Pioneer Natural Resources (PXD) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 05, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
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 Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		170,462,089

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 919	$ 896
Short-term investments	557	1,213
Accounts receivable:
Trade, net	876	644
Due from affiliates	0	1
Income taxes receivable	7	7
Inventories	269	212
Derivatives	1	11
Other	31	23
Total current assets	2,660	3,007
Oil and gas properties, using the successful efforts method of accounting:
Proved properties	20,173	20,404
Unproved properties	586	558
Accumulated depletion, depreciation and amortization	(7,828)	(9,196)
Total property, plant and equipment	12,931	11,766
Long-term investments	193	66
Goodwill	267	270
Other property and equipment, net	1,864	1,762
Other assets, net	109	132
Total Assets	18,024	17,003
Accounts payable:
Trade	1,447	1,174
Due to affiliates	108	108
Interest payable	25	59
Income taxes payable	2	0
Current portion of long-term debt	0	449
Derivatives	482	232
Other	161	106
Total current liabilities	2,225	2,128
Long-term debt	2,286	2,283
Derivatives	70	23
Deferred income taxes	1,064	899
Other liabilities	485	391
Equity:
Common stock, $.01 par value	2	2
Additional paid-in capital	9,041	8,974
Treasury stock at cost	(296)	(249)
Retained earnings	3,147	2,547
Total equity attributable to common stockholders	11,894	11,274
Noncontrolling interests in consolidated subsidiaries	0	5
Total equity	11,894	11,279
Commitments and contingencies
Total Liabilities and Equity	$ 18,024	$ 17,003

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	174,307,471	173,796,743
Treasury stock, shares	3,845,568	3,608,132

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues and other income:
Revenue	$ 2,458		$ 7,175
Interest and other	10	$ 17	40	$ 44
Derivative gains (losses), net	(135)	(133)	(701)	153
Gain on disposition of assets, net	143	0	226	205
Total revenues and other income	2,476	1,167	6,740	3,929
Costs and expenses:
Production and ad valorem taxes	83	53	229	152
Depletion, depreciation and amortization	394	355	1,130	1,033
Impairment of oil and gas properties	0	0	77	285
Exploration and abandonments	20	18	83	78
General and administrative	96	81	282	245
Accretion of discount on asset retirement obligations	3	5	11	14
Interest	30	37	97	118
Other	182	58	316	176
Costs and Expenses	1,947	1,201	5,900	3,682
Income (loss) before income taxes	529	(34)	840	247
Income tax benefit (provision)	(118)	11	(188)	(79)
Net income (loss)	411	(23)	652	168
Net loss attributable to noncontrolling interests	0	0	3	0
Net income (loss) attributable to common stockholders	$ 411	$ (23)	$ 655	$ 168
Net income (loss) per share attributable to common shareholders:
Basic (usd per share)	$ 2.40	$ (0.13)	$ 3.82	$ 0.98
Diluted (usd per share)	$ 2.39	$ (0.13)	$ 3.82	$ 0.98
Basic and diluted weighted average shares outstanding	171	170	171	170
Dividends declared per share (usd per share)	$ 0.16	$ 0.04	$ 0.32	$ 0.08
Oil and gas
Revenues and other income:
Revenue	$ 1,317	$ 855	$ 3,869	$ 2,433
Costs and expenses:
Costs and expenses	198	152	654	440
Sales of purchased oil and gas
Revenues and other income:
Revenue	1,141	428	3,306	1,094
Costs and expenses:
Costs and expenses	$ 941	$ 442	$ 3,021	$ 1,141

Consolidated Statement Of Equit

Consolidated Statement Of Equity - 9 months ended Sep. 30, 2018 - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Noncontrolling Interests
Beginning Balance, shares at Dec. 31, 2017		170,189
Beginning Balance at Dec. 31, 2017	$ 11,279	$ 2	$ 8,974	$ (249)	$ 2,547	$ 5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared ($0.32 per share)	(55)				(55)
Exercise of long-term incentive stock options and employee stock purchases, shares		58
Exercise of long-term incentive stock options and employee stock purchases	8		4	4
Purchases of treasury stock, shares		(296)
Purchases of treasury stock	(51)			(51)
Compensation costs:
Vested compensation awards, shares		511
Vested compensation awards	0	$ 0	0
Compensation costs included in net income	63		63			0
Sale of noncontrolling interest	(2)					(2)
Net income	652				655	(3)
Ending Balance, shares at Sep. 30, 2018		170,462
Ending Balance at Sep. 30, 2018	$ 11,894	$ 2	$ 9,041	$ (296)	$ 3,147	$ 0

Consolidated Statement Of Equ_2

Consolidated Statement Of Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (usd per share)	$ 0.16	$ 0.04	$ 0.32	$ 0.08

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 652	$ 168
Adjustments to reconcile net income to net cash provided by operating activities:
Depletion, depreciation and amortization	1,130	1,033
Impairment of oil and gas properties	77	285
Impairment of inventory and other property and equipment	9	1
Exploration expenses, including dry holes	12	19
Deferred income taxes	186	79
Gain on disposition of assets, net	(226)	(205)
Accretion of discount on asset retirement obligations	11	14
Interest expense	4	4
Derivative related activity	307	(91)
Amortization of stock-based compensation	63	61
Other	176	58
Change in operating assets and liabilities:
Accounts receivable	(233)	(131)
Income taxes receivable	0	(2)
Inventories	(70)	(9)
Investments	4	(2)
Other current assets	(1)	(4)
Accounts payable	305	82
Interest payable	(34)	(30)
Income taxes payable	2	0
Other current liabilities	(46)	(33)
Net cash provided by operating activities	2,328	1,301
Cash flows from investing activities:
Proceeds from disposition of assets	383	347
Proceeds from investments	1,140	1,196
Purchase of investments	(618)	(850)
Additions to oil and gas properties	(2,495)	(1,703)
Additions to other assets and other property and equipment, net	(187)	(252)
Net cash used in investing activities	(1,777)	(1,262)
Cash flows from financing activities:
Principal payments on long-term debt	(450)	(485)
Exercise of long-term incentive plan stock options and employee stock purchases	8	7
Purchases of treasury stock	(51)	(36)
Payments of other liabilities	(8)	0
Dividends paid	27	7
Net cash used in financing activities	(528)	(521)
Net increase (decrease) in cash and cash equivalents	23	(482)
Cash and cash equivalents, beginning of period	896	1,118
Cash and cash equivalents, end of period	$ 919	$ 636

Organization and Nature of Oper

Organization and Nature of Operations	9 Months Ended
	Sep. 30, 2018
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. In February 2018, the Company announced its intention to divest its properties in the South Texas, Raton and West Panhandle fields and focus its efforts and capital resources on its Permian Basin assets. Thus far into 2018, the Company has accomplished the following: • In April 2018, the Company completed the sale of approximately 10,200 net acres in the western portion of the Eagle Ford Shale ("West Eagle Ford Shale") to an unaffiliated third party for cash proceeds of $103 million , before normal closing adjustments. • In July 2018, the Company completed the sale of its assets in the Raton Basin to an unaffiliated third party for cash proceeds of $79 million , before normal closing adjustments. • In August 2018, the Company completed the sale of its assets in the West Panhandle field to an unaffiliated third party for cash proceeds of $201 million , before normal closing adjustments. • In October 2018, the Company entered into a purchase and sale agreement to sell approximately 2,900 net acres in the Sinor Nest (Lower Wilcox) field in South Texas to an unaffiliated third party for cash proceeds of $132 million , before normal closing adjustments . See Note 3 for further information regarding the sale of the Company's West Eagle Ford Shale, Raton Basin and West Panhandle field assets and Note 16 for further information regarding the Company's sale of its Sinor Nest assets in South Texas. No assurance can be given that the remaining planned divestiture of the Company's South Texas assets will be completed in accordance with the Company's plan or on terms and at prices acceptable to the Company.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 and for the three and nine months ended September 30, 2018 and 2017 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, 2017 . Certain reclassifications have been made to the 2017 financial statement and footnote amounts in order to conform to the 2018 presentation. Accounting policy changes. During the second quarter of 2018, the Company made a voluntary change in accounting policy to account for its materials and supplies inventory on a weighted average cost basis, versus using the previous accounting policy of the first-in-first-out (“FIFO”) basis. The Company made this voluntary change in accounting policy because it believes this method is preferable, as the weighted average cost basis more closely aligns with the physical flow of material and supplies inventory and is more widely utilized in the oil and gas industry. This voluntary change in accounting policy did not have a material effect on the Company’s consolidated financial statements for prior periods. As such, prior periods have not been restated. Adoption of new accounting standards. In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-04, "Simplifying the Test of Goodwill Impairment." ASU 2017-04 simplifies the quantitative goodwill impairment test by eliminating the requirement to calculate the implied fair value of goodwill (step 2 of the current goodwill impairment test). Instead, a company would record an impairment charge based on the excess of a reporting unit's carrying value over its fair value (as measured in step 1 of the current goodwill impairment test). ASU 2017-04 is effective for fiscal years beginning after December 15, 2019, with early adoption permitted. In July 2018, the Company elected to early adopt this update. The adoption of ASU 2017-04 had no impact on the Company's consolidated financial statements. The Company will perform future goodwill impairment tests in accordance with ASU 2017-04. In May 2014, the FASB issued ASU No. 2014-09 ("ASC 606"), "Revenue from Contracts with Customers," which supersedes the revenue recognition requirements in ASC 605, "Revenue Recognition" ("ASC 605"), and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company adopted ASC 606 as of January 1, 2018 using the modified retrospective transition method. See Note 11 for a discussion of the impact to the Company's recognition of revenue associated with the adoption of ASC 606. In March 2016, the FASB issued 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 14 for a discussion of the impact to the Company's income tax provision associated with the adoption of ASU 2016-09. New accounting pronouncements. 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 accounting for lease expenses. This standard is effective for fiscal years beginning after December 15, 2018 and for interim periods beginning the following year. This ASU should be applied using a modified retrospective approach, and early adoption is permitted. This standard does not apply to leases to explore for or use minerals, oil or gas resources, including the right to explore for those natural resources and rights to use the land in which those natural resources are contained. Based on its current commitments, the Company anticipates it will be required to recognize lease assets and liabilities related to drilling rig commitments, certain equipment rentals and leases, certain surface use agreements and potentially other arrangements. The Company is evaluating the impact of the adoption of ASU 2016-02 on its consolidated results of operations, financial position and financial disclosures and developing any necessary control changes. The Company plans to apply certain practical expedients provided in ASU 2016-02 that, among other things, allow entities to not reassess contracts that commenced prior to adoption and to not recognize right of use assets and lease liabilities related to short-term leases.

Divestitures

Divestitures	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Divestitures	Divestitures Acquisitions In September 2018, the Company (i) purchased from an unaffiliated third party an interest in sand reserves in West Texas for $17 million and (ii) entered into a long-term sand processing and supply agreement with the operator of the sand mine. This agreement secures a long-term supply of sand beginning in the first quarter of 2019. The sand mine operator will process and supply 30 million tons of processed sand to Pioneer over 15 years . The Company recorded its investment in these sand reserves to other property and equipment in the accompanying consolidated balance sheet during the third quarter of 2018. Divestitures In February 2018, the Company announced its intention to divest its properties in the South Texas, Raton and West Panhandle fields and focus its efforts and capital resources on its Permian Basin assets. In April 2018, the Company completed the sale of approximately 10,200 net acres in the West Eagle Ford Shale to an unaffiliated third party for cash proceeds of $103 million , before normal closing adjustments . During the nine months ended September 30, 2018 , the Company recognized a gain of $75 million associated with this divestiture. In conjunction with this divestiture, the Company reduced the carrying value of goodwill by $1 million , reflecting the portion of the Company's goodwill related to the assets sold. In July 2018, the Company completed the sale of its Raton Basin assets to an unaffiliated third party for cash proceeds of $79 million , before normal closing adjustments . The Company recorded a noncash impairment charge of $77 million in June 2018 to reduce the carrying value of its Raton Basin assets to their estimated fair value less costs to sell as the assets were considered held for sale. See Note 4 for additional information about the Raton Basin impairment charge. During the three and nine months ended September 30, 2018 , the Company recognized a gain of $2 million associated with this divestiture. The Company recognized divestiture charges related to the Raton Basin sale of $117 million and $123 million in other expense during the three and nine months ended September 30, 2018 , respectively, primarily attributable to employee severance costs and deficiency charges related to certain firm transportation contracts retained by the Company. Additionally, the Company reduced the carrying value of goodwill by $1 million , reflecting the portion of the Company's goodwill related to assets sold. In August 2018, the Company completed the sale of its assets in the West Panhandle field to an unaffiliated third party for cash proceeds of $201 million , before normal closing adjustments . The assets sold represent all of the Company's interests in the field, including all of its producing wells and the associated infrastructure. Associated with this sale, the Company recognized a gain of $146 million and divestiture related charges of $6 million associated with employee severance costs during the three and nine months ended September 30, 2018 . Additionally, the Company reduced the carrying value of goodwill by $1 million , reflecting the portion of the Company's goodwill related to the assets sold. In its accompanying consolidated balance sheets as of September 30, 2018 , the Company had divestiture related liabilities of $42 million and $68 million recorded in other current and noncurrent liabilities, respectively, associated with expected deficiency charges on firm transportation contracts retained by the Company and $10 million recorded in accounts payable - due to affiliates associated with employee severance payments. The Company had no divestiture related liabilities as of December 31, 2017 . No assurance can be given that the remaining planned divestiture of the Company's South Texas assets will be completed in accordance with the Company's plan or on terms and at prices acceptable to the Company. 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 $264 million . The sale resulted in a gain of $194 million . In conjunction with this divestiture, 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 nine months ended September 30, 2017 , the Company also completed the sales of other nonstrategic proved and unproved properties in the Permian Basin for cash proceeds of $75 million , which resulted in a gain of $12 million .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 and December 31, 2017 for each of the fair value hierarchy levels: Fair Value Measurement as of September 30, 2018 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 September 30, 2018 (in millions) Assets: Commodity derivatives $ — $ 1 $ — $ 1 Deferred compensation plan assets 90 — — 90 Total assets 90 1 — 91 Liabilities: Commodity derivatives — 552 — 552 Total liabilities — 552 — 552 Total recurring fair value measurements $ 90 $ (551 ) $ — $ (461 ) Fair Value Measurement as of December 31, 2017 Using Quoted Prices Significant Significant Fair value as of December 31, 2017 (in millions) Assets: Commodity derivatives $ — $ 11 $ — $ 11 Deferred compensation plan assets 95 — — 95 Total assets 95 11 — 106 Liabilities: Commodity derivatives — 255 — 255 Total liabilities — 255 — 255 Total recurring fair value measurements $ 95 $ (244 ) $ — $ (149 ) Commodity derivatives. The Company's commodity derivatives represent oil, NGL and gas swap contracts, collar contracts, collar contracts with short puts and basis swap contracts. The asset and liability measurements for the Company's commodity derivative contracts represent Level 2 inputs in the hierarchy. The Company utilizes discounted cash flow and option-pricing models for valuing its commodity derivatives. The asset and liability values attributable to the Company's commodity derivatives were determined based on inputs that include (i) the contracted notional volumes, (ii) independent active market price quotes, (iii) the applicable estimated credit-adjusted risk-free rate yield curve and (iv) the implied rate of volatility inherent in the collar 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 September 30, 2018 and December 31, 2017 , the significant inputs to these asset exchange values represented Level 1 independent active exchange market price inputs. Assets and liabilities measured at fair value on a nonrecurring basis. Certain assets and liabilities are measured at fair value on a nonrecurring basis. These assets and liabilities are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances. These assets and liabilities can include inventory, proved and unproved oil and gas properties and other long-lived assets that are written down to fair value when they are impaired or held for sale. Proved oil and gas properties . As a result of the Company's proved property impairment assessments, the Company recognized a noncash impairment charge of $285 million to reduce the carrying value of the Raton Basin field during the three months ended March 31, 2017 to its estimated fair value of $186 million . The Company calculated the fair value of the Raton Basin field as of March 31, 2017 using a discounted future cash flow model. Significant Level 3 assumptions associated with the calculation of the Raton Basin field's discounted future cash flows as of March 31, 2017 included management's longer-term commodity price outlook ("Management's Price Outlook") for oil of $53.65 per barrel ("Bbl") and gas of $3.00 per million British Thermal units ("MMBtu") and management's outlook for (i) production, (ii) capital expenditures, (iii) production costs 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. It is reasonably possible that the Company's estimate of undiscounted future net cash flows attributable to 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. Sale of Raton Basin assets. In June 2018, the Company recognized an impairment charge of $77 million to reduce the carrying value of its Raton Basin field assets to the agreed upon sales price for these assets, as the assets were considered held for sale as of June 30, 2018. See Note 3 for additional information about the Company's sale of its Raton Basin field assets. 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 September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value (in millions) Commercial paper, corporate bonds and time deposits $ 750 $ 749 $ 1,279 $ 1,277 Current portion of long-term debt $ — $ — $ 449 $ 457 Long-term debt $ 2,286 $ 2,386 $ 2,283 $ 2,479 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, such investments are reflected in short-term investments or long-term investments in the accompanying consolidated balance sheets based on their maturity dates. The following tables provide the components of the Company's cash and cash equivalents and investments as of September 30, 2018 and December 31, 2017 : September 30, 2018 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Deposits Total (in millions) Cash and cash equivalents $ 869 $ — $ — $ 50 $ 919 Short-term investments — 131 275 151 557 Long-term investments — — 193 — 193 $ 869 $ 131 $ 468 $ 201 $ 1,669 December 31, 2017 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Total (in millions) Cash and cash equivalents $ 846 $ — $ — $ 50 $ 896 Short-term investments — 124 642 447 1,213 Long-term investments — — 66 — 66 $ 846 $ 124 $ 708 $ 497 $ 2,175 Debt obligations. The Company's debt obligations are composed of its senior notes whose fair value is determined utilizing inputs that are Level 2 measurements in the fair value hierarchy. The Company's senior notes represent debt securities that are quoted but not actively traded on major exchanges; therefore, 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	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company utilizes commodity swap contracts, collar contracts, collar contracts with short puts and basis swap contracts to (i) reduce the effect of price volatility on the commodities the Company produces and sells or consumes, (ii) support the Company's annual capital budgeting and expenditure plans and (iii) reduce commodity price risk associated with certain capital projects. The Company also, from time to time, utilizes interest rate contracts to reduce the effect of interest rate volatility on the Company's indebtedness. Oil production derivative activities. The Company sells its oil production at the lease and the sales contracts governing such oil production are tied directly to, or are highly correlated with, New York Mercantile Exchange ("NYMEX") West Texas Intermediate ("WTI") oil prices. The Company also periodically enters into pipeline capacity commitments in order to secure available oil transportation capacity to the Gulf Coast. In order to diversify the oil price it receives, the Company (i) enters into oil purchase transactions with third parties in its areas of production that are tied to NYMEX WTI oil prices, (ii) transports the purchased oil using its pipeline capacity to the Gulf Coast, and (iii) enters into third party sale transactions to sell the oil into the Gulf Coast refinery or international export markets at prices that are highly correlated with Brent oil prices. As a result, the Company uses NYMEX WTI and Brent derivative contracts to manage oil price volatility and basis swap contracts to reduce basis risk between NYMEX and Brent 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 September 30, 2018 and the weighted average oil prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Brent swap contracts (a): Volume (Bbl) — 10,000 Price per Bbl — $ 70.00 Brent collar contracts with short puts (b): Volume (Bbl) — 5,000 Price per Bbl: Ceiling $ — $ 87.00 Floor $ — $ 75.00 Short put $ — $ 65.00 NYMEX collar contracts: Volume (Bbl) 3,000 — Price per Bbl: Ceiling $ 58.05 $ — Floor $ 45.00 $ — NYMEX collar contracts with short puts: Volume (Bbl) 159,000 55,000 Price per Bbl: Ceiling $ 57.62 $ 60.13 Floor $ 47.26 $ 52.27 Short put $ 37.23 $ 42.27 ____________________ (a) Subsequent to September 30, 2018 , the Company liquidated its Brent swap contracts for cash payments of $5 million . (b) Subsequent to September 30, 2018 , the Company entered into additional Brent collar contracts with short puts for 10,000 Bbls per day of 2019 production with a ceiling price of $91.36 per Bbl, a floor price of $75.00 per Bbl and a short put price of $65.00 per Bbl. NGL production derivative activities. All material physical sales contracts governing the Company's NGL production are tied directly or indirectly to either Mont Belvieu, Texas or Conway, Kansas NGL component product prices. The Company uses derivative contracts to manage NGL component price volatility. The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of September 30, 2018 and the weighted average NGL prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Ethane basis swap contracts (a): Volume (MMBtu) 6,920 6,920 Price differential ($/MMBtu) $ 1.60 $ 1.60 ____________________ (a) The ethane basis swap contracts reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. The ethane 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. Subsequent to September 30, 2018 , the Company liquidated its ethane basis swap contracts for cash payments of $4 million . 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 September 30, 2018 and the weighted average gas prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Swap contracts (a): Volume (MMBtu) 101,348 647 Price per MMBtu $ 3.00 $ 3.11 Collar contracts with short puts: Volume (MMBtu) 50,000 — Price per MMBtu: Ceiling $ 3.40 $ — Floor $ 2.75 $ — Short put $ 2.25 $ — Basis swap contracts: Permian Basin index swap volume (MMBtu) (b) 58,652 44,230 Price differential ($/MMBtu) $ (1.46 ) $ (1.46 ) Southern California index swap volume (MMBtu) (c) 66,522 84,932 Price differential ($/MMBtu) $ 0.50 $ 0.33 ____________________ (a) Subsequent to September 30, 2018 , the Company entered into additional swap contracts for 50,000 MMBtu per day of January through March 2019 production with an average fixed price of $3.24 per MMBtu. (b) The referenced basis swap contracts fix the basis differentials between the index price at which the Company sells its Permian Basin gas and the HH price used in swap contracts and collar contracts with short puts. (c) The referenced basis swap contracts fix the basis differentials between Permian Basin index prices and southern California index prices for Permian Basin gas forecasted for sale in Arizona and southern California. Other derivatives. Periodically, the Company enters into gas swap contracts to mitigate gas price risk. As of September 30, 2018 , the Company was party to November 2018 through March 2019 gas swap contracts for 4,500 MMBtu per day at an average fixed price of $1.58 per MMBtu. The Company will receive Permian Basin index prices in exchange for paying the fixed price. Tabular disclosure of derivative financial instruments . All of the Company's derivatives are accounted for as non-hedge derivatives as of September 30, 2018 and December 31, 2017 , 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 September 30, 2018 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 $ 7 $ (6 ) $ 1 Commodity price derivatives Derivatives - noncurrent $ 1 $ (1 ) — $ 1 Liability Derivatives: Commodity price derivatives Derivatives - current $ 488 $ (6 ) $ 482 Commodity price derivatives Derivatives - noncurrent $ 71 $ (1 ) 70 $ 552 Fair Value of Derivative Instruments as of December 31, 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 $ 13 $ (2 ) $ 11 Commodity price derivatives Derivatives - noncurrent $ 3 $ (3 ) — $ 11 Liability Derivatives: Commodity price derivatives Derivatives - current $ 234 $ (2 ) $ 232 Commodity price derivatives Derivatives - noncurrent $ 26 $ (3 ) 23 $ 255 The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations: Derivatives Not Designated as Hedging Instruments Location of Gain/(Loss) Recognized in Earnings on Derivatives Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Commodity price derivatives Derivative gains (losses), net $ (135 ) $ (133 ) $ (701 ) $ 154 Interest rate derivatives Derivative gains (losses), net — — — (1 ) Total $ (135 ) $ (133 ) $ (701 ) $ 153 Derivative Counterparties . The Company uses credit and other financial criteria to evaluate the credit standing of, and to select, counterparties to its derivative instruments. Although the Company does not obtain collateral or otherwise secure the fair value of its derivative instruments, associated credit risk is mitigated by the Company's credit risk policies and procedures.

Exploratory Costs

Exploratory Costs	9 Months Ended
	Sep. 30, 2018
Extractive Industries [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 nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in millions) Beginning capitalized exploratory well costs $ 575 $ 505 Additions to exploratory well costs pending the determination of proved reserves 607 1,820 Reclassification due to determination of proved reserves (554 ) (1,689 ) Disposition of assets (1 ) (1 ) Exploratory well costs charged to exploration and abandonment expense (1 ) (9 ) Ending capitalized exploratory well costs $ 626 $ 626 The following table provides an aging as of September 30, 2018 and December 31, 2017 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: September 30, 2018 December 31, 2017 (in millions, except well counts) Capitalized exploratory well costs that have been suspended: One year or less $ 614 $ 493 More than one year 12 12 $ 626 $ 505 Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year 7 7 All projects with exploratory well costs that have been suspended for a period greater than one year as of September 30, 2018 are in the Eagle Ford Shale area. The Company is evaluating both the well performance of similar wells completed in 2017 and whether to drill additional wells near these wells in order for all of the wells in the area to be fracture stimulated as a package, thereby improving the resource recovery for the area. The Company expects to complete its evaluation of these wells during 2018.

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2018
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 . The Credit Facility had an original maturity date of August 2020, but in October 2018, the maturity date was extended to October 2023 (see Note 16 for additional information regarding the Credit Facility extension). As of September 30, 2018 , the Company had no outstanding borrowings under the Credit Facility and was in compliance with its debt covenants. Senior notes. The Company's 6.875% senior notes (the " 6.875% Senior Notes") and 6.65% senior notes (the " 6.65% Senior Notes"), with debt principal balances of $450 million and $485 million , respectively, matured and were repaid in May 2018 and March 2017, respectively. The Company funded the repayments with cash on hand. The 6.875% Senior Notes were classified as current in the accompanying consolidated balance sheet at December 31, 2017 .

Incentive Plans

Incentive Plans	9 Months Ended
	Sep. 30, 2018
Compensation Related Costs [Abstract]
Incentive Plans	Incentive Plans Stock-based compensation. For the three and nine months ended September 30, 2018 , the Company recorded $27 million and $79 million , respectively, of stock-based compensation expense for all plans, as compared to $21 million and $78 million for the same respective periods in 2017 . As of September 30, 2018 , there was $111 million of unrecognized stock-based compensation expense related to unvested share-based compensation plans, including $24 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 September 30, 2018 and December 31, 2017 , accounts payable – due to affiliates included $13 million and $20 million , respectively, of liabilities attributable to Liability Awards. The following table summarizes the activity that occurred during the nine months ended September 30, 2018 for restricted stock awards and performance units issued by the Company: Restricted Stock Equity Awards Restricted Stock Liability Awards Performance Units Outstanding as of December 31, 2017 916,223 252,735 163,158 Awards granted 390,618 113,231 62,541 Awards forfeited (45,877 ) (19,164 ) (1,285 ) Awards vested (426,541 ) (131,496 ) (34,778 ) Outstanding as of September 30, 2018 834,423 215,306 189,636 As of September 30, 2018 and December 31, 2017 , the Company also had 131,630 and 138,493 , respectively, of stock options outstanding and exercisable. There were 6,863 stock options exercised during the nine months ended September 30, 2018 .

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2018
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 nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Beginning asset retirement obligations $ 185 $ 294 $ 271 $ 297 New wells placed on production 1 — 2 2 Changes in estimates — — 2 7 Dispositions (10 ) — (89 ) (7 ) Liabilities settled (5 ) (7 ) (23 ) (21 ) Accretion of discount 3 5 11 14 Ending asset retirement obligations $ 174 $ 292 $ 174 $ 292 The Company records the current and noncurrent portions of asset retirement obligations in other current liabilities and other liabilities, respectively, in the accompanying consolidated balance sheets. As of September 30, 2018 and December 31, 2017 , the current portion of the Company's asset retirement obligations was $28 million and $41 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal actions. The Company is a party to various proceedings and claims incidental to its business. While many of these matters involve inherent uncertainty, the Company believes that the amount of the liability, if any, ultimately incurred with respect to 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. Obligations following divestitures. In connection with its divestiture transactions, the Company may retain certain liabilities, provide the purchaser certain indemnifications and provide credit support or guarantees for obligations that are transferred, subject to defined limitations, which may apply to identified pre-closing matters, including matters of litigation, environmental contingencies, royalty and transportation 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. Texas Commission on Environmental Quality ("TCEQ") enforcement action. The Company has been advised by the TCEQ that the agency is pursuing an enforcement action against the Company and may seek monetary sanctions due to various emissions occurring during the Company's ownership of the recently sold Fain gas plant in the West Panhandle region of Texas. The Company has engaged in discussions with the TCEQ 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 $525,000 in the aggregate. Lease agreements. In June 2017, the Company entered into a 20 -year operating lease for the Company's new corporate headquarters that is currently being constructed in Irving, Texas. Annual base rent is expected to be $33 million and lease payments are expected to commence once the building is complete, which is anticipated to occur during the second half of 2019. The Company has a variable equity interest in the entity that is constructing the building. The Company is not the primary beneficiary of the variable interest entity and only has a profit sharing interest after certain economic returns are achieved. The Company has no exposure to the variable interest entity's losses or future liabilities, if any. The Company is the deemed owner of the building (for accounting purposes) during the construction period and is following the build-to-suit accounting guidance. Accordingly, as of September 30, 2018 , the Company has capitalized $170 million of construction costs, including capitalized interest, within other property and equipment and has recognized a corresponding build-to-suit lease liability. The recording of these assets and liabilities are considered noncash investing and financing items, respectively, for purposes of the consolidated statements of cash flows. Firm purchase, gathering, processing, transportation, and fractionation commitments. The Company from time to time enters into, and as of September 30, 2018 was a party to, take-or-pay agreements, which include contractual commitments to purchase and process sand and purchase water for use in the Company's drilling operations and contractual commitments with midstream service companies and pipeline carriers for future gathering, processing, transportation, storage and fractionation. These commitments are normal and customary for the Company's business activities.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Impact of ASC 606 adoption. On January 1, 2018, the Company adopted ASC 606 by applying the modified retrospective method to all revenue contracts as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with historic accounting under ASC 605. The Company completed a detailed review of its revenue contracts, which represent all of the Company's revenue streams including oil, NGL and gas sales and sales of purchased oil and gas, to determine the effect of the new standard for the three and nine months ended September 30, 2018 . The Company did not record a change to its opening retained earnings as of January 1, 2018 as there was no material change to the timing or pattern of revenue recognition due to the adoption of ASC 606. The adoption of ASC 606 as of January 1, 2018 had the following impact on the Company's results of operations for the three and nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 As Reported ASC 605 (Without Adoption of ASC 606) Effect of Change Higher (Lower) As Reported ASC 605 Effect of Change (in millions) (in millions) Revenues and other income: Oil and gas $ 1,317 $ 1,258 $ 59 $ 3,869 $ 3,713 $ 156 Costs and expenses: Oil and gas production $ 198 $ 139 $ 59 $ 654 $ 498 $ 156 Changes in oil and gas revenues and oil and gas production costs (specifically gathering, processing and transportation costs) are due to the conclusion under the control model in ASC 606 that the third-party processor or transporter is only providing gas processing or transportation services and that the Company remains the principal owner of the commodity until sold to the ultimate purchaser. This is a change from ASC 605 where the Company historically recorded gas processing fees as a reduction of revenue recognized by the Company, as these fees were considered necessary to separate the wet gas stream into its sellable components (i.e., dry gas and individual NGL components). Under ASC 605, third-party processing and transportation companies were determined to have control of the commodities being processed and transported. As a result of adopting ASC 606, the Company has modified its presentation of revenues and expenses for these arrangements. Revenues related to these agreements are now presented on a gross basis for amounts expected to be received from third-party purchasers through the marketing process. Gathering, processing and transportation expenses related to these agreements, incurred prior to the transfer of control to the purchaser, are now presented as oil and gas production costs. Disaggregated revenue from contracts with purchasers. Revenues on sales of oil, NGLs, gas and purchased oil and gas are recognized when control of the product is transferred to the purchaser and payment can be reasonably assured. Sales prices for oil, NGL and gas production are negotiated based on factors normally considered in the industry, such as an index or spot price, distance from the well to the pipeline or market, commodity quality and prevailing supply and demand conditions. As such, the prices of oil, NGLs and gas generally fluctuate based on the relevant market index rates. The following table provides information about disaggregated revenue from contracts with purchasers by product type: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in millions) Oil sales $ 1,033 $ 3,079 NGL sales 207 542 Gas sales 77 248 Total oil and gas sales 1,317 3,869 Sales of purchased oil 1,127 3,261 Sales of purchased gas 14 45 Total sales of purchased oil and gas 1,141 3,306 Total revenue derived from contracts with purchasers $ 2,458 $ 7,175 Oil sales . Sales under the Company's oil contracts are generally considered performed when the Company sells oil production at the wellhead and receives an agreed-upon index price, net of any price differentials. The Company recognizes revenue when control transfers to the purchaser at the wellhead based on the net price received. NGL and gas sales . The Company evaluated whether it was the principal or the agent in natural gas processing transactions and concluded that it is the principal when it has the ability to take-in-kind, which is the case in the majority of the Company's gas processing and transportation contracts. Therefore, beginning January 1, 2018, the Company began recognizing revenue on a gross basis, with the gathering, processing and transportation costs associated with its take-in-kind arrangements being recognized as oil and gas production costs in the Company's accompanying consolidated statement of operations. Gas and NGL processing fees previously reflected as a reduction in the Company's reported gas and NGL revenue are now recognized as an expense in the Company's production costs. Sales of purchased oil and gas . The Company periodically enters into pipeline capacity commitments in order to secure available oil, NGL and gas transportation capacity from the Company's areas of production. The Company enters into purchase transactions with third parties and separate sale transactions with third parties to diversify a portion of the Company's WTI oil sales to the Gulf Coast refinery or international export markets and to satisfy unused pipeline capacity commitments. Revenues and expenses from these transactions are presented on a gross basis as the Company acts as a principal in the transaction by assuming control of the commodities purchased and the responsibility to deliver the commodities sold. Revenue is recognized when control transfers to the purchaser at the delivery point based on the price received from the purchaser. The transportation costs associated with these transactions are presented as a component of purchased oil and gas expense. Firm transportation payments on excess pipeline capacity are included in other expense in the accompanying consolidated statements of operations. Performance obligations and contract balances. The majority of the Company's product sale commitments are short-term in nature with a contract term of one year or less. The Company typically satisfies its performance obligations upon transfer of control as described above in Disaggregated revenue from contracts with purchasers and records the related revenue in the month production is delivered to the purchaser. Settlement statements for sales of oil, NGLs and gas and sales of purchased oil and gas may not be received for 30 to 60 days after the date the volumes are delivered, and as a result, the Company is required to estimate the amount of volumes delivered to the purchaser and the price that will be received for the sale of the product. The Company records the differences between estimates and the actual amounts received for product sales in the month that payment is received from the purchaser. The implementation of ASC 606 has not changed existing controls around revenue estimates and the accrual process. Historically, differences between the Company's revenue estimates and actual revenue received have not been significant. As of September 30, 2018 and December 31, 2017 , the accounts receivable balance representing amounts due or billable under the terms of contracts with purchasers was $806 million and $594 million , respectively.

Interest and Other Income

Interest and Other Income	9 Months Ended
	Sep. 30, 2018
Interest and Other Income [Abstract]
Interest and Other Income	Interest and Other Income The following table provides the components of the Company's interest and other income for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Interest income $ 7 $ 9 $ 21 $ 25 Deferred compensation plan income 3 1 6 3 Other income — 2 7 3 Seismic data sales — — 5 — Production and sales tax refunds — 5 1 13 Total interest and other income $ 10 $ 17 $ 40 $ 44

Other Expense

Other Expense	9 Months Ended
	Sep. 30, 2018
Other Income and Expenses [Abstract]
Other Expense	Other Expense The following table provides the components of the Company's other expense for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Transportation commitment charges (a) $ 43 $ 45 $ 121 $ 127 Legal and environmental charges 6 2 18 9 Loss (income) from vertical integration services (b) (5 ) — 5 11 Asset divestiture related charges (c) 123 — 132 — Other 15 11 40 29 Total other expense $ 182 $ 58 $ 316 $ 176 ____________________ (a) Primarily represents firm transportation payments on excess pipeline capacity commitments. (b) Loss (income) 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 nine months ended September 30, 2018 , these vertical integration net margins included $49 million and $113 million , respectively, of revenues and $44 million and $118 million , respectively, of costs and expenses. For the same respective periods in 2017, these vertical integration net margins included $42 million and $84 million of revenues and $42 million and $95 million of costs and expenses. (c) Primarily represents severance and firm transportation commitments associated with the Company's divestiture of its properties in the Raton and West Panhandle fields. See Note 3 for additional information on these charges.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's income tax benefit (provision) consisted of the following for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Current tax provision $ (2 ) $ — $ (2 ) $ — Deferred tax benefit (provision) (116 ) 11 (186 ) (79 ) Income tax benefit (provision) $ (118 ) $ 11 $ (188 ) $ (79 ) For both the three and nine months ended September 30, 2018 , the Company's effective tax rate, excluding net loss attributable to noncontrolling interests, was 22 percent , as compared to an effective rate of 34 percent and 32 percent for the same respective periods in 2017 . The U.S. statutory rate for the three and nine months ended September 30, 2018 was 21 percent , reflecting the reduction in the federal corporate income tax rate from 35 percent to 21 percent beginning in 2018 as a result of the Tax Cuts and Jobs Act that was enacted in December 2017. The Company's effective tax rate for the nine months ended September 30, 2017 differs from the U.S. statutory rate in effect during 2017 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 September 30, 2018 and December 31, 2017 , the Company had cumulative unrecognized tax benefits of $135 million and $124 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 effective tax rate in the period it is recognized. The timing as to when the Company will substantially resolve the uncertainties associated with the unrecognized tax benefit is uncertain. 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 2012. As of September 30, 2018 , no adjustments had been proposed in any jurisdiction that would have a significant effect on the Company's liquidity, future results of operations or financial position.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income (Loss) 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 nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Net income (loss) attributable to common stockholders $ 411 $ (23 ) $ 655 $ 168 Participating share-based earnings (2 ) — (3 ) (1 ) Basic and diluted net income (loss) attributable to common stockholders $ 409 $ (23 ) $ 652 $ 167 Basic and diluted weighted average common shares outstanding were 171 million for both the three and nine months ended September 30, 2018 and 170 million for both the three and nine months ended September 30, 2017 . Stock repurchase program . In February 2018, the Company's board of directors (the "Board") approved a $100 million common stock repurchase program to offset the impact of dilution associated with annual employee stock awards, of which $78 million remained available for use to purchase shares as of September 30, 2018 . During the nine months ended September 30, 2018 , the Company purchased $22 million of common stock pursuant to the program.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In October 2018, the Company entered into a purchase and sale agreement to sell approximately 2,900 net acres in the Sinor Nest (Lower Wilcox) field in South Texas to an unaffiliated third party for cash proceeds of $132 million , before normal closing adjustments . The sale of these assets is expected to result in a pretax gain of $45 million to $65 million . The transaction is expected to close during the fourth quarter, subject to the satisfaction of customary closing conditions. In October 2018, the Company entered into a Credit Agreement with a syndicate of financial institutions, primarily to extend the maturity of the Credit Facility from August 2020 to October 2023, while maintaining aggregate loan commitments of $1.5 billion . The Company accounted for the entry into the Credit Agreement as a modification of the prior agreement and capitalized the debt issuance costs along with those unamortized issuance costs that remained from the issuance of the prior agreement. As of September 30, 2018 , the Company had no outstanding borrowings under the Credit Facility.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Presentation	Presentation. In the opinion of management, the consolidated financial statements of the Company as of September 30, 2018 and for the three and nine months ended September 30, 2018 and 2017 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, 2017 . Certain reclassifications have been made to the 2017 financial statement and footnote amounts in order to conform to the 2018 presentation.
New accounting pronouncements	New accounting pronouncements. 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 accounting for lease expenses. This standard is effective for fiscal years beginning after December 15, 2018 and for interim periods beginning the following year. This ASU should be applied using a modified retrospective approach, and early adoption is permitted.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 and December 31, 2017 for each of the fair value hierarchy levels: Fair Value Measurement as of September 30, 2018 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 September 30, 2018 (in millions) Assets: Commodity derivatives $ — $ 1 $ — $ 1 Deferred compensation plan assets 90 — — 90 Total assets 90 1 — 91 Liabilities: Commodity derivatives — 552 — 552 Total liabilities — 552 — 552 Total recurring fair value measurements $ 90 $ (551 ) $ — $ (461 ) Fair Value Measurement as of December 31, 2017 Using Quoted Prices Significant Significant Fair value as of December 31, 2017 (in millions) Assets: Commodity derivatives $ — $ 11 $ — $ 11 Deferred compensation plan assets 95 — — 95 Total assets 95 11 — 106 Liabilities: Commodity derivatives — 255 — 255 Total liabilities — 255 — 255 Total recurring fair value measurements $ 95 $ (244 ) $ — $ (149 )
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 September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 Carrying Value Fair Value Carrying Value Fair Value (in millions) Commercial paper, corporate bonds and time deposits $ 750 $ 749 $ 1,279 $ 1,277 Current portion of long-term debt $ — $ — $ 449 $ 457 Long-term debt $ 2,286 $ 2,386 $ 2,283 $ 2,479
Cash and cash equivalents and investments	The following tables provide the components of the Company's cash and cash equivalents and investments as of September 30, 2018 and December 31, 2017 : September 30, 2018 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Deposits Total (in millions) Cash and cash equivalents $ 869 $ — $ — $ 50 $ 919 Short-term investments — 131 275 151 557 Long-term investments — — 193 — 193 $ 869 $ 131 $ 468 $ 201 $ 1,669 December 31, 2017 Consolidated Balance Sheet Location Cash Commercial Paper Corporate Bonds Time Total (in millions) Cash and cash equivalents $ 846 $ — $ — $ 50 $ 896 Short-term investments — 124 642 447 1,213 Long-term investments — — 66 — 66 $ 846 $ 124 $ 708 $ 497 $ 2,175

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 and the weighted average oil prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Brent swap contracts (a): Volume (Bbl) — 10,000 Price per Bbl — $ 70.00 Brent collar contracts with short puts (b): Volume (Bbl) — 5,000 Price per Bbl: Ceiling $ — $ 87.00 Floor $ — $ 75.00 Short put $ — $ 65.00 NYMEX collar contracts: Volume (Bbl) 3,000 — Price per Bbl: Ceiling $ 58.05 $ — Floor $ 45.00 $ — NYMEX collar contracts with short puts: Volume (Bbl) 159,000 55,000 Price per Bbl: Ceiling $ 57.62 $ 60.13 Floor $ 47.26 $ 52.27 Short put $ 37.23 $ 42.27 ____________________ (a) Subsequent to September 30, 2018 , the Company liquidated its Brent swap contracts for cash payments of $5 million . (b) Subsequent to September 30, 2018 , the Company entered into additional Brent collar contracts with short puts for 10,000 Bbls per day of 2019 production with a ceiling price of $91.36 per Bbl, a floor price of $75.00 per Bbl and a short put price of $65.00 per Bbl.
Schedule of NGL derivative volumes and weighted average prices	The following table sets forth the volumes per day associated with the Company's outstanding NGL derivative contracts as of September 30, 2018 and the weighted average NGL prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Ethane basis swap contracts (a): Volume (MMBtu) 6,920 6,920 Price differential ($/MMBtu) $ 1.60 $ 1.60 ____________________ (a) The ethane basis swap contracts reduce the price volatility of ethane forecasted for sale by the Company at Mont Belvieu, Texas-posted prices. The ethane 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. Subsequent to September 30, 2018 , the Company liquidated its ethane basis swap contracts for cash payments of $4 million .
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 September 30, 2018 and the weighted average gas prices for those contracts: 2018 Year Ending December 31, 2019 Fourth Quarter Swap contracts (a): Volume (MMBtu) 101,348 647 Price per MMBtu $ 3.00 $ 3.11 Collar contracts with short puts: Volume (MMBtu) 50,000 — Price per MMBtu: Ceiling $ 3.40 $ — Floor $ 2.75 $ — Short put $ 2.25 $ — Basis swap contracts: Permian Basin index swap volume (MMBtu) (b) 58,652 44,230 Price differential ($/MMBtu) $ (1.46 ) $ (1.46 ) Southern California index swap volume (MMBtu) (c) 66,522 84,932 Price differential ($/MMBtu) $ 0.50 $ 0.33 ____________________ (a) Subsequent to September 30, 2018 , the Company entered into additional swap contracts for 50,000 MMBtu per day of January through March 2019 production with an average fixed price of $3.24 per MMBtu. (b) The referenced basis swap contracts fix the basis differentials between the index price at which the Company sells its Permian Basin gas and the HH price used in swap contracts and collar contracts with short puts. (c) The referenced basis swap contracts fix the basis differentials between Permian Basin index prices and southern California index prices for Permian Basin gas forecasted for sale in Arizona and 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 September 30, 2018 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 $ 7 $ (6 ) $ 1 Commodity price derivatives Derivatives - noncurrent $ 1 $ (1 ) — $ 1 Liability Derivatives: Commodity price derivatives Derivatives - current $ 488 $ (6 ) $ 482 Commodity price derivatives Derivatives - noncurrent $ 71 $ (1 ) 70 $ 552 Fair Value of Derivative Instruments as of December 31, 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 $ 13 $ (2 ) $ 11 Commodity price derivatives Derivatives - noncurrent $ 3 $ (3 ) — $ 11 Liability Derivatives: Commodity price derivatives Derivatives - current $ 234 $ (2 ) $ 232 Commodity price derivatives Derivatives - noncurrent $ 26 $ (3 ) 23 $ 255
Schedule of derivative gains and losses recognized on statement of operations	The following table details the location of gains and losses recognized on the Company's derivative contracts in the accompanying consolidated statements of operations: Derivatives Not Designated as Hedging Instruments Location of Gain/(Loss) Recognized in Earnings on Derivatives Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Commodity price derivatives Derivative gains (losses), net $ (135 ) $ (133 ) $ (701 ) $ 154 Interest rate derivatives Derivative gains (losses), net — — — (1 ) Total $ (135 ) $ (133 ) $ (701 ) $ 153

Exploratory Costs (Tables)

Exploratory Costs (Tables)	9 Months Ended
	Sep. 30, 2018
Extractive Industries [Abstract]
Capitalized exploratory well and project activity	The following table reflects the Company's capitalized exploratory well and project activity during the three and nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in millions) Beginning capitalized exploratory well costs $ 575 $ 505 Additions to exploratory well costs pending the determination of proved reserves 607 1,820 Reclassification due to determination of proved reserves (554 ) (1,689 ) Disposition of assets (1 ) (1 ) Exploratory well costs charged to exploration and abandonment expense (1 ) (9 ) Ending capitalized exploratory well costs $ 626 $ 626
Capitalized exploratory costs and the number of projects for which exploratory costs have been capitalized	The following table provides an aging as of September 30, 2018 and December 31, 2017 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: September 30, 2018 December 31, 2017 (in millions, except well counts) Capitalized exploratory well costs that have been suspended: One year or less $ 614 $ 493 More than one year 12 12 $ 626 $ 505 Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year 7 7

Incentive Plans (Tables)

Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Compensation Related Costs [Abstract]
Schedule of share based incentive award activity	The following table summarizes the activity that occurred during the nine months ended September 30, 2018 for restricted stock awards and performance units issued by the Company: Restricted Stock Equity Awards Restricted Stock Liability Awards Performance Units Outstanding as of December 31, 2017 916,223 252,735 163,158 Awards granted 390,618 113,231 62,541 Awards forfeited (45,877 ) (19,164 ) (1,285 ) Awards vested (426,541 ) (131,496 ) (34,778 ) Outstanding as of September 30, 2018 834,423 215,306 189,636

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2018
Asset Retirement Obligation [Abstract]
Schedule of asset retirement obligations	The following table summarizes the Company's asset retirement obligation activity during the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Beginning asset retirement obligations $ 185 $ 294 $ 271 $ 297 New wells placed on production 1 — 2 2 Changes in estimates — — 2 7 Dispositions (10 ) — (89 ) (7 ) Liabilities settled (5 ) (7 ) (23 ) (21 ) Accretion of discount 3 5 11 14 Ending asset retirement obligations $ 174 $ 292 $ 174 $ 292

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Schedule of adoption of ASC 606	The adoption of ASC 606 as of January 1, 2018 had the following impact on the Company's results of operations for the three and nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 As Reported ASC 605 (Without Adoption of ASC 606) Effect of Change Higher (Lower) As Reported ASC 605 Effect of Change (in millions) (in millions) Revenues and other income: Oil and gas $ 1,317 $ 1,258 $ 59 $ 3,869 $ 3,713 $ 156 Costs and expenses: Oil and gas production $ 198 $ 139 $ 59 $ 654 $ 498 $ 156
Disaggregation of revenue	The following table provides information about disaggregated revenue from contracts with purchasers by product type: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in millions) Oil sales $ 1,033 $ 3,079 NGL sales 207 542 Gas sales 77 248 Total oil and gas sales 1,317 3,869 Sales of purchased oil 1,127 3,261 Sales of purchased gas 14 45 Total sales of purchased oil and gas 1,141 3,306 Total revenue derived from contracts with purchasers $ 2,458 $ 7,175

Interest and Other Income (Tabl

Interest and Other Income (Tables)	9 Months Ended
	Sep. 30, 2018
Interest and Other Income [Abstract]
Components of interest and other income	The following table provides the components of the Company's interest and other income for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Interest income $ 7 $ 9 $ 21 $ 25 Deferred compensation plan income 3 1 6 3 Other income — 2 7 3 Seismic data sales — — 5 — Production and sales tax refunds — 5 1 13 Total interest and other income $ 10 $ 17 $ 40 $ 44

Other Expense (Tables)

Other Expense (Tables)	9 Months Ended
	Sep. 30, 2018
Other Income and Expenses [Abstract]
Schedule of components of other expense	The following table provides the components of the Company's other expense for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Transportation commitment charges (a) $ 43 $ 45 $ 121 $ 127 Legal and environmental charges 6 2 18 9 Loss (income) from vertical integration services (b) (5 ) — 5 11 Asset divestiture related charges (c) 123 — 132 — Other 15 11 40 29 Total other expense $ 182 $ 58 $ 316 $ 176 ____________________ (a) Primarily represents firm transportation payments on excess pipeline capacity commitments. (b) Loss (income) 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 nine months ended September 30, 2018 , these vertical integration net margins included $49 million and $113 million , respectively, of revenues and $44 million and $118 million , respectively, of costs and expenses. For the same respective periods in 2017, these vertical integration net margins included $42 million and $84 million of revenues and $42 million and $95 million of costs and expenses.

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2018
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 nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Current tax provision $ (2 ) $ — $ (2 ) $ — Deferred tax benefit (provision) (116 ) 11 (186 ) (79 ) Income tax benefit (provision) $ (118 ) $ 11 $ (188 ) $ (79 )

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Reconciliation of earnings attributable to common stockholders, basic and diluted	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 nine months ended September 30, 2018 and 2017 : Three Months Ended Nine Months Ended 2018 2017 2018 2017 (in millions) Net income (loss) attributable to common stockholders $ 411 $ (23 ) $ 655 $ 168 Participating share-based earnings (2 ) — (3 ) (1 ) Basic and diluted net income (loss) attributable to common stockholders $ 409 $ (23 ) $ 652 $ 167

Organization and Nature of Op_2

Organization and Nature of Operations (Details) $ in Millions	1 Months Ended			9 Months Ended
	Oct. 31, 2018USD ($)a	Jul. 31, 2018USD ($)	Apr. 30, 2018USD ($)a	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Aug. 31, 2018USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from disposition of assets				$ 383	$ 347
Raton Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from disposition of assets		$ 79
West Panhandle field
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds, before normal closing adjustments						$ 201
Sinor Nest | Subsequent event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net acres | a	2,900
Proceeds from disposition of assets	$ 132
West Eagle Ford Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net acres | a			10,200
Proceeds from disposition of assets			$ 103

Divestitures (Details)

Divestitures (Details) T in Millions	1 Months Ended					3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)T	Jul. 31, 2018USD ($)	Jun. 30, 2018USD ($)	Apr. 30, 2018USD ($)a	Apr. 30, 2017USD ($)aBoe	Sep. 30, 2018USD ($)T	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)T	Sep. 30, 2017USD ($)	Aug. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Combinations [Abstract]
Purchased interest in sand reserves	$ 17,000,000
Sand Reserves, Processing Agreement, Volume | T	30					30		30
Sand Reserves, Supply Agreement Terms	15 years
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds								$ 383,000,000	$ 347,000,000
Gain on disposition of assets, net						$ 143,000,000	$ 0	226,000,000	205,000,000
Impairment of oil and gas properties						0	$ 0	77,000,000	$ 285,000,000
Divestiture related liabilities, current	$ 42,000,000					42,000,000		42,000,000
Divestiture related liabilities, noncurrent	68,000,000					68,000,000		68,000,000
Accounts payable - Due to affiliates	108,000,000					108,000,000		108,000,000			$ 108,000,000
Divestiture related liabilities											$ 0
Employee severance
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts payable - Due to affiliates	$ 10,000,000					10,000,000		10,000,000
West Eagle Ford Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net acres | a				10,200
Cash proceeds				$ 103,000,000
Gain on disposition of assets, net						75,000,000
Reduction of goodwill				$ 1,000,000
Raton Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds		$ 79,000,000
Gain on disposition of assets, net						2,000,000		2,000,000
Reduction of goodwill		$ 1,000,000
Impairment of oil and gas properties			$ 77,000,000
Divestiture charges						117,000,000		123,000,000
West Panhandle field
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposition of assets, net						146,000,000		146,000,000
Reduction of goodwill								1,000,000
Divestiture charges						$ 6,000,000		6,000,000
Cash proceeds, before normal closing adjustments										$ 201,000,000
Martin County region of the Permian Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net acres | a					20,500
Cash proceeds					$ 264,000,000
Gain on disposition of assets, net					194,000,000
Reduction of goodwill					$ 2,000,000
Net production (BOEPD) | Boe					1,500
Permian Basin
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds								75,000,000
Gain on disposition of assets, net								$ 12,000,000

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets:
Deferred compensation plan assets	$ 90	$ 95
Total assets	91	106
Liabilities:
Total liabilities	552	255
Total recurring fair value measurements	(461)	(149)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Deferred compensation plan assets	90	95
Total assets	90	95
Liabilities:
Total liabilities	0	0
Total recurring fair value measurements	90	95
Significant Other Observable Inputs (Level 2)
Assets:
Deferred compensation plan assets	0	0
Total assets	1	11
Liabilities:
Total liabilities	552	255
Total recurring fair value measurements	(551)	(244)
Significant Unobservable Inputs (Level 3)
Assets:
Deferred compensation plan assets	0	0
Total assets	0	0
Liabilities:
Total liabilities	0	0
Total recurring fair value measurements	0	0
Commodity derivatives
Assets:
Derivative assets	1	11
Liabilities:
Commodity derivatives	552	255
Commodity derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative assets	0	0
Liabilities:
Commodity derivatives	0	0
Commodity derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivative assets	1	11
Liabilities:
Commodity derivatives	552	255
Commodity derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivative assets	0	0
Liabilities:
Commodity derivatives	$ 0	$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2018USD ($)	Mar. 31, 2017USD ($)$ / MMBTU$ / bbl	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties			$ 0	$ 0	$ 77	$ 285
Raton Basin
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties	$ 77
Raton
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of oil and gas properties		$ 285
Estimated fair value		$ 186
Management oil price outlook per barrel | $ / bbl		53.65
Management gas price outlook per millions of BTU | $ / MMBTU		3
Cash flow discount rate | Raton
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate		0.10

Fair Value Measurements (Sche_2

Fair Value Measurements (Schedule Of Carrying Values And Financial Instruments Not Carried At Fair Value) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long-term debt	$ 0	$ 449
Long-term debt	2,286	2,283
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial paper, corporate bonds and time deposits	750	1,279
Current portion of long-term debt	0	449
Long-term debt	2,286	2,283
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial paper, corporate bonds and time deposits	749	1,277
Current portion of long-term debt	0	457
Long-term debt	$ 2,386	$ 2,479

Fair Value Measurements (Sche_3

Fair Value Measurements (Schedule of Cash and Cash Equivalents and Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents	$ 919	$ 896	$ 636	$ 1,118
Short-term investments	557	1,213
Long-term investments	193	66
Total cash and cash equivalents and investments	1,669	2,175
Cash
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents	869	846
Short-term investments	0	0
Long-term investments	0	0
Total cash and cash equivalents and investments	869	846
Commercial Paper
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents	0	0
Short-term investments	131	124
Long-term investments	0	0
Total cash and cash equivalents and investments	131	124
Corporate Bonds
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents	0	0
Short-term investments	275	642
Long-term investments	193	66
Total cash and cash equivalents and investments	468	708
Time Deposits
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents	50	50
Short-term investments	151	447
Long-term investments	0	0
Total cash and cash equivalents and investments	$ 201	$ 497

Derivative Financial Instrume_3

Derivative Financial Instruments (Schedule Of Oil Derivative Contracts Volume And Weighted Average Prices) (Details) $ in Millions	1 Months Ended
	Nov. 07, 2018USD ($)	Oct. 01, 2018bbl / d$ / bbl	Sep. 30, 2018bbl / d$ / bbl
Oil contracts | Brent swap contracts for Q4
Derivative [Line Items]
Volume, barrels per day | bbl / d			0
Oil contracts | Brent swap ocntracts for next year
Derivative [Line Items]
Volume, barrels per day | bbl / d			10,000
Oil contracts | Brent collar contracts with short puts for Q4
Derivative [Line Items]
Volume, barrels per day | bbl / d			0
Oil contracts | Brent collar contracts with short puts for Q4 | Subsequent event
Derivative [Line Items]
Volume, barrels per day | bbl / d		10,000
Oil contracts | Brent collar contracts with short puts for next year
Derivative [Line Items]
Volume, barrels per day | bbl / d			5,000
Oil contracts | Collar contract for Q4
Derivative [Line Items]
Volume, barrels per day | bbl / d			3,000
Oil contracts | Collar Contracts for next year
Derivative [Line Items]
Volume, barrels per day | bbl / d			0
Oil contracts | Collar contracts with short puts for Q4
Derivative [Line Items]
Volume, barrels per day | bbl / d			159,000
Oil contracts | Collar contracts with short puts for next year
Derivative [Line Items]
Volume, barrels per day | bbl / d			55,000
Oil contracts, price per bbl | Brent swap contracts for Q4
Derivative [Line Items]
Price per MMBtu in usd			0
Oil contracts, price per bbl | Brent swap ocntracts for next year
Derivative [Line Items]
Price per MMBtu in usd			70
Oil contracts, price per bbl | Brent collar contracts with short puts for Q4
Derivative [Line Items]
Ceiling, price per barrel			0
Floor, price per barrel			0
Short put, price per barrel			0
Oil contracts, price per bbl | Brent collar contracts with short puts for next year
Derivative [Line Items]
Ceiling, price per barrel			87
Floor, price per barrel			75
Short put, price per barrel			65
Oil contracts, price per bbl | Brent collar contracts with short puts for next year | Subsequent event
Derivative [Line Items]
Ceiling, price per barrel		91.36
Floor, price per barrel		75
Short put, price per barrel		65
Oil contracts, price per bbl | Collar contract for Q4
Derivative [Line Items]
Ceiling, price per barrel			58.05
Floor, price per barrel			45
Oil contracts, price per bbl | Collar Contracts for next year
Derivative [Line Items]
Ceiling, price per barrel			0
Floor, price per barrel			0
Oil contracts, price per bbl | Collar contracts with short puts for Q4
Derivative [Line Items]
Ceiling, price per barrel			57.62
Floor, price per barrel			47.26
Short put, price per barrel			37.23
Oil contracts, price per bbl | Collar contracts with short puts for next year
Derivative [Line Items]
Ceiling, price per barrel			60.13
Floor, price per barrel			52.27
Short put, price per barrel			42.27
Brent [Member] | Subsequent event
Derivative [Line Items]
Derivative, Cash Paid for Liquidation | $	$ 5

Derivative Financial Instrume_4

Derivative Financial Instruments (Schedule of NGL Derivative Contracts Volume and Weighted Average Prices) (Details) - Ethane $ in Millions	1 Months Ended
	Nov. 07, 2018USD ($)	Sep. 30, 2018bbl / dMMBTU / d$ / MMBTU
Subsequent event
Derivative [Line Items]
Derivative, Cash Paid for Liquidation | $	$ 4
NGL contract, MMBtu Equivalent
Derivative [Line Items]
Volume, barrels per day		6,920
NGL contract, MMBtu Equivalent | Basis swap contracts for Q4
Derivative [Line Items]
Volume, barrels per day		6,920
NGL contract, MMBtu Equivalent | Basis swap contracts for next year
Derivative [Line Items]
Volume, barrels per day		6,920
NGL contract, price per MMBtu Equivalent | Basis swap contracts for Q4
Derivative [Line Items]
Price differential, dollars per barrel | $ / MMBTU		1.60
NGL contract, price per MMBtu Equivalent | Basis swap contracts for next year
Derivative [Line Items]
Price differential, dollars per barrel | $ / MMBTU		1.60
NGL contract, in BBLS
Derivative [Line Items]
Volume, barrels per day | bbl / d		2,500

Derivative Financial Instrume_5

Derivative Financial Instruments (Schedule of Gas Derivative Contracts Volume and Weighted Average Prices) (Details)	Apr. 30, 2019MMBTU / d$ / MMBTU	Nov. 07, 2018MMBTU / d$ / MMBTU	Sep. 30, 2018MMBTU / d$ / MMBTU
Swap contracts for Q4 | Gas contracts, in MMBTU
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			101,348
Swap contracts for Q4 | Gas contracts, in MMBTU | Subsequent event
Derivative [Line Items]
Volume, barrels per day | MMBTU / d	50,000
Swap contracts for Q4 | Gas contracts, price per MMBTU
Derivative [Line Items]
Price per MMBtu in usd			3
Swap contracts for Q4 | Gas contracts, price per MMBTU | Subsequent event
Derivative [Line Items]
Price per MMBtu in usd	3.24
Swap contracts for next year | Gas contracts, in MMBTU
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			647
Swap contracts for next year | Gas contracts, in MMBTU | Subsequent event
Derivative [Line Items]
Volume, barrels per day | MMBTU / d		4,500
Swap contracts for next year | Gas contracts, price per MMBTU
Derivative [Line Items]
Price per MMBtu in usd			3.11
Swap contracts for next year | Gas contracts, price per MMBTU | Subsequent event
Derivative [Line Items]
Price per MMBtu in usd		1.58
Collar contracts with short puts for Q4 | Gas contracts, in MMBTU
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			50,000
Collar contracts with short puts for Q4 | Gas contracts, price per MMBTU
Derivative [Line Items]
Ceiling, price per barrel			3.40
Floor, price per barrel			2.75
Short put, price per barrel			2.25
Collar contracts with short puts for next year | Gas contracts, in MMBTU
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			0
Collar contracts with short puts for next year | Gas contracts, price per MMBTU
Derivative [Line Items]
Ceiling, price per barrel			0
Floor, price per barrel			0
Short put, price per barrel			0
Basis swap contracts for Q4 | Gas contracts, in MMBTU | Permian Basin
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			58,652
Basis swap contracts for Q4 | Gas contracts, in MMBTU | Southern California
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			66,522
Basis swap contracts for Q4 | Gas contracts, price per MMBTU | Permian Basin
Derivative [Line Items]
Price differential, dollars per barrel			(1.46)
Basis swap contracts for Q4 | Gas contracts, price per MMBTU | Southern California
Derivative [Line Items]
Price differential, dollars per barrel			0.50
Basis swap contracts for next year | Gas contracts, in MMBTU | Permian Basin
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			44,230
Basis swap contracts for next year | Gas contracts, in MMBTU | Southern California
Derivative [Line Items]
Volume, barrels per day | MMBTU / d			84,932
Basis swap contracts for next year | Gas contracts, price per MMBTU | Permian Basin
Derivative [Line Items]
Price differential, dollars per barrel			(1.46)
Basis swap contracts for next year | Gas contracts, price per MMBTU | Southern California
Derivative [Line Items]
Price differential, dollars per barrel			0.33

Derivative Financial Instrume_6

Derivative Financial Instruments (Schedule Of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives - current	$ 1	$ 11
Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - current	482	232
Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - noncurrent	70	23
Derivatives not designated as hedging instruments
Derivative [Line Items]
Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives	1	11
Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives	552	255
Derivatives not designated as hedging instruments | Commodity price derivatives | Derivatives - current
Derivative [Line Items]
Asset Derivatives, Fair Value	7	13
Gross Amounts Offset in the Consolidated Balance Sheet, Assets Derivatives	(6)	(2)
Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives - current	1	11
Liability Derivatives, Fair Value	488	234
Gross Amounts Offset in the Consolidated Balance Sheet. Liabilities Derivatives	(6)	(2)
Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - current	482	232
Derivatives not designated as hedging instruments | Commodity price derivatives | Derivatives - noncurrent
Derivative [Line Items]
Asset Derivatives, Fair Value	1	3
Gross Amounts Offset in the Consolidated Balance Sheet, Assets Derivatives	(1)	(3)
Net Fair Value Presented in the Consolidated Balance Sheet, Asset Derivatives - noncurrent	0	0
Liability Derivatives, Fair Value	71	26
Gross Amounts Offset in the Consolidated Balance Sheet. Liabilities Derivatives	(1)	(3)
Net Fair Value Presented in the Consolidated Balance Sheet, Liabilities Derivatives - noncurrent	$ 70	$ 23

Derivative Financial Instrume_7

Derivative Financial Instruments (Schedule Of Derivative Obligations Under Terminated Hedge Arrangements) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Derivative gains (losses), net	$ (135)	$ (133)	$ (701)	$ 153
Derivative gains (losses), net | Commodity price derivatives
Derivative [Line Items]
Derivative gains (losses), net	(135)	(133)	(701)	154
Derivative gains (losses), net | Interest rate derivatives
Derivative [Line Items]
Derivative gains (losses), net	$ 0	$ 0	$ 0	$ (1)

Exploratory Costs (Schedule Of

Exploratory Costs (Schedule Of Capitalized Exploratory Well And Project Activity) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Beginning capitalized exploratory well costs	$ 575	$ 505
Additions to exploratory well costs pending the determination of proved reserves	607	1,820
Reclassification due to determination of proved reserves	(554)	(1,689)
Disposition of assets	(1)	(1)
Exploratory well costs charged to exploration and abandonment expense	(1)	(9)
Ending capitalized exploratory well costs	$ 626	$ 626

Exploratory Costs (Capitalized

Exploratory Costs (Capitalized Exploratory Costs And the Number Of Projects For Which Exploratory Costs Have Been Capitalized) (Details) $ in Millions	Sep. 30, 2018USD ($)Well	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)Well
Capitalized exploratory well costs that have been suspended:
One year or less	$ 614		$ 493
More than one year	12		12
Total	$ 626	$ 575	$ 505
Number of wells or projects with exploratory well costs that have been suspended for a period greater than one year | Well	7		7

Long-term Debt (Details)

Long-term Debt (Details) - USD ($)	May 01, 2018	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Aggregate loan commitments			$ 1,500,000,000
Outstanding borrowing			0
Repayments			$ 450,000,000	$ 485,000,000
6.65% Senior notes
Debt Instrument [Line Items]
Stated interest rate				6.65%
Repayments		$ 485,000,000
6.875% Senior notes
Debt Instrument [Line Items]
Stated interest rate	6.875%
Repayments	$ 450,000,000

Incentive Plans Incentive Plans

Incentive Plans Incentive Plans (Stock-based compensation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Compensation Related Costs [Abstract]
Stock-based compensation expense	$ 27	$ 21	$ 79	$ 78
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	111		$ 111
Remaining vesting period			3 years
Restricted Stock Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	24		$ 24
Restricted Stock Liability Awards | Affiliates
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Due to affiliates	$ 13		$ 13		$ 20
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding, shares	131,630		131,630		138,493

Incentive Plans Incentive Pla_2

Incentive Plans Incentive Plans (Share Based Incentive Award Activity) (Details) - shares	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Restricted Stock Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance outstanding, shares	916,223
Awards granted, shares	390,618
Awards forfeited, shares	(45,877)
Awards vested, shares	(426,541)
Ending balance outstanding, shares	834,423
Restricted Stock Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance outstanding, shares	252,735
Awards granted, shares	113,231
Awards forfeited, shares	(19,164)
Awards vested, shares	(131,496)
Ending balance outstanding, shares	215,306
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance outstanding, shares	163,158
Awards granted, shares	62,541
Awards forfeited, shares	(1,285)
Awards vested, shares	(34,778)
Ending balance outstanding, shares	189,636
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Stock options outstanding, shares	131,630	138,493
Exercise of stock options, shares	(6,863)

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning asset retirement obligations	$ 185	$ 294	$ 271	$ 297
New wells placed on production	1	0	2	2
Changes in estimates	0	0	2	7
Dispositions	10	0	89	7
Liabilities settled	(5)	(7)	(23)	(21)
Accretion of discount	3	5	11	14
Ending asset retirement obligations	174	$ 292	174	$ 292
Asset retirement obligations, current portions	$ 28		$ 28		$ 41

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Loss Contingencies [Line Items]
Operating lease term		20 years
Annual base rent	$ 33,000
Capitalized construction costs	170,000
TCEQ enforcement action | Maximum
Loss Contingencies [Line Items]
Monetary sanctions	$ 525

Revenue Recognition (Schedule o

Revenue Recognition (Schedule of Adoption of ASC 606) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 2,458		$ 7,175
Oil and gas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	1,317	$ 855	3,869	$ 2,433
Costs and expenses	198	$ 152	654	$ 440
Oil and gas | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	1,317		3,869
Costs and expenses	198		654
Oil and gas | ASC 605 (Without Adoption of ASC 606) | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	1,258		3,713
Costs and expenses	139		498
Oil and gas | Effect of Change Higher (Lower) | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	59		156
Costs and expenses	$ 59		$ 156

Revenue Recognition (Disaggrega

Revenue Recognition (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	$ 2,458	$ 7,175
Oil sales
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	1,033	3,079
NGL sales
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	207	542
Gas sales
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	77	248
Total oil and gas sales
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	1,317	3,869
Sales of purchased oil
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	1,127	3,261
Sales of purchased gas
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	14	45
Total sales of purchased oil and gas
Disaggregation of Revenue [Line Items]
Total revenue derived from contracts with purchasers	$ 1,141	$ 3,306

Revenue Recognition (Narrative)

Revenue Recognition (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Timing of satisfaction of performance obligations	The majority of the Company's product sale commitments are short-term in nature with a contract term of one year or less. The Company typically satisfies its performance obligations upon transfer of control as described above in Disaggregated revenue from contracts with purchasers and records the related revenue in the month production is delivered to the purchaser. Settlement statements for sales of oil, NGLs and gas and sales of purchased oil and gas may not be received for 30 to 60 days after the date the volumes are delivered, and as a result, the Company is required to estimate the amount of volumes delivered to the purchaser and the price that will be received for the sale of the product.
Accounts receivable balance representing amounts due or billable	$ 806	$ 594

Interest and Other Income (Comp

Interest and Other Income (Components Of Interest And Other Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest and Other Income [Abstract]
Interest income	$ 7	$ 9	$ 21	$ 25
Deferred compensation plan income	3	1	6	3
Other income	0	2	7	3
Seismic data sales	0	0	5	0
Production and sales tax refunds	0	5	1	13
Total interest and other income	$ 10	$ 17	$ 40	$ 44

Other Expense (Schedule Of Comp

Other Expense (Schedule Of Components Of Other Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Income and Expenses [Abstract]
Transportation commitment charges	$ 43	$ 45	$ 121	$ 127
Legal and environmental charges	6	2	18	9
Loss from vertical integration services	(5)	0	5	11
Asset divestiture related charges (c)	123	0	132	0
Other	15	11	40	29
Total other expense	182	58	316	176
Vertical integration net margins, revenue	49	42	113	84
Vertical integration net margins, costs and expenses	$ 44	$ 42	$ 118	$ 95

Income Taxes (Income tax (provi

Income Taxes (Income tax (provisions) benefits attributable to income from continuing operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Current tax provision	$ 2	$ 0	$ 2	$ 0
Deferred income taxes	(116)	11	(186)	(79)
Income tax benefit (provision)	$ 118	$ (11)	$ 188	$ 79

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	22.00%	34.00%		32.00%
Recognizing excess tax benefits associated with the adoption of ASU 2016-09			$ 8
Unrecognized Tax Benefits	$ 135		$ 135		$ 124

Net Income (Loss) Per Share (Re

Net Income (Loss) Per Share (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to common stockholders	$ 411	$ (23)	$ 655	$ 168
Participating share-based earnings	(2)	0	(3)	(1)
Basic income (loss) from continuing operations attributable to common stockholders	409	(23)	652	167
Diluted income (loss) from continuing operations attributable to common stockholders	$ 409	$ (23)	$ 652	$ 167

Net Income (Loss) Per Share (Na

Net Income (Loss) Per Share (Narrative) (Details) - USD ($) shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Feb. 28, 2018
Equity, Class of Treasury Stock [Line Items]
Basic and diluted weighted average shares outstanding	171	170	171	170
Common stock purchased			$ 51,000,000
Common stock repurchase program
Equity, Class of Treasury Stock [Line Items]
Authorized amount					$ 100,000,000
Remaining authorized amount	$ 78,000,000		78,000,000
Common stock purchased			$ 22,000,000

Subsequent Events (Details)

Subsequent Events (Details)	1 Months Ended	9 Months Ended
	Oct. 31, 2018USD ($)a	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Subsequent Event [Line Items]
Cash proceeds		$ 383,000,000	$ 347,000,000
Aggregate loan commitments		$ 1,500,000,000
Minimum | Forecast | Sinor Nest
Subsequent Event [Line Items]
Gain on disposal	$ 45,000,000
Maximum | Forecast | Sinor Nest
Subsequent Event [Line Items]
Gain on disposal	65,000,000
Subsequent event
Subsequent Event [Line Items]
Aggregate loan commitments	$ 1,500,000,000
Subsequent event | Sinor Nest
Subsequent Event [Line Items]
Net acres | a	2,900
Cash proceeds	$ 132,000,000