Pioneer Natural Resources (PXD) 10-Q 1 Aug 17 2017 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 28, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	PXD
Entity Registrant Name	PIONEER NATURAL RESOURCES CO
Entity Central Index Key	1,038,357
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		170,097,565

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents, at Carrying Value	$ 660	$ 1,118
Short-term Investments	1,539	1,441
Accounts receivable:
Trade, net	491	517
Due from affiliates	0	1
Income taxes receivable	1	3
Inventories	192	181
Other current assets:
Derivatives Assets, Current	156	14
Other	25	23
Total current assets	3,064	3,298
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	18,983	18,566
Unproved properties	518	486
Accumulated depletion, depreciation and amortization	(8,505)	(8,211)
Total property, plant and equipment	10,996	10,841
Long-term Investments	187	420
Goodwill	270	272
Property, Plant and Equipment, Net	1,622	1,529
Other assets:
Derivative Assets, Noncurrent	29	0
Other, net	103	99
Assets, Total	16,271	16,459
Accounts payable:
Trade	881	741
Due to affiliates	63	134
Interest payable	59	68
Current portion of long-term debt	449	485
Other current liabilities:
Derivative Liabilities, Current	3	77
Other	103	61
Total current liabilities	1,558	1,566
Long-term Debt, Excluding Current Maturities	2,281	2,728
Derivative Liabilities, Noncurrent	1	7
Deferred income taxes	1,487	1,397
Other liabilities	342	350
Stockholders' equity:
Common stock, $.01 par value	2	2
Additional paid-in capital	8,937	8,892
Treasury stock at cost	(254)	(218)
Retained earnings	1,912	1,728
Total equity attributable to common stockholders	10,597	10,404
Noncontrolling interests in consolidating subsidiaries	5	7
Total equity	10,602	10,411
Commitments and contingencies
Liabilities and Equity, Total	$ 16,271	$ 16,459

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
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	173,782,802	173,221,845
Treasury Stock, Shares	3,685,802	3,497,742

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues and other income:
Oil and gas	$ 768,000	$ 613,000	$ 1,577,000	$ 1,022,000
Sales of purchased oil and gas	517,000	395,000	1,001,000	618,000
Interest and other	16,000	6,000	30,000	13,000
Derivative gains, net	135,000	(229,000)	286,000	(186,000)
Gain (loss) on disposition of assets, net	194,000	1,000	205,000	3,000
Total revenues and other income	1,630,000	786,000	3,099,000	1,470,000
Costs and expenses:
Oil and gas production	147,000	141,000	288,000	297,000
Production and ad valorem taxes	51,000	36,000	99,000	65,000
Depletion, depreciation and amortization	341,000	384,000	678,000	737,000
Purchased oil and gas	531,000	410,000	1,034,000	653,000
Impairment of oil and gas properties	0	0	285,000	32,000
Exploration and abandonments	26,000	18,000	59,000	77,000
General and administrative	81,000	80,000	165,000	154,000
Accretion of discount on asset retirement obligations	5,000	5,000	10,000	9,000
Interest	35,000	56,000	81,000	111,000
Other	59,000	67,000	119,000	154,000
Costs and Expenses	1,276,000	1,197,000	2,818,000	2,289,000
Income (loss) from continuing operations before income taxes	354,000	(411,000)	281,000	(819,000)
Income tax provision	$ (121,000)	143,000	$ (90,000)	284,000
Net income (loss) attributable to common stockholders		$ (268,000)		$ (535,000)
Basic earnings per share:
Basic and diluted net loss per share attributable to common stockholders	$ 1.36	$ (1.63)	$ 1.11	$ (3.28)
Weighted average shares outstanding:
Basic weighted average shares outstanding	170	164	170	163
Diluted	170	164	170	163
Dividends declared per share	$ 0	$ 0	$ 0.04	$ 0.04
Retained Earnings [Member]
Costs and expenses:
Net income (loss) attributable to common stockholders	$ 233,000		$ 191,000

Consolidated Statement Of Equit

Consolidated Statement Of Equity - 6 months ended Jun. 30, 2017 - USD ($) shares in Thousands, $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]
Beginning Balance, shares at Dec. 31, 2016		169,724
Beginning Balance at Dec. 31, 2016	$ 10,411	$ 2	$ 8,892	$ (218)	$ 1,728	$ 7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared ($0.04 per share)	(7)				(7)
Treasury stock purchases, shares		(188)
Treasury stock purchases	(36)			(36)
Compensation costs:
Vested compensation awards, shares		561
Vested compensation awards	0	$ 0	0
Compensation costs included in net income	43		43			0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	0		2			(2)
Net Income (Loss) Attributable to Parent					191
Net loss	191					0
Ending Balance, shares at Jun. 30, 2017		170,097
Ending Balance at Jun. 30, 2017	$ 10,602	$ 2	$ 8,937	$ (254)	$ 1,912	$ 5

Consolidated Statement Of Equi6

Consolidated Statement Of Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per share	$ 0	$ 0	$ 0.04	$ 0.04

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ 191,000	$ (535,000)
Adjustments to reconcile net income to net cash provided by operating activities:
Depletion, depreciation and amortization	678,000	737,000
Impairment of oil and gas properties	285,000	32,000
Impairment of Inventory and Other Property and Equipment	1,000	5,000
Exploration expenses, including dry holes	18,000	40,000
Deferred income taxes	90,000	(284,000)
Gain on disposition of assets, net	(205,000)	(3,000)
Accretion of discount on asset retirement obligations	10,000	9,000
Interest expense	2,000	9,000
Derivative related activity	(251,000)	535,000
Amortization of stock-based compensation	43,000	44,000
Other	34,000	34,000
Change in operating assets and liabilities, net of effects from acquisitions and dispositions:
Accounts receivable, net	27,000	(51,000)
Income taxes receivable	2,000	39,000
Inventories	(11,000)	(12,000)
Derivatives	0	(12,000)
Increase Decrease in Investments	3,000	0
Other current assets	1,000	0
Accounts payable	(42,000)	(60,000)
Interest payable	(9,000)	20,000
Income taxes payable	0	(2,000)
Other current liabilities	(24,000)	(26,000)
Net cash provided by operating activities	843,000	519,000
Cash flows from investing activities:
Proceeds from disposition of assets, net of cash sold	345,000	2,000
Proceeds from Sale and Maturity of Held-to-maturity Securities	878,000	1,000
Purchase of investment securities	(746,000)	(1,495,000)
Additions to oil and gas properties	(1,074,000)	(971,000)
Additions to other assets and other property and equipment, net	(176,000)	(126,000)
Net cash used in investing activities	(773,000)	(2,589,000)
Cash flows from financing activities:
Principal payments on long-term debt	(485,000)	0
Proceeds from issuance of common stock, net of issuance costs	0	2,534,000
Purchases of treasury stock	(36,000)	(23,000)
Dividends paid	(7,000)	(7,000)
Net cash provided by (used in) financing activities	(528,000)	2,504,000
Net increase (decrease) in cash and cash equivalents	(458,000)	434,000
Cash and cash equivalents, beginning of period	1,118,000	1,391,000
Cash and cash equivalents, end of period	$ 660,000	$ 1,825,000

Organization And Nature Of Oper

Organization And Nature Of Operations	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization And Nature Of Operations	Organization and Nature of Operations Pioneer Natural Resources Company ("Pioneer" or the "Company") is a Delaware corporation whose common stock is listed and traded on the New York Stock Exchange. The Company is a large independent oil and gas exploration and production company that explores for, develops and produces oil, natural gas liquids ("NGLs") and gas within 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 southeast Colorado and the West Panhandle field in the Texas Panhandle.

Basis Of Presentation

Basis Of Presentation	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis Of Presentation	Basis of Presentation Presentation. In the opinion of management, the consolidated financial statements of the Company as of June 30, 2017 and for the three and six months ended June 30, 2017 and 2016 include all adjustments and accruals, consisting only of normal, recurring accrual adjustments, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States ("GAAP") have been condensed in or omitted from this report pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). These consolidated financial statements should be read together with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 . Certain reclassifications have been made to the 2016 financial statement and footnote amounts in order to conform to the 2017 presentation. Issuance of common stock. During the first and second quarters of 2016, the Company issued 13.8 million and 6.0 million shares of common stock, respectively, and received cash proceeds of $1.6 billion and $937 million , respectively, net of associated underwriter discounts and offering expenses. New accounting pronouncements. In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-09, "Improvements to Employee Share-Based Payment Accounting." ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as certain classification changes in the statement of cash flows. The Company adopted this standard on January 1, 2017. See Note M for discussion on the impact of the adoption to the Company's income tax provision. In February 2016, the FASB issued ASU 2016-02, "Leases." ASU 2016-02 requires the recognition of lease assets and lease liabilities by lessees for those leases currently classified as operating leases and makes certain changes to the way lease expenses are accounted for. This update is effective for fiscal years beginning after December 15, 2018 and for interim periods beginning the following year. This update should be applied using a modified retrospective approach, and early adoption is permitted. The Company anticipates that the adoption of ASU 2016-02 for its leasing arrangements will likely (i) increase the Company's recorded assets and liabilities, (ii) increase depreciation, depletion and amortization expense, (iii) increase interest expense and (iv) decrease lease/rental expense. The Company is currently evaluating each of its lease arrangements and has not determined the aggregate amount of change expected for each category. 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. In August 2015, the FASB issued ASU 2015-14, which defers the effective date of ASU 2014-09 for one year to fiscal years beginning after December 15, 2017. Early adoption is permitted for fiscal years beginning after December 15, 2016. In May 2016, the FASB issued ASU 2016-11, which rescinded guidance from the SEC on accounting for gas balancing arrangements and will eliminate the use of the entitlements method. Entities have the option of using either a full retrospective or modified approach to adopt these new standards. The Company plans to utilize the modified approach to adopt the new standards upon their effective dates. The Company is evaluating the new guidance, including identifying revenue streams and reviewing contracts and procedures currently in place. The Company does not anticipate this standard will have a material impact on its consolidated financial statements.

Acquisitions and Divestitures

Acquisitions and Divestitures	6 Months Ended
	Jun. 30, 2017
Acquisitions and Divestitures [Abstract]
Acquisition and Divestitures	Acquisitions and Divestitures Permian Basin Acquisition. In August 2016, the Company acquired approximately 28,000 net acres in the Permian Basin, with net production of approximately 1,400 barrels of oil equivalent per day ("BOEPD"), from an unaffiliated third party for $428 million , including normal closing adjustments. The acquisition was accounted for using the acquisition method under ASC 805, "Business Combinations," which requires acquired assets and liabilities to be recorded at fair value as of the acquisition date. The following table represents the allocation of the acquisition price to the assets acquired and the liabilities assumed based on their fair value at the acquisition date (in millions): Assets acquired: Proved properties $ 79 Unproved properties 347 Other property and equipment 5 Liabilities assumed: Asset retirement obligations (2 ) Other liabilities (1 ) Net assets acquired $ 428 The fair value measurements of the net assets acquired are based on inputs that are not observable in the market and, therefore, represent Level 3 inputs in the fair value hierarchy (see Note D for a description of the input levels in the fair value hierarchy). The Company calculated the fair values of the acquired proved properties and asset retirement obligations using a discounted future cash flow model that utilizes management's estimates of (i) proved reserves, (ii) forecasted production rates, (iii) future operating, development and plugging and abandonment costs, (iv) future commodity prices and (v) a discount rate of 10 percent for proved properties and seven percent for asset retirement obligations. The Company calculated the fair values of the acquired unproved properties based on the average price per acre in comparable market transactions. The operating results attributable to the acquired assets and liabilities assumed are included in the Company's accompanying consolidated statements of operations since the date of acquisition. Divestitures. For the three and six months ended June 30, 2017 , the Company recorded net gains on the disposition of assets of $194 million and $205 million , respectively. For the three and six months ended June 30, 2016 , the Company recorded net gains on the disposition of assets of $1 million and $3 million , respectively. In April 2017, the Company completed the sale of approximately 20,500 acres in the Martin County region of the Permian Basin, with net production of approximately 1,500 BOEPD, to an unaffiliated third party for cash proceeds of $266 million , before normal closing adjustments. The sale resulted in a gain of $194 million . During the three months ended June 30, 2017, the Company reduced the carrying value of goodwill by $2 million , reflecting the portion of the Company's goodwill related to the assets sold. During the six months ended June 30, 2017, the Company also completed the sales of other nonstrategic proved and unproved properties in the Permian Basin for cash proceeds of $77 million , which resulted in a gain of $10 million .

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or the price paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements are based upon inputs that market participants use in pricing an asset or liability, which are characterized according to a hierarchy that prioritizes those inputs based on the degree to which they are observable. Observable inputs represent market data obtained from independent sources, whereas unobservable inputs reflect a company's own market assumptions, which are used if observable inputs are not reasonably available without undue cost and effort. The three input levels of the fair value hierarchy are as follows: • Level 1 – quoted prices for identical assets or liabilities in active markets. • Level 2 – quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates) and inputs derived principally from or corroborated by observable market data by correlation or other means. • Level 3 – unobservable inputs for the asset or liability. Assets and liabilities measured at fair value on a recurring basis. The fair value input hierarchy level to which an asset or liability measurement in its entirety falls is determined based on the lowest level input that is significant to the measurement in its entirety. The following table presents the Company's assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2017 and December 31, 2016 for each of the fair value hierarchy levels: Fair Value Measurement as of June 30, 2017 Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value as of June 30, 2017 (in millions) Assets: Commodity derivatives $ — $ 180 $ — $ 180 Interest rate derivatives — 5 — 5 Deferred compensation plan assets 87 — — 87 Total assets 87 185 — 272 Liabilities: Commodity derivatives — 3 — 3 Diesel derivatives — 1 — 1 Total liabilities — 4 — 4 Total recurring fair value measurements $ 87 $ 181 $ — $ 268 Fair Value Measurement as of December 31, 2016 Using Quoted Prices Significant Significant Fair value as of December 31, 2016 (in millions) Assets: Commodity derivatives $ — $ 8 $ — $ 8 Interest rate derivatives — 6 — 6 Deferred compensation plan assets 83 — — 83 Total assets 83 14 — 97 Liabilities: Commodity derivatives — 84 — 84 Total liabilities — 84 — 84 Total recurring fair value measurements $ 83 $ (70 ) $ — $ 13 Commodity and diesel derivatives. The Company's commodity derivatives represent oil, NGL and gas swap contracts, collar contracts and collar contracts with short puts. The Company's diesel derivative liability represents swap contracts. The asset and liability measurements for these derivative contracts represent Level 2 inputs in the hierarchy. The Company utilizes discounted cash flow and option-pricing models for valuing its commodity and diesel derivatives. The asset and liability values attributable to the Company's commodity and diesel derivatives were determined based on inputs that include (i) the contracted notional volumes, (ii) independent active market price quotes, (iii) the applicable estimated credit-adjusted risk-free rate yield curve and (iv) the implied rate of volatility inherent in the collar contracts 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 June 30, 2017 , the significant inputs to these asset values represented Level 1 independent active exchange market price inputs. Interest rate derivatives. The Company's interest rate derivative assets represent interest rate swap contracts. The Company utilizes discounted cash flow models for valuing its interest rate derivatives. The derivative values attributable to the Company's interest rate derivative contracts are based on (i) the contracted notional amounts, (ii) forward active market-quoted London Interbank Offered Rates ("LIBOR") and (iii) the applicable credit-adjusted risk-free rate yield curve. The Company's interest rate derivative fair value measurements represent Level 2 inputs in the hierarchy. 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 or liabilities that are acquired or written down to fair value when they are impaired or held for sale. See Note C for information on the fair value of assets and liabilities acquired in the Permian Basin acquisition. Proved oil and gas properties . As a result of the Company's proved property impairment assessments, the Company recognized noncash impairment charges to reduce the carrying values of (i) the Raton field during the three months ended March 31, 2017 and (ii) the West Panhandle field during the three months ended March 31, 2016 to their estimated fair values. The Company calculated the fair values of the Raton and West Panhandle fields using a discounted future cash flow model. Significant Level 3 assumptions associated with the calculations included management's longer-term commodity price outlooks ("Management's Price Outlooks") and management's outlooks for (i) production, (ii) production costs, (iii) capital expenditures 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 2017 and 2016 proved property impairments, as well as the average oil price per barrel ("Bbl") and gas price per British thermal unit ("MMBtu") utilized in the respective Management's Price Outlooks: Management's Price Outlooks Impairment Date Fair Value Fair Value Adjustment Oil Gas Raton March 2017 $ 186 $ (285 ) $ 53.65 $ 3.00 West Panhandle March 2016 $ 33 $ (32 ) $ 49.77 $ 3.24 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 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 reserves. Unproved oil and gas properties. During March 2016, the Company recorded an impairment charge of $32 million to write-off the carrying value of its unproved royalty acreage in Alaska (reported in exploration and abandonments in the accompanying consolidated statements of operations) as a result of the operator curtailing operations in the area and Management's Price Outlooks. Financial instruments not carried at fair value. Carrying values and fair values of financial instruments that are not carried at fair value in the accompanying consolidated balance sheets as of June 30, 2017 and December 31, 2016 are as follows: June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value (in millions) Commercial paper, corporate bonds and time deposits $ 1,726 $ 1,723 $ 1,906 $ 1,901 Current portion of long-term debt $ 449 $ 468 $ 485 $ 490 Long-term debt $ 2,281 $ 2,490 $ 2,728 $ 2,956 Commercial paper, corporate bonds and time deposits. Periodically, the Company invests in commercial paper and corporate bonds with investment grade rated entities. The Company also periodically enters into time deposits with financial institutions. The investments are carried at amortized cost and classified as held-to-maturity as the Company has the intent and ability to hold them until they mature. The carrying values of held-to-maturity investments are adjusted for amortization of premiums and accretion of discounts over the remaining life of the investment. Income related to these investments is recorded in interest and other income in the Company's consolidated statements of operations. The Company's investments in corporate bonds represent Level 1 inputs in the hierarchy, while other investments represent Level 2 inputs in the hierarchy. Commercial paper and time deposits are included in cash and cash equivalents if they have maturity dates that are less than 90 days at the date of purchase; otherwise, investments are reflected in short-term investments or long-term investments in the accompanying consolidated balance sheets based on their maturity dates. The following table provides the components of the Company's cash and cash equivalents and investments as of June 30, 2017 and December 31, 2016 : June 30, 2017 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Deposits Total (in millions) Cash and cash equivalents $ 560 $ — $ — $ 100 $ 660 Short-term investments — 138 865 536 1,539 Long-term investments — — 187 — 187 $ 560 $ 138 $ 1,052 $ 636 $ 2,386 December 31, 2016 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Total (in millions) Cash and cash equivalents $ 873 $ 45 $ — $ 200 $ 1,118 Short-term investments — 368 691 382 1,441 Long-term investments — — 420 — 420 $ 873 $ 413 $ 1,111 $ 582 $ 2,979 Debt obligations. The Company's debt obligations are composed of its credit facility and senior notes. The fair value of the Company's debt obligations is determined utilizing inputs that are Level 2 measurements in the fair value hierarchy. The fair value 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. 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 receivables, 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.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company utilizes commodity swap contracts, collar contracts and collar contracts with short puts to (i) reduce the effect of price volatility on the commodities the Company produces and sells or consumes, (ii) support the Company's annual capital budgeting and expenditure plans and (iii) reduce commodity price risk associated with certain capital projects. The Company also, from time to time, utilizes interest rate contracts to reduce the effect of interest rate volatility on the Company's indebtedness. Periodically, the Company may pay a premium to enter into commodity contracts. Premiums paid, if any, have been nominal in relation to the value of the underlying asset in the contract. The Company recognizes the nominal premium payments as an increase to the value of derivative assets when paid. All derivatives are adjusted to fair value as of each balance sheet date. 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 the 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 June 30, 2017 and the weighted average oil prices for those contracts: 2017 Year Ending December 31, 2018 Third Quarter Fourth Quarter Collar contracts: Volume (Bbl) 6,000 6,000 — Price per Bbl: Ceiling $ 70.40 $ 70.40 $ — Floor $ 50.00 $ 50.00 $ — Collar contracts with short puts (a): Volume (Bbl) 147,000 155,000 71,000 Price per Bbl: Ceiling $ 62.03 $ 62.12 $ 60.38 Floor $ 49.81 $ 49.82 $ 50.07 Short put $ 41.07 $ 41.02 $ 40.00 ____________________ (a) Subsequent to June 30, 2017 , the Company entered into additional oil collar contracts with short puts for 26,000 Bbl per day of 2018 production with a ceiling price of $55.01 per Bbl, a floor price of $45.00 per Bbl and a short put price of $35.00 per Bbl. NGL production derivative activities. All material physical sales contracts governing the Company's NGL production are tied directly or indirectly to either Mont Belvieu, Texas or Conway, Kansas NGL component product prices. The Company uses derivative contracts to manage NGL component price volatility. The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of June 30, 2017 and the weighted average NGL prices for those contracts: 2017 Year Ending December 31, Third Quarter Fourth Quarter 2018 2019 Butane collar contracts with short puts (a): Volume (Bbl) 2,000 — — — Price per Bbl: Ceiling $ 36.12 $ — $ — $ — Floor $ 29.25 $ — $ — $ — Short put $ 23.40 $ — $ — $ — Ethane collar contracts (b): Volume (Bbl) 3,000 3,000 — — Price per Bbl: Ceiling $ 11.83 $ 11.83 $ — $ — Floor $ 8.68 $ 8.68 $ — $ — Ethane basis swap contracts (c): Volume (MMBtu) 6,920 6,920 6,920 6,920 Price differential ($/MMBtu) $ 1.60 $ 1.60 $ 1.60 $ 1.60 ____________________ (a) Represent collar contracts with short puts that reduce the price volatility of butane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. (b) Represent collar contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. (c) Represent basis swap contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. The basis swap contracts fix the basis differential on a NYMEX Henry Hub ("HH") MMBtu equivalent basis. The Company will receive the HH price plus the price differential on 6,920 MMBtu per day, which is equivalent to 2,500 Bbls per day of ethane. Gas production derivative activities. All material physical sales contracts governing the Company's gas production are tied directly or indirectly to 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 June 30, 2017 and the weighted average gas prices for those contracts: 2017 Year Ending December 31, 2018 Third Quarter Fourth Quarter Collar contracts with short puts: Volume (MMBtu) 290,000 300,000 62,329 Price per MMBtu: Ceiling $ 3.57 $ 3.60 $ 3.56 Floor $ 2.95 $ 2.96 $ 2.91 Short put $ 2.47 $ 2.47 $ 2.37 Basis swap contracts: Mid-Continent index swap volume (MMBtu) (a) 45,000 45,000 — Price differential ($/MMBtu) $ (0.32 ) $ (0.32 ) $ — Permian Basin index swap volume (MMBtu) (b) — 26,522 39,945 Price differential ($/MMBtu) $ — $ 0.30 $ 0.30 ____________________ (a) Represent swap contracts that fix the basis differentials between the index price at which the Company sells its Mid-Continent gas and the HH index price used in collar contracts with short puts. (b) Represent swap contracts that fix the basis differentials between Permian Basin index prices and southern California index prices for Permian Basin gas forecasted for sale in southern California. Subsequent to June 30, 2017 , the Company entered into additional basis swap contracts for 6,739 MMBtu per day of third quarter 2017 production with a price of $0.26 per MMBtu and 11,726 MMBtu per day of 2018 production with a price differential of $0.31 per MMBtu. Diesel derivative activities. Periodically, the Company enters into diesel derivative swap contracts to mitigate fuel price risk. The diesel derivative swap contracts are priced at an index that is highly correlated to the prices that the Company incurs to fuel drilling rigs and its fracture stimulation fleet equipment. As of June 30, 2017 , the Company was party to diesel derivative swap contracts for 1,000 Bbls per day for the remainder of 2017 at an average per Bbl fixed price of $63.00 . Subsequent to June 30, 2017 , the Company terminated its diesel derivative swap contracts for August through December 2017 for cash proceeds of $321 thousand . Interest rate derivative activities. As of June 30, 2017 , the Company was party to interest rate derivative contracts whereby the Company will receive the three-month LIBOR rate for the 10-year period from December 2017 through December 2027 in exchange for paying a fixed interest rate of 1.81 percent on a notional amount of $100 million on December 15, 2017. Tabular disclosure of derivative financial instruments . All of the Company's derivatives are accounted for as non-hedge derivatives as of June 30, 2017 and December 31, 2016 , 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 accompanying 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 June 30, 2017 Type Consolidated Balance Sheet Location Fair Value Gross Amounts Offset in the Consolidated Balance Sheet Net Fair Value Presented in the Consolidated Balance Sheet (in millions) Derivatives not designated as hedging instruments Asset Derivatives: Commodity price derivatives Derivatives - current $ 153 $ (2 ) $ 151 Interest rate derivatives Derivatives - current $ 5 $ — 5 Commodity price derivatives Derivatives - noncurrent $ 30 $ (1 ) 29 $ 185 Liability Derivatives: Commodity and diesel price derivatives Derivatives - current $ 5 $ (2 ) $ 3 Commodity price derivatives Derivatives - noncurrent $ 2 $ (1 ) 1 $ 4 Fair Value of Derivative Instruments as of December 31, 2016 Type Consolidated Balance Sheet Location Fair Value Gross Amounts Offset in the Consolidated Balance Sheet Net Fair Value Presented in the Consolidated Balance Sheet (in millions) Derivatives not designated as hedging instruments Asset Derivatives: Commodity price derivatives Derivatives - current $ 33 $ (25 ) $ 8 Interest rate derivatives Derivatives - current $ 6 $ — 6 $ 14 Liability Derivatives: Commodity price derivatives Derivatives - current $ 102 $ (25 ) $ 77 Commodity price derivatives Derivatives - noncurrent $ 7 $ — 7 $ 84 The Company uses credit and other financial criteria to evaluate the credit standing of, and to select, counterparties to its derivative instruments. Although the Company does not obtain collateral or otherwise secure the fair value of its derivative instruments, associated credit risk is mitigated by the Company's credit risk policies and procedures. The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations: Derivatives Not Designated as Location of Gain / (Loss) Recognized in Three Months Ended Six Months Ended Hedging Instruments Earnings on Derivatives 2017 2016 2017 2016 (in millions) Commodity price derivatives Derivative gains (losses), net $ 136 $ (222 ) $ 287 $ (177 ) Interest rate derivatives Derivative gains (losses), net (1 ) (7 ) (1 ) (9 ) Total $ 135 $ (229 ) $ 286 $ (186 )

Exploratory Costs

Exploratory Costs	6 Months Ended
	Jun. 30, 2017
Exploratory Cost Disclosure [Abstract]
Exploratory Costs	Exploratory Costs The Company capitalizes exploratory well and project costs until a determination is made that the well or project has either found proved reserves, is impaired or is sold. The Company's capitalized exploratory well and project costs are presented in proved properties in the accompanying consolidated balance sheets. If the exploratory well or project is determined to be impaired, the impaired costs are charged to exploration and abandonments expense. The following table reflects the Company's capitalized exploratory well and project activity during the three and six months ended June 30, 2017 : Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 (in millions) Beginning capitalized exploratory well costs $ 432 $ 323 Additions to exploratory well costs pending the determination of proved reserves 489 895 Reclassification due to determination of proved reserves (477 ) (765 ) Exploratory well costs charged to exploration and abandonment expense (1 ) (10 ) Ending capitalized exploratory well costs $ 443 $ 443 The following table provides an aging as of June 30, 2017 and December 31, 2016 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: June 30, 2017 December 31, 2016 (in millions, except well counts) Capitalized exploratory well costs that have been suspended: One year or less $ 420 $ 318 More than one year 23 5 $ 443 $ 323 Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year 12 3 The 12 wells that were suspended for a period greater than one year as of June 30, 2017 are in the Eagle Ford Shale area. The Company expects to complete five of these wells in 2017 and the remaining seven wells in 2018.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Long-Term Debt	Long-term Debt Credit facility. The Company's long-term debt consists of senior notes, a revolving corporate credit facility (the "Credit Facility") and the effects of issuance costs and discounts. The Credit Facility is maintained with a syndicate of financial institutions and has aggregate loan commitments of $1.5 billion that expire in August 2020. As of June 30, 2017 , the Company had no outstanding borrowings under the Credit Facility and was in compliance with its debt covenants. Senior notes. The Company's 6.65% senior notes (the "6.65% Senior Notes") matured and were repaid in March 2017. The Company funded the $485 million repayment of the 6.65% Senior Notes with cash on hand. The Company's 6.875% senior notes (the "6.875% Senior Notes"), with an outstanding debt principal balance of $450 million , will mature in May 2018. The 6.875% Senior Notes are classified as current in the accompanying consolidated balance sheets as of June 30, 2017.

Incentive Plans

Incentive Plans	6 Months Ended
	Jun. 30, 2017
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Incentive Plans	Incentive Plans Stock-based compensation. For the three and six months ended June 30, 2017 , the Company recorded $27 million and $57 million , respectively, of stock-based compensation expense for all plans, as compared to $29 million and $53 million for the same respective periods in 2016 . As of June 30, 2017 , there was $137 million of unrecognized stock-based compensation expense related to unvested share-based compensation plans, including $31 million attributable to stock-based awards that are expected to be settled on their vesting date in cash, rather than in equity shares ("Liability Awards"). The unrecognized 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. As of June 30, 2017 and December 31, 2016 , accounts payable – due to affiliates included $10 million and $22 million , respectively, of liabilities attributable to Liability Awards. The following table summarizes the activity that occurred during the six months ended June 30, 2017 for each type of share-based incentive award issued by Pioneer: Restricted Stock Equity Awards Restricted Stock Liability Awards Performance Units Stock Options Outstanding as of December 31, 2016 1,077,227 290,552 178,556 159,378 Awards granted 320,103 108,911 59,044 — Awards forfeited (13,527 ) (5,012 ) — — Awards vested (437,845 ) (129,499 ) — — Outstanding as of June 30, 2017 945,958 264,952 237,600 159,378

Asset Retirement Obligations

Asset Retirement Obligations	6 Months Ended
	Jun. 30, 2017
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The Company's asset retirement obligations primarily relate to the future plugging and abandonment of wells and related facilities. The following table summarizes the Company's asset retirement obligation activity during the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Beginning asset retirement obligations $ 297 $ 285 $ 297 $ 285 New wells placed on production 1 — 1 — Changes in estimates 7 — 7 — Dispositions (7 ) — (7 ) — Liabilities settled (9 ) (9 ) (14 ) (13 ) Accretion of discount 5 5 10 9 Ending asset retirement obligations $ 294 $ 281 $ 294 $ 281 The Company records the current and noncurrent portions of asset retirement obligations in other current liabilities and other liabilities, respectively, in the accompanying consolidated balance sheets. As of June 30, 2017 and December 31, 2016, the current portion of the Company's asset retirement obligations was $46 million and $39 million , respectively.

Commitments And Contingencies

Commitments And Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies In addition to the legal action described below, the Company is a party to other proceedings and claims incidental to its business. While many of these matters involve inherent uncertainty, the Company believes that the amount of the liability, if any, ultimately incurred with respect to such proceedings and claims will not have a material adverse effect on the Company's 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. U.S. Environmental Protection Agency ("EPA") potential enforcement action. The Company has been advised by the EPA that the agency is considering an enforcement action against the Company and may seek monetary sanctions for alleged failures to prevent emissions occurring at the Company's Fain gas plant in the West Panhandle region of Texas on five separate occasions. The Company has asserted defenses to the EPA's allegations and is in discussions with the EPA regarding these matters. Although the Company cannot predict the outcome of these discussions with any certainty, the Company believes such monetary sanctions will not exceed $45,000 for any single event, but could exceed $100,000 in the aggregate. 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. The Company does not believe these obligations are probable of having a material impact on its liquidity, financial position or future results of operations. Lease agreements. In June 2017, the Company entered into a 20-year operating lease for the Company's new corporate headquarters in Irving, TX. Annual base rent will be $33 million and lease payments are expected to commence in the second half of 2019 when the building is complete.

Interest And Other Income

Interest And Other Income	6 Months Ended
	Jun. 30, 2017
Interest and Other Income [Abstract]
Interest And Other Income	Interest and Other Income The following table provides the components of the Company's interest and other income for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Interest income $ 10 $ 5 $ 16 $ 9 Severance and sales tax refunds 5 — 8 — Deferred compensation plan income 1 — 3 2 Other income — 1 3 2 Total interest and other income $ 16 $ 6 $ 30 $ 13

Other Expense

Other Expense	6 Months Ended
	Jun. 30, 2017
Other Expense [Abstract]
Other Expense	Other Expense The following table provides the components of the Company's other expense for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Transportation commitment charges (a) $ 43 $ 25 $ 82 $ 50 Loss from vertical integration services (b) 5 16 11 29 Idle drilling and well service equipment charges (c) — 11 — 47 Other 11 15 26 28 Total other expense $ 59 $ 67 $ 119 $ 154 ____________________ (a) Primarily represents firm transportation payments on excess pipeline capacity commitments. (b) Loss from vertical integration services primarily represents net margins (attributable to third party working interest owners) that result from Company-provided fracture stimulation and well service operations, which are ancillary to and supportive of the Company's oil and gas joint operating activities, and do not represent intercompany transactions. For the three and six months ended June 30, 2017 , these vertical integration net margins included $23 million and $42 million , respectively, of revenues and $28 million and $53 million , respectively, of costs and expenses. For the same respective periods in 2016, these vertical integration net margins included $56 million and $124 million of revenues and $72 million and $153 million of costs and expenses. (c) Primarily represents expenses attributable to idle drilling rig fees that are not chargeable to joint operations and charges to terminate rig contracts that were not required to meet planned drilling activities.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's income tax benefit (provision) consisted of the following for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Deferred tax benefit (provision) $ (121 ) $ 143 (90 ) 284 For the three and six months ended June 30, 2017 , the Company's effective tax rate, excluding income attributable to noncontrolling interests, was 34 percent and 32 percent , respectively, as compared to an effective rate of 35 percent for both of the same respective periods in 2016 . The Company's effective tax rate for the six months ended June 30, 2017 differs from the U.S. statutory rate of 35 percent primarily due to recognizing excess tax benefits of $8 million associated with the adoption of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting," which requires excess tax benefits or deficiencies associated with the vesting of long-term incentive awards to be recorded as income tax expense or benefit in the statement of operations rather than as an adjustment to additional paid-in capital in the balance sheet. 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. As of June 30, 2017 and December 31, 2016 , the Company had unrecognized tax benefits of $119 million and $112 million , respectively, resulting from research and experimental expenditures related to horizontal drilling and completions innovations. If all or a portion of the unrecognized tax benefit is sustained upon examination by the taxing authorities, the tax benefit will be recognized as a reduction to the Company's deferred tax liability and will affect the Company's effectiv e ta x rate in the period it is recognized. The Company expects to resolve the uncertainties associated with the unrecognized tax benefit by December 2018 . The Company files income tax returns in the U.S. federal and various state and foreign jurisdictions. The Internal Revenue Service has closed examinations of the 2012 and prior tax years and, with few exceptions, the Company believes that it is no longer subject to examinations by state and foreign tax authorities for years before 2011. As of June 30, 2017 , no adjustments had been proposed in any jurisdiction that would have a significant effect on the Company's liquidity, future results of operations or financial position.

Net Income Per Share

Net Income Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Net Income Per Share	Net Income (Loss) Per Share The following table reconciles the Company's net income (loss) attributable to common stockholders to basic and diluted net income (loss) attributable to common stockholders for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Net income (loss) attributable to common stockholders $ 233 $ (268 ) $ 191 $ (535 ) Participating share-based earnings (2 ) — (2 ) — Basic and diluted net income (loss) attributable to common stockholders $ 231 $ (268 ) $ 189 $ (535 ) Basic and diluted weighted average common shares outstanding were 170 million for the three and six months ended June 30, 2017 , respectively, as compared to 164 million and 163 million for the same respective periods in 2016 .

Basis Of Presentation (Policies

Basis Of Presentation (Policies)	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Presentation	Presentation. In the opinion of management, the consolidated financial statements of the Company as of June 30, 2017 and for the three and six months ended June 30, 2017 and 2016 include all adjustments and accruals, consisting only of normal, recurring accrual adjustments, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States ("GAAP") have been condensed in or omitted from this report pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). These consolidated financial statements should be read together with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 . Certain reclassifications have been made to the 2016 financial statement and footnote amounts in order to conform to the 2017 presentation.
New Accounting Pronouncements, Policy [Policy Text Block]	New accounting pronouncements. In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-09, "Improvements to Employee Share-Based Payment Accounting." ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as certain classification changes in the statement of cash flows. The Company adopted this standard on January 1, 2017. See Note M for discussion on the impact of the adoption to the Company's income tax provision. In February 2016, the FASB issued ASU 2016-02, "Leases." ASU 2016-02 requires the recognition of lease assets and lease liabilities by lessees for those leases currently classified as operating leases and makes certain changes to the way lease expenses are accounted for. This update is effective for fiscal years beginning after December 15, 2018 and for interim periods beginning the following year. This update should be applied using a modified retrospective approach, and early adoption is permitted. The Company anticipates that the adoption of ASU 2016-02 for its leasing arrangements will likely (i) increase the Company's recorded assets and liabilities, (ii) increase depreciation, depletion and amortization expense, (iii) increase interest expense and (iv) decrease lease/rental expense. The Company is currently evaluating each of its lease arrangements and has not determined the aggregate amount of change expected for each category. 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. In August 2015, the FASB issued ASU 2015-14, which defers the effective date of ASU 2014-09 for one year to fiscal years beginning after December 15, 2017. Early adoption is permitted for fiscal years beginning after December 15, 2016. In May 2016, the FASB issued ASU 2016-11, which rescinded guidance from the SEC on accounting for gas balancing arrangements and will eliminate the use of the entitlements method. Entities have the option of using either a full retrospective or modified approach to adopt these new standards. The Company plans to utilize the modified approach to adopt the new standards upon their effective dates. The Company is evaluating the new guidance, including identifying revenue streams and reviewing contracts and procedures currently in place. The Company does not anticipate this standard will have a material impact on its consolidated financial statements.

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	6 Months Ended
	Jun. 30, 2017
Acquisitions and Divestitures [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table represents the allocation of the acquisition price to the assets acquired and the liabilities assumed based on their fair value at the acquisition date (in millions): Assets acquired: Proved properties $ 79 Unproved properties 347 Other property and equipment 5 Liabilities assumed: Asset retirement obligations (2 ) Other liabilities (1 ) Net assets acquired $ 428

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis	The following table presents the Company's assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2017 and December 31, 2016 for each of the fair value hierarchy levels: Fair Value Measurement as of June 30, 2017 Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value as of June 30, 2017 (in millions) Assets: Commodity derivatives $ — $ 180 $ — $ 180 Interest rate derivatives — 5 — 5 Deferred compensation plan assets 87 — — 87 Total assets 87 185 — 272 Liabilities: Commodity derivatives — 3 — 3 Diesel derivatives — 1 — 1 Total liabilities — 4 — 4 Total recurring fair value measurements $ 87 $ 181 $ — $ 268 Fair Value Measurement as of December 31, 2016 Using Quoted Prices Significant Significant Fair value as of December 31, 2016 (in millions) Assets: Commodity derivatives $ — $ 8 $ — $ 8 Interest rate derivatives — 6 — 6 Deferred compensation plan assets 83 — — 83 Total assets 83 14 — 97 Liabilities: Commodity derivatives — 84 — 84 Total liabilities — 84 — 84 Total recurring fair value measurements $ 83 $ (70 ) $ — $ 13
Fair Value Measurements, Nonrecurring [Table Text Block]	The following table presents the fair value and fair value adjustments (in millions) for the Company's 2017 and 2016 proved property impairments, as well as the average oil price per barrel ("Bbl") and gas price per British thermal unit ("MMBtu") utilized in the respective Management's Price Outlooks: Management's Price Outlooks Impairment Date Fair Value Fair Value Adjustment Oil Gas Raton March 2017 $ 186 $ (285 ) $ 53.65 $ 3.00 West Panhandle March 2016 $ 33 $ (32 ) $ 49.77 $ 3.24
Schedule of carrying values and financial instruments not carried at fair value	Carrying values and fair values of financial instruments that are not carried at fair value in the accompanying consolidated balance sheets as of June 30, 2017 and December 31, 2016 are as follows: June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value (in millions) Commercial paper, corporate bonds and time deposits $ 1,726 $ 1,723 $ 1,906 $ 1,901 Current portion of long-term debt $ 449 $ 468 $ 485 $ 490 Long-term debt $ 2,281 $ 2,490 $ 2,728 $ 2,956
Cash, Cash Equivalents and Investments [Table Text Block]	The following table provides the components of the Company's cash and cash equivalents and investments as of June 30, 2017 and December 31, 2016 : June 30, 2017 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Deposits Total (in millions) Cash and cash equivalents $ 560 $ — $ — $ 100 $ 660 Short-term investments — 138 865 536 1,539 Long-term investments — — 187 — 187 $ 560 $ 138 $ 1,052 $ 636 $ 2,386 December 31, 2016 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Total (in millions) Cash and cash equivalents $ 873 $ 45 $ — $ 200 $ 1,118 Short-term investments — 368 691 382 1,441 Long-term investments — — 420 — 420 $ 873 $ 413 $ 1,111 $ 582 $ 2,979

Derivative Financial Instrume25

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of oil derivative contracts volume and weighted average price	The following table sets forth the volumes per day associated with the Company's outstanding oil derivative contracts as of June 30, 2017 and the weighted average oil prices for those contracts: 2017 Year Ending December 31, 2018 Third Quarter Fourth Quarter Collar contracts: Volume (Bbl) 6,000 6,000 — Price per Bbl: Ceiling $ 70.40 $ 70.40 $ — Floor $ 50.00 $ 50.00 $ — Collar contracts with short puts (a): Volume (Bbl) 147,000 155,000 71,000 Price per Bbl: Ceiling $ 62.03 $ 62.12 $ 60.38 Floor $ 49.81 $ 49.82 $ 50.07 Short put $ 41.07 $ 41.02 $ 40.00 ____________________ (a) Subsequent to June 30, 2017 , the Company entered into additional oil collar contracts with short puts for 26,000 Bbl per day of 2018 production with a ceiling price of $55.01 per Bbl, a floor price of $45.00 per Bbl and a short put price of $35.00 per Bbl.
Schedule of NGL derivative volumes and weighted average prices	The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of June 30, 2017 and the weighted average NGL prices for those contracts: 2017 Year Ending December 31, Third Quarter Fourth Quarter 2018 2019 Butane collar contracts with short puts (a): Volume (Bbl) 2,000 — — — Price per Bbl: Ceiling $ 36.12 $ — $ — $ — Floor $ 29.25 $ — $ — $ — Short put $ 23.40 $ — $ — $ — Ethane collar contracts (b): Volume (Bbl) 3,000 3,000 — — Price per Bbl: Ceiling $ 11.83 $ 11.83 $ — $ — Floor $ 8.68 $ 8.68 $ — $ — Ethane basis swap contracts (c): Volume (MMBtu) 6,920 6,920 6,920 6,920 Price differential ($/MMBtu) $ 1.60 $ 1.60 $ 1.60 $ 1.60 ____________________ (a) Represent collar contracts with short puts that reduce the price volatility of butane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. (b) Represent collar contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. (c) Represent basis swap contracts that reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. The basis swap contracts fix the basis differential on a NYMEX Henry Hub ("HH") MMBtu equivalent basis. The Company will receive the HH price plus the price differential on 6,920 MMBtu per day, which is equivalent to 2,500 Bbls per day of ethane.
Schedule of gas derivative volume and weighted average prices	The following table sets forth the volumes per day associated with the Company's outstanding gas derivative contracts as of June 30, 2017 and the weighted average gas prices for those contracts: 2017 Year Ending December 31, 2018 Third Quarter Fourth Quarter Collar contracts with short puts: Volume (MMBtu) 290,000 300,000 62,329 Price per MMBtu: Ceiling $ 3.57 $ 3.60 $ 3.56 Floor $ 2.95 $ 2.96 $ 2.91 Short put $ 2.47 $ 2.47 $ 2.37 Basis swap contracts: Mid-Continent index swap volume (MMBtu) (a) 45,000 45,000 — Price differential ($/MMBtu) $ (0.32 ) $ (0.32 ) $ — Permian Basin index swap volume (MMBtu) (b) — 26,522 39,945 Price differential ($/MMBtu) $ — $ 0.30 $ 0.30 ____________________ (a) Represent swap contracts that fix the basis differentials between the index price at which the Company sells its Mid-Continent gas and the HH index price used in collar contracts with short puts. (b) Represent swap contracts that fix the basis differentials between Permian Basin index prices and southern California index prices for Permian Basin gas forecasted for sale in southern California.
Offsetting Asset and Liability	The aggregate fair value of the Company's derivative instruments reported in the accompanying 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 June 30, 2017 Type Consolidated Balance Sheet Location Fair Value Gross Amounts Offset in the Consolidated Balance Sheet Net Fair Value Presented in the Consolidated Balance Sheet (in millions) Derivatives not designated as hedging instruments Asset Derivatives: Commodity price derivatives Derivatives - current $ 153 $ (2 ) $ 151 Interest rate derivatives Derivatives - current $ 5 $ — 5 Commodity price derivatives Derivatives - noncurrent $ 30 $ (1 ) 29 $ 185 Liability Derivatives: Commodity and diesel price derivatives Derivatives - current $ 5 $ (2 ) $ 3 Commodity price derivatives Derivatives - noncurrent $ 2 $ (1 ) 1 $ 4
Schedule of derivative gains and losses recognized on statement of operations	The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations: Derivatives Not Designated as Location of Gain / (Loss) Recognized in Three Months Ended Six Months Ended Hedging Instruments Earnings on Derivatives 2017 2016 2017 2016 (in millions) Commodity price derivatives Derivative gains (losses), net $ 136 $ (222 ) $ 287 $ (177 ) Interest rate derivatives Derivative gains (losses), net (1 ) (7 ) (1 ) (9 ) Total $ 135 $ (229 ) $ 286 $ (186 )

Exploratory Costs (Tables)

Exploratory Costs (Tables)	6 Months Ended
	Jun. 30, 2017
Exploratory Cost Disclosure [Abstract]
Capitalized exploratory well and project activity	The following table reflects the Company's capitalized exploratory well and project activity during the three and six months ended June 30, 2017 : Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 (in millions) Beginning capitalized exploratory well costs $ 432 $ 323 Additions to exploratory well costs pending the determination of proved reserves 489 895 Reclassification due to determination of proved reserves (477 ) (765 ) Exploratory well costs charged to exploration and abandonment expense (1 ) (10 ) Ending capitalized exploratory well costs $ 443 $ 443
Capitalized Exploratory Costs And The Number Of Projects For Which Exploratory Costs Have Been Capitalized	The following table provides an aging as of June 30, 2017 and December 31, 2016 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: June 30, 2017 December 31, 2016 (in millions, except well counts) Capitalized exploratory well costs that have been suspended: One year or less $ 420 $ 318 More than one year 23 5 $ 443 $ 323 Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year 12 3

Incentive Plans (Tables)

Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2017
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Schedule of Share Based Incentive Award Activity	The following table summarizes the activity that occurred during the six months ended June 30, 2017 for each type of share-based incentive award issued by Pioneer: Restricted Stock Equity Awards Restricted Stock Liability Awards Performance Units Stock Options Outstanding as of December 31, 2016 1,077,227 290,552 178,556 159,378 Awards granted 320,103 108,911 59,044 — Awards forfeited (13,527 ) (5,012 ) — — Awards vested (437,845 ) (129,499 ) — — Outstanding as of June 30, 2017 945,958 264,952 237,600 159,378

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	6 Months Ended
	Jun. 30, 2017
Asset Retirement Obligation [Abstract]
Schedule of asset retirement obligations	The following table summarizes the Company's asset retirement obligation activity during the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Beginning asset retirement obligations $ 297 $ 285 $ 297 $ 285 New wells placed on production 1 — 1 — Changes in estimates 7 — 7 — Dispositions (7 ) — (7 ) — Liabilities settled (9 ) (9 ) (14 ) (13 ) Accretion of discount 5 5 10 9 Ending asset retirement obligations $ 294 $ 281 $ 294 $ 281

Interest And Other Income (Tabl

Interest And Other Income (Tables)	6 Months Ended
	Jun. 30, 2017
Interest and Other Income [Abstract]
Components of interest and other income	The following table provides the components of the Company's interest and other income for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Interest income $ 10 $ 5 $ 16 $ 9 Severance and sales tax refunds 5 — 8 — Deferred compensation plan income 1 — 3 2 Other income — 1 3 2 Total interest and other income $ 16 $ 6 $ 30 $ 13

Other Expense (Tables)

Other Expense (Tables)	6 Months Ended
	Jun. 30, 2017
Other Expense [Abstract]
Schedule of components of other expense	The following table provides the components of the Company's other expense for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Transportation commitment charges (a) $ 43 $ 25 $ 82 $ 50 Loss from vertical integration services (b) 5 16 11 29 Idle drilling and well service equipment charges (c) — 11 — 47 Other 11 15 26 28 Total other expense $ 59 $ 67 $ 119 $ 154 ____________________ (a) Primarily represents firm transportation payments on excess pipeline capacity commitments. (b) Loss from vertical integration services primarily represents net margins (attributable to third party working interest owners) that result from Company-provided fracture stimulation and well service operations, which are ancillary to and supportive of the Company's oil and gas joint operating activities, and do not represent intercompany transactions. For the three and six months ended June 30, 2017 , these vertical integration net margins included $23 million and $42 million , respectively, of revenues and $28 million and $53 million , respectively, of costs and expenses. For the same respective periods in 2016, these vertical integration net margins included $56 million and $124 million of revenues and $72 million and $153 million of costs and expenses. (c) Primarily represents expenses attributable to idle drilling rig fees that are not chargeable to joint operations and charges to terminate rig contracts that were not required to meet planned drilling activities.

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income tax (provisions) benefits attributable to income from continuing operations	The Company's income tax benefit (provision) consisted of the following for the three and six months ended June 30, 2017 and 2016 : Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Deferred tax benefit (provision) $ (121 ) $ 143 (90 ) 284

Net Income Per Share (Tables)

Net Income Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Reconciliation of earnings attributable to common stockholders, basic and diluted	Three Months Ended Six Months Ended 2017 2016 2017 2016 (in millions) Net income (loss) attributable to common stockholders $ 233 $ (268 ) $ 191 $ (535 ) Participating share-based earnings (2 ) — (2 ) — Basic and diluted net income (loss) attributable to common stockholders $ 231 $ (268 ) $ 189 $ (535 )

Basis Of Presentation Basis of

Basis Of Presentation Basis of Presentation (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016
Summary Of Significant Accounting Policies [Line Items]
Stock Issued During Period, Shares, New Issues	6	13.8
Proceeds from issuance of common stock, net of issuance costs	$ 937	$ 1,600	$ 0	$ 2,534

Acquisitions and Divestitures A

Acquisitions and Divestitures Acquisitions and Divestitures (Business Combination) (Details) - Permian Basin [Member] $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)aBoe
Business Acquisition [Line Items]
Gas and Oil Area, Developed, Net | a	28,000
Production, Barrels of Oil Equivalents | Boe	1,400
Payments to Acquire Businesses, Net of Cash Acquired	$ 428
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	79
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	347
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings	5
AssetRetirementObligationLiabilitiesAcquiredInBusinessCombination	(2)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(1)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 428

Acquisitions and Divestitures35

Acquisitions and Divestitures (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)aBoe	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)a	Jun. 30, 2016USD ($)
Acquisitions and Divestitures [Line Items]
Gain (loss) on disposition of assets, net	$ 194	$ 1	$ 205	$ 3
Proceeds from Sale of Productive Assets			$ 345	$ 2
Martin County [Member]
Acquisitions and Divestitures [Line Items]
Gain (loss) on disposition of assets, net	194
Goodwill, Written off Related to Sale of Business Unit	2
Proceeds from Sale of Productive Assets	$ 266
Gas and Oil Area, Developed, Net | a	20,500		20,500
Production, Barrels of Oil Equivalents | Boe	1,500
Permian Basin [Member]
Acquisitions and Divestitures [Line Items]
Gain (loss) on disposition of assets, net			$ 10
Proceeds from Sale of Productive Assets			$ 77

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Plan Assets	$ 87	$ 83
Assets, Fair Value Disclosure	272	97
Liabilities, Fair Value Disclosure	4	84
Recurring Measurements, (Fair Value, Total)	268	13
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	87	83
Assets, Fair Value Disclosure	87	83
Liabilities, Fair Value Disclosure	0	0
Recurring Measurements, (Fair Value, Total)	87	83
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	185	14
Liabilities, Fair Value Disclosure	4	84
Recurring Measurements, (Fair Value, Total)	181	(70)
Fair Value, 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
Commodity Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	180	8
Derivative Liability, Fair Value, Net	3	84
Commodity Derivatives [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	0	0
Derivative Liability, Fair Value, Net	0	0
Commodity Derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	180	8
Derivative Liability, Fair Value, Net	3	84
Commodity Derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	0	0
Derivative Liability, Fair Value, Net	0	0
Diesel [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Net	1
Diesel [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Net	0
Diesel [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Net	1
Diesel [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Net	0
Interest Rate Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	5	6
Interest Rate Derivatives [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	0	0
Interest Rate Derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	5	6
Interest Rate Derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Net	$ 0	$ 0

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements (Nonrecurring Fair Value Measurements) (Details) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)$ / MMBTU$ / bbl	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)$ / MMBTU$ / bbl	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	$ 0		$ 0		$ (285,000)	$ (32,000)
Management oil price outlook | $ / bbl		53.65		49.77
Management gas price outlook | $ / MMBTU		3		3.24
Impairment of Long-Lived Assets Held-for-use				$ 32,000
Raton Field [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group		$ 186,000
Impairment of oil and gas properties		$ (285,000)
West Panhandle [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Asset Group				33,000
Impairment of oil and gas properties				$ (32,000)

Fair Value Measurements (Sche38

Fair Value Measurements (Schedule Of Carrying Values And Financial Instruments Not Carried At Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long-term debt	$ 449	$ 485
Long-term Debt, Excluding Current Maturities	2,281	2,728
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,726	1,906
Current portion of long-term debt	449	485
Long-term Debt, Excluding Current Maturities	2,281	2,728
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,723	1,901
Current portion of long-term debt	468	490
Long-term Debt, Excluding Current Maturities	$ 2,490	$ 2,956

Fair Value Measurements Fair 39

Fair Value Measurements Fair Value Measurements (Schedule of Cash and Cash Equivalents and Investments) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	$ 660	$ 1,118	$ 1,825	$ 1,391
Short-term Investments	1,539	1,441
Long-term Investments	187	420
Cash, Cash Equivalents, and Short-term Investments	2,386	2,979
Cash and Cash Equivalents [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	560	873
Short-term Investments	0	0
Long-term Investments	0	0
Cash, Cash Equivalents, and Short-term Investments	560	873
Commercial Paper [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	0	45
Short-term Investments	138	368
Long-term Investments	0	0
Cash, Cash Equivalents, and Short-term Investments	138	413
Corporate Bond Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	0	0
Short-term Investments	865	691
Long-term Investments	187	420
Cash, Cash Equivalents, and Short-term Investments	1,052	1,111
Bank Time Deposits [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	100	200
Short-term Investments	536	382
Long-term Investments	0	0
Cash, Cash Equivalents, and Short-term Investments	$ 636	$ 582

Derivative Financial Instrume40

Derivative Financial Instruments (Narrative) (Details) $ in Thousands	1 Months Ended
	Jul. 31, 2017USD ($)	Jun. 30, 2017USD ($)MMBTU / d$ / bblRate
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Fixed Interest Rate | Rate		1.81%
Notional amount of debt		$ 100,000
Diesel Swap Current Year [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		(1,000)
Derivative, Swap Type, Fixed Price | $ / bbl		63
Subsequent Event [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Proceeds from Termination of Diesel Derivatives	$ 321

Derivative Financial Instrume41

Derivative Financial Instruments (Schedule Of Oil Derivative Contracts Volume And Weighted Average Prices) (Details)	Jul. 31, 2017bbl / d$ / bbl	Jun. 30, 2017bbl / d$ / bbl
Oil contracts [Member] | Collar Contract For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		6,000
Oil contracts [Member] | Collar Contract For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		6,000
Oil contracts [Member] | Collar Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		0
Oil contracts [Member] | Collar Contracts With Short Puts For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		147,000
Oil contracts [Member] | Collar Contracts With Short Puts For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		155,000
Oil contracts [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		71,000
Oil contracts, price per bbl [Member] | Collar Contract For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price		70.40
Derivative, Average Floor Price		50
Oil contracts, price per bbl [Member] | Collar Contract For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price		70.40
Derivative, Average Floor Price		50
Oil contracts, price per bbl [Member] | Collar Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price		0
Derivative, Average Floor Price		0
Oil contracts, price per bbl [Member] | Collar Contracts With Short Puts For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price		62.03
Derivative, Average Floor Price		49.81
Derivative, Notional Amount, Price Per Unit		41.07
Oil contracts, price per bbl [Member] | Collar Contracts With Short Puts For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price		62.12
Derivative, Average Floor Price		49.82
Derivative, Notional Amount, Price Per Unit		41.02
Oil contracts, price per bbl [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price		60.38
Derivative, Average Floor Price		50.07
Derivative, Notional Amount, Price Per Unit		40
Subsequent Event [Member] | Oil contracts [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	26,000
Subsequent Event [Member] | Oil contracts, price per bbl [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	55.01
Derivative, Average Floor Price	45
Derivative, Notional Amount, Price Per Unit	35

Derivative Financial Instrume42

Derivative Financial Instruments Derivative Financial Instruments (Schedule of NGL Derivative Contracts Volume and Weighted Average Prices) (Details)	Jun. 30, 2017bbl / dMMBTU / d$ / MMBTU$ / bbl
NGL contract, in BBLS [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	2,500
NGL contract, MMBtu Equivalent [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,920
Butane [Member] | NGL contract, in BBLS [Member] | Collar Contracts With Short Puts For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	2,000
Butane [Member] | NGL contract, in BBLS [Member] | Collar Contracts With Short Puts For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	0
Butane [Member] | NGL contract, in BBLS [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	0
Butane [Member] | NGL contract, in BBLS [Member] | Collar Contracts With Short Puts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	0
Butane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts With Short Puts For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price	36.12
Derivative, Average Floor Price	29.25
Derivative, Notional Amount, Price Per Unit	23.40
Butane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts With Short Puts For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Derivative, Notional Amount, Price Per Unit	0
Butane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts With Short Puts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Derivative, Notional Amount, Price Per Unit	0
Butane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts With Short Puts for Year 3 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Derivative, Notional Amount, Price Per Unit	0
Ethane [Member] | NGL contract, in BBLS [Member] | Collar Contract For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Ethane [Member] | NGL contract, in BBLS [Member] | Collar Contract For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Ethane [Member] | NGL contract, in BBLS [Member] | Collar Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	0
Ethane [Member] | NGL contract, in BBLS [Member] | Collar Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	0
Ethane [Member] | NGL contracts, price per BBL [Member] | Collar Contract For Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price	11.83
Derivative, Average Floor Price	8.68
Ethane [Member] | NGL contracts, price per BBL [Member] | Collar Contract For Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Average Cap Price	11.83
Derivative, Average Floor Price	8.68
Ethane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Ethane [Member] | NGL contracts, price per BBL [Member] | Collar Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Average Cap Price	0
Derivative, Average Floor Price	0
Ethane [Member] | NGL contract, MMBtu Equivalent [Member] | Basis Swap Contracts for Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,920
Ethane [Member] | NGL contract, MMBtu Equivalent [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,920
Ethane [Member] | NGL contract, MMBtu Equivalent [Member] | Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,920
Ethane [Member] | NGL contract, MMBtu Equivalent [Member] | Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,920
Ethane [Member] | NGL contract, price per MMBtu Equivalent [Member] | Basis Swap Contracts for Third Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU	1.60
Ethane [Member] | NGL contract, price per MMBtu Equivalent [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU	1.60
Ethane [Member] | NGL contract, price per MMBtu Equivalent [Member] | Basis Swap Contracts for Year 2 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU	1.60
Ethane [Member] | NGL contract, price per MMBtu Equivalent [Member] | Basis Swap Contracts for Year 3 [Member]
Derivative [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU	1.60

Derivative Financial Instrume43

Derivative Financial Instruments Derivative Financial Instruments (Schedule of Gas Derivative Contracts Volume and Weighted Average Prices) (Details)	Jul. 31, 2017MMBTU / d$ / MMBTU	Jun. 30, 2017MMBTU / d$ / MMBTU
Collar Contracts With Short Puts For Third Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		290,000
Collar Contracts With Short Puts For Third Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Average Cap Price		3.57
Derivative, Average Floor Price		2.95
Derivative, Notional Amount, Price Per Unit		2.47
Collar Contracts With Short Puts For Fourth Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		300,000
Collar Contracts With Short Puts For Fourth Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Average Cap Price		3.60
Derivative, Average Floor Price		2.96
Derivative, Notional Amount, Price Per Unit		2.47
Collar Contracts With Short Puts for Year 2 [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		62,329
Collar Contracts With Short Puts for Year 2 [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Average Cap Price		3.56
Derivative, Average Floor Price		2.91
Derivative, Notional Amount, Price Per Unit		2.37
Mid-Continent [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		45,000
Mid-Continent [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		(0.32)
Mid-Continent [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		45,000
Mid-Continent [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		(0.32)
Mid-Continent [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		0
Mid-Continent [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		0
Permian Basin [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		0
Permian Basin [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		0
Permian Basin [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		26,522
Permian Basin [Member] | Basis Swap Contracts for Fourth Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		0.30
Permian Basin [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d		39,945
Permian Basin [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential		0.30
Permian Basin [Member] | Subsequent Event [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	6,739
Permian Basin [Member] | Subsequent Event [Member] | Basis Swap Contracts for Third Quarter of Year One [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential	0.26
Permian Basin [Member] | Subsequent Event [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, in MMBTU [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	11,726
Permian Basin [Member] | Subsequent Event [Member] | Basis Swap Contracts for Year 2 [Member] | Gas contracts, price per MMBTU [Member]
Derivative [Line Items]
Derivative, Swap Type, Price Differential	0.31

Derivative Financial Instrume44

Derivative Financial Instruments (Schedule Of Derivative Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Assets, Current	$ 156	$ 14
Derivative Assets, Noncurrent	29	0
Derivative Liabilities, Current	3	77
Derivative Liabilities, Noncurrent	1	7
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Net	185	14
Derivative Liability, Fair Value, Net	4	84
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Current [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross	153	33
Derivative Liability, Fair Value, Gross Liability	5	102
Derivative Assets Offset In Balance Sheet	(2)	(25)
Derivative Liabilities Offset In Balance Sheet	(2)	(25)
Derivative Assets, Current	151	8
Derivative Liabilities, Current	3	77
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Noncurrent [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross	30
Derivative Liability, Fair Value, Gross Liability	2	7
Derivative Assets Offset In Balance Sheet	(1)
Derivative Liabilities Offset In Balance Sheet	(1)	0
Derivative Assets, Noncurrent	29
Derivative Liabilities, Noncurrent	1	7
Not Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Derivatives - Current [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross	5	6
Derivative Assets Offset In Balance Sheet	0	0
Derivative Assets, Current	$ 5	$ 6

Derivative Financial Instrume45

Derivative Financial Instruments (Schedule Of Derivative Obligations Under Terminated Hedge Arrangements) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Derivative gains, net	$ 135	$ (229)	$ 286	$ (186)
Commodity Price Derivatives [Member] | Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains, net	136	(222)	287	(177)
Interest Rate Derivatives [Member] | Derivative Gains (Losses), Net [Member]
Derivative [Line Items]
Derivative gains, net	$ (1)	$ (7)	$ (1)	$ (9)

Exploratory Costs (Schedule Of

Exploratory Costs (Schedule Of Capitalized Exploratory Well And Project Activity) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Beginning capitalized exploratory costs	$ 432	$ 323
Additions to exploratory costs pending the determination of proved reserves	489	895
Reclassification due to determination of proved reserves	(477)	(765)
Exploratory well costs charged to exploration expense	(1)	(10)
Ending capitalized exploratory costs	$ 443	$ 443

Exploratory Costs Exploratory W

Exploratory Costs Exploratory Well Costs (Capitalized Exploratory Costs And the Number Of Projects For Which Exploratory Costs Have Been Capitalized) (Details) $ in Millions	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Line Items]
Capitalized Exploratory Well Costs that Have Been Capitalized for Period of One Year or Less	$ 420		$ 318
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	23		5
Capitalized Exploratory Well Costs	$ 443	$ 432	$ 323
Projects that have Exploratory Well Costs that have been Capitalized for Period Greater than One Year, Number of Projects	12		3

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2017	Jun. 30, 2017	Jun. 30, 2016
Debt Instrument [Line Items]
Maximum Borrowing Capacity		$ 1,500
Outstanding borrowing		0
Repayments of Long-term Debt		$ 485	$ 0
Six Point Six Five Percent Senior Notes Due Two Thousand Seventeen [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.65%
Repayments of Long-term Debt	$ 485
Six Point Eight Seven Five Percent Senior Notes Due Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.875%
Senior Notes		$ 450

Incentive Plans Incentive Plans

Incentive Plans Incentive Plans (Stock-based compensation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 27	$ 29	$ 57	$ 53
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	137		$ 137
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Restricted Stock Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	31		$ 31
Accounts Payable, Current	$ 10		$ 10		$ 22

Incentive Plans Incentive Pla50

Incentive Plans Incentive Plans (Share Based Incentive Award Activity) (Details) - shares	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Restricted Stock Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	945,958	1,077,227
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	320,103
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(437,845)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(13,527)
Restricted Stock Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	264,952	290,552
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	108,911
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(129,499)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(5,012)
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	237,600	178,556
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	59,044
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	159,378	159,378
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning asset retirement obligations	$ 297	$ 285	$ 297	$ 285
Asset Retirement Obligation, Liabilities Incurred	1	0	1	0
Changes in estimates	7	0	7	0
Disposition of wells	(7)	0	(7)	0
Liabilities settled	(9)	(9)	(14)	(13)
Accretion of discount from continuing operations	5	5	10	9
Ending asset retirement obligations	294	$ 281	294	$ 281
Asset retirement obligations, current portions	$ 46		$ 46		$ 39

Commitments And Contingencies C

Commitments And Contingencies Commitments and Contingencies (Details)	6 Months Ended
	Jun. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Pending Future Environmental Sanction Individual	$ 45,000
Pending Future Environmental Sanction Aggregate	100,000
Future Rent Expense	$ 33,000,000

Interest And Other Income (Comp

Interest And Other Income (Components Of Interest And Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest and Other Income [Abstract]
Interest income	$ 10	$ 5	$ 16	$ 9
Income Tax Credits and Adjustments	(5)	0	(8)	0
Deferred compensation plan income	1	0	3	2
Other income	0	1	3	2
Total interest and other income	$ 16	$ 6	$ 30	$ 13

Other Expense (Schedule Of Comp

Other Expense (Schedule Of Components Of Other Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Expense [Abstract]
Transportation commitment charges	$ 43	$ 25	$ 82	$ 50
Third-party vertical integration services	5	16	11	29
Above market and idle drilling and well services equipment charges	0	11	0	47
Other	11	15	26	28
Total other expense	59	67	119	154
GrossRevenuesIncludedInThirdPartyLossFromVerticalIntegrationServices	23	56	42	124
GrossExpensesIncludedInThirdPartyLossFromVerticalIntegrationServices	$ 28	$ 72	$ 53	$ 153

Income Taxes (Schedule Of Incom

Income Taxes (Schedule Of Income Tax (Provisions) Benefits Attributable To Income From Continuing Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Deferred income taxes	$ (121)	$ 143	$ (90)	$ 284
Income tax benefit (provision)	$ (121)	$ 143	$ (90)	$ 284
Effective Tax Rate	34.00%	35.00%	32.00%	35.00%
Statutory Tax Rate			35.00%
Effective Income Tax Rate Reconciliation, Deduction, Amount			$ 8
Unrecognized Tax Benefits	$ 119		$ 119		$ 112

Net Income Per Share (Reconcili

Net Income Per Share (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Operating Activities Segment [Line Items]
Income (loss) from continuing operations attributable to parent	$ 233	$ (268)	$ 191	$ (535)
Participating Securities, Distributed and Undistributed Earnings, Basic	(2)	0	(2)	0
Basic income (loss) from continuing operations attributable to common stockholders	231	(268)	189	(535)
Diluted income (loss) from continuing operations attributable to common stockholders	$ 231	$ (268)	$ 189	$ (538)

Net Income Per Share (Reconci57

Net Income Per Share (Reconciliation Of Basic To Diluted Weighted Average Common Shares Outstanding) (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted Average Number of Shares Outstanding Reconciliation [Line Items]
Basic weighted average shares outstanding	170	164	170	163
Diluted	170	164	170	163