes_Schedule_Of_Effec

Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Rate	Rate	Rate
Income Tax Disclosure [Abstract]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	$1,597	($574)	$832
Net Income Attributable to Noncontrolling Interest	0	-39	-51
Income (loss) from continuing operations before tax	1,597	-613	781
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
Income Tax Reconciliation, Income Tax (Expense) Benefit, at Federal Statutory Income Tax Rate	-559	215	-273
Income Tax Reconciliation, State and Local Income Taxes	-10	10	-8
Unrecognized tax benefit recognized in period	21	0	0
Income Tax Reconciliation, Other Adjustments	-8	-12	-7
Income Tax (Expense) Benefit	($556)	$213	($288)
Effective Income Tax Rate, Continuing Operations	35.00%	35.00%	37.00%

Income_Taxes_Schedule_Of_Defer

Income Taxes (Schedule Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Valuation Allowance [Line Items]
Net operating loss carryforward	$330	[1]	$329	[1]
Asset retirement obligations	68		74
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	71		68
Other	74		74
Total deferred tax assets	543		545
Oil and gas properties, principally due to differences in basis, depletion and the deduction of intangible drilling costs for tax purposes	-1,881		-1,570
Other property and equipment, principally due to the deduction of bonus depreciation for tax purposes	-251		-255
Net deferred hedge gains	-280		-109
State taxes and other	-95		-103
Total deferred tax liabilities	-2,507		-2,037
Net deferred tax liability	-1,964		-1,492
Current deferred income tax liability	-161		-19
Non-current deferred income tax liability	-1,803		-1,473
UNITED STATES
Valuation Allowance [Line Items]
Net operating loss carryforward	927
COLORADO
Valuation Allowance [Line Items]
Net operating loss carryforward	$120

[1]	Net operating loss carryforwards as of December 31, 2014 consist of $927 million of U.S. federal NOLs which expire primarily in 2032 and $120 million of Colorado NOLs which expire between 2027 and 2033

Net_Income_Loss_Per_Share_Attr2

Net Income (Loss) Per Share Attributable To Common Stockholders (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Statement Operating Activities Segment [Line Items]
Income (loss) from continuing operations, net of tax	$1,041		($400)		$493
Net Income (Loss) Available to Common Stockholders, Basic	920		-838		190
Diluted income (loss) attributable to common stockholders	920		-838		190
Segment, Continuing Operations [Member]
Statement Operating Activities Segment [Line Items]
Income (loss) from continuing operations, net of tax	1,041		-400		493
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	-10	[1]	0	[1]	-2	[1]
Net Income (Loss) Available to Common Stockholders, Basic	1,031		-400		491
Diluted income (loss) attributable to common stockholders	1,031		-400		491
Discontinued Operations [Member]
Statement Operating Activities Segment [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	-111		-438		-301
Diluted income (loss) attributable to common stockholders	($111)		($438)		($301)

[1]	(a)Unvested restricted stock awards and Pioneer Southwest phantom unit awards (prior to the December 2013 Pioneer Southwest merger) represent participating securities because they participate in nonforfeitable dividends or distributions with the common equity owners of the Company or Pioneer Southwest, as applicable. Participating share- or unit-based earnings represent the distributed and undistributed earnings of the Company attributable to the participating securities. Unvested restricted stock awards and phantom unit awards do not participate in undistributed net losses as they are not contractually obligated to do so.

Net_Income_Loss_Per_Share_Attr3

Net Income (Loss) Per Share Attributable To Common Stockholders (Reconciliation Of Basic To Diluted Weighted Average Common Shares Outstanding) (Details)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Basic	144,000,000		136,000,000	[1]	123,000,000
Convertible notes dilution	0	[2]	0	[1],[2]	3,000,000	[2]
Diluted	144,000,000		136,000,000	[1]	126,000,000
Stock Options [Member]
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount			135,190
Unvested Performance units [Member]
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount			200,360
Conversion rights [Member]
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount			1,087,401

[1]	(a)The following common share equivalents were excluded from the weighted average diluted shares for the year ended December 31, 2013 because they would have been anti-dilutive to the loss recorded for the period: (i) 135,190 outstanding options to purchase the Company's common stock, (ii) 200,360 common shares attributable to unvested performance awards and (iii) 1,087,401 common shares related to the 2013 redemption of the Convertible Senior Notes, representing the weighted average portion of the year that is not included in the basic weighted average common shares outstanding.
[2]	Weighted average common shares outstanding have been increased to reflect the dilutive effect that would have resulted if the Convertible Senior Notes had qualified for and been converted during the year ended December 31, 2012.