Cobalt International Energy 10-Q 2 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Jun. 30, 2016shares
Document And Entity Information [Abstract]
Entity Registrant Name	Cobalt International Energy, Inc.
Entity Central Index Key	1,471,261
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Trading Symbol	CIE
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	414,154,631
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 131,661	$ 71,593
Restricted cash and cash equivalents and investments	252,200	252,950
Joint interest and other receivables	48,932	54,709
Prepaid expenses and other current assets	57,562	43,881
Inventory	13,128	26,113
Short-term investments	440,866	885,994
Current assets held for sale	1,873,514	1,811,051
Total current assets	2,817,863	3,146,291
Property, plant, and equipment:
Oil and gas properties, successful efforts method of accounting, net of accumulated depletion of $6,574 and $0, as of June 30, 2016 and December 31, 2015, respectively	1,001,526	893,734
Other property and equipment, net of accumulated depreciation and amortization of $7,533 and $6,647, as of June 30, 2016 and December 31, 2015, respectively	4,748	2,202
Total property, plant, and equipment, net	1,006,274	895,936
Long-term restricted funds	9,044
Other assets	8,831	18,992
Total assets	3,842,012	4,061,219
Current liabilities:
Trade and other accounts payable	24,350	856
Accrued liabilities	138,165	126,323
Deferred Angola sales proceeds	250,000	250,000
Current liabilities held for sale	196,707	250,839
Total current liabilities	609,222	628,018
Long-term debt	2,030,721	1,981,895
Asset retirement obligations	3,371	3,167
Other long-term liabilities	1,897	2,002
Total long-term liabilities	2,035,989	1,987,064
Stockholders’ Equity:
Common stock, $0.01 par value per share; 2,000,000,000 shares authorized, 410,054,961 and 408,740,182 issued and outstanding as of June 30, 2016 and December 31, 2015, respectively	4,101	4,088
Additional paid-in capital	4,166,910	4,164,097
Accumulated deficit	(2,974,210)	(2,722,048)
Total stockholders’ equity	1,196,801	1,446,137
Total liabilities and stockholders’ equity	$ 3,842,012	$ 4,061,219

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Oil and gas properties, successful efforts method of accounting, accumulated depletion (in dollars)	$ 6,574	$ 0
Other property and equipment, accumulated depreciation and amortization (in dollars)	$ 7,533	$ 6,647
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	410,054,961	408,740,182
Common stock, shares outstanding	410,054,961	408,740,182

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Oil and gas revenue:
Oil sales	$ 3,077,000		$ 4,688,000
Natural gas sales	40,000		65,000
Natural gas liquids sales	56,000		56,000
Total revenue	3,173,000		4,809,000
Operating costs and expenses:
Seismic and exploration	6,335,000	$ 11,267,000	5,081,000	$ 25,334,000
Dry hole expense and impairment	157,492,000	7,533,000	153,515,000	27,430,000
Lease operating expense	1,703,000		2,658,000
General and administrative	19,174,000	20,437,000	38,311,000	38,167,000
Accretion expense	102,000		204,000
Depreciation and amortization	4,290,000	367,000	7,459,000	779,000
Total operating costs and expenses	189,096,000	39,604,000	207,228,000	91,710,000
Operating income (loss)	(185,923,000)	(39,604,000)	(202,419,000)	(91,710,000)
Other income (expense):
Gain on sale of assets		2,625,000		2,625,000
Interest income	1,453,000	1,451,000	2,791,000	3,111,000
Interest expense	(15,975,000)	(17,841,000)	(31,616,000)	(37,861,000)
Total other income (expense)	(14,522,000)	(13,765,000)	(28,825,000)	(32,125,000)
Net income (loss) from continuing operations before income tax	(200,445,000)	(53,369,000)	(231,244,000)	(123,835,000)
Income tax expense	0		0
Net income (loss) from continuing operations	(200,445,000)	(53,369,000)	(231,244,000)	(123,835,000)
Net income (loss) from discontinued operations, net of income tax	(5,104,000)	(13,441,000)	(20,918,000)	(24,593,000)
Net income (loss)	$ (205,549,000)	$ (66,810,000)	$ (252,162,000)	$ (148,428,000)
Basic and diluted income (loss) per share from continuing operations	$ (0.49)	$ (0.13)	$ (0.56)	$ (0.30)
Basic and diluted income (loss) per share from discontinued operations	(0.01)	(0.03)	(0.05)	(0.06)
Basic and diluted income (loss) per share	$ (0.50)	$ (0.16)	$ (0.61)	$ (0.36)
Basic and diluted weighted average common shares outstanding	409,920,869	408,521,844	409,590,679	408,515,037

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Changes in Stockholders' Equity - 6 months ended Jun. 30, 2016 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2015	$ 1,446,137	$ 4,088	$ 4,164,097	$ (2,722,048)
Equity based compensation	2,826		2,826
Common stock issued for restricted stock and stock options		13	(13)
Net income (loss)	(252,162)			(252,162)
Balance at Jun. 30, 2016	$ 1,196,801	$ 4,101	$ 4,166,910	$ (2,974,210)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows provided from operating activities
Net income (loss)	$ (252,162)	$ (148,428)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	7,459	779
Gain on the sale of assets		(2,625)
Accretion expense	204
Loss from discontinued operations	20,918	24,593
Dry hole expense and impairment of unproved properties	153,515	27,430
Equity based compensation	2,826	12,981
Amortization of premium (accretion of discount) on investments	765	8,915
Amortization of debt discount and debt issuance costs	52,420	44,040
Changes in operating assets and liabilities:
Joint interest and other receivables	5,777	(36,751)
Inventory	12,962	7,211
Prepaid expense and other current assets	(13,681)	(20,826)
Deferred charges and other	6,566	(12,451)
Trade and other accounts payable	12,867	8,088
Accrued liabilities and other	(8,844)	(35,228)
Net cash provided by (used in) operating activities—continuing operations	1,592	(122,272)
Net cash provided by (used in) operating activities—discontinued operations	(53,029)	(19,259)
Net cash provided by (used in) operating activities	(51,437)	(141,531)
Cash flows from investing activities
Capital expenditures for other property and equipment	(3,432)	(188)
Exploratory wells drilling in process	(236,651)	(130,534)
Change in restricted funds	(8,247)	(48,249)
Proceeds from maturity of investment securities	1,166,266	909,569
Purchase of investment securities	(639,556)	(519,867)
Net cash provided by (used in) investing activities—continuing operations	278,380	210,731
Net cash provided by (used in) investing activities—discontinued operations	(166,875)	(173,806)
Net cash provided by (used in) investing activities	111,505	36,925
Cash flows from financing activities
Payment of debt issuance costs		(4,025)
Net cash provided by (used in) financing activities		(4,025)
Net increase (decrease) in cash and cash equivalents	60,068	(108,631)
Cash and cash equivalents, beginning of period	71,593	246,705
Cash and cash equivalents, end of period	131,661	138,074
Cash paid for interest	39,495	38,426
Non-cash disclosures
Changes in accrued capital expenditures	13,986	(54,135)
Transfer of investment securities to and from restricted funds	$ 82,348	$ 46,049

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies General Cobalt International Energy, Inc. (the “Company”) is an independent exploration and production company with operations in the deepwater U.S. Gulf of Mexico and offshore Angola and Gabon in West Africa. On August 22, 2015, Cobalt International Energy Angola Ltd., a wholly-owned subsidiary of the Company, executed a purchase and sale agreement with Sociedade Nacional de Combustíveis de Angola—Empresa Pública (“Sonangol”) for the sale by the Company to Sonangol of the entire issued and outstanding share capital of its indirect wholly-owned subsidiaries CIE Angola Block 20 Ltd. and CIE Angola Block 21 Ltd., which respectively hold the Company’s 40% working interest in each of Block 20 and Block 21 offshore Angola (the “Angola Transaction”). On July 26, 2016, the Company’s Chief Executive Officer met with Sonangol’s Chairwoman of the Board of Directors Isabel dos Santos and members of her executive team in Luanda, Angola to discuss the status of the Angolan Transaction. At this meeting, it was jointly agreed with Sonangol that the Company would market its working interests in Blocks 20 and 21 for sale by the Company to a third party other than Sonangol. On August 1, 2016, the Company received a letter from Chairwoman Isabel dos Santos confirming Sonangol’s support of such marketing and sale process. The Company therefore believes that it is unlikely that the Angola Transaction will close pursuant to the terms of the Purchase and Sale Agreement and believe that it is likely that the Purchase and Sale Agreement will automatically terminate on August 22, 2016. In such a case, the Purchase and Sale Agreement provides that the parties are to be restituted in order to put them in their original positions as if no agreement had been executed. The Company plans to work with Sonangol to understand and agree on the financial and operational implications of this provision. With respect to the marketing of its Angolan assets, the Company intends to immediately commence the marketing and sale process. On February 29, 2016, the Company relinquished its working interest in Block 9. The Company’s working interests in Blocks 20 and 21 offshore Angola have been classified as “held for sale” on the consolidated balance sheet. The results of operations associated with Blocks 9, 20 and 21 offshore Angola have been presented as discontinued operations in the accompanying consolidated statement of operations. Historically, the Company’s Angolan subsidiaries constituted a significant portion of its West Africa segment. The Company’s operations in Gabon, which are deemed immaterial, have been combined with its United States segment and are reported as one segment. The terms “Company,” “Cobalt,” “we,” “us,” “our,” “ours,” and similar terms refer to Cobalt International Energy, Inc. unless the context indicates otherwise. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the financial statements of Cobalt International Energy, Inc. and all of its wholly-owned subsidiaries. All significant intercompany transactions and amounts have been eliminated for all periods presented. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) for interim financial information and the appropriate rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, the condensed consolidated financial statements do not include all of the information and footnote disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for interim periods are not necessarily indicative of the results that may be presented for the entire year. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. Correction of Immaterial Errors The accompanying unaudited condensed financial statements for the six months ended June 30, 2016 include a reduction of impairment charges related to the Heidelberg field totaling approximately $8.5 million related to the prior year. The amounts were not deemed material with respect to such prior year or the anticipated results and the trend of earnings for fiscal year 2016. Recently Issued Accounting Standards In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (“ASU 2016-02”), Leases (Subtopic 842). Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, unlike current GAAP, which requires only capital leases to be recognized on the balance sheet, ASU 2016-02 will require both types of leases to be recognized on the balance sheet. ASU 2016-02 also will require disclosures to help investors and other financial statement users to better understand the amount, timing and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. ASU 2016-02 does not apply for leases for oil and gas properties, but does apply to equipment used to explore and develop oil and gas resources. The Company currently does not have any leases classified as financing leases. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018 and is to be applied using the modified retrospective approach. The Company has not yet fully determined or quantified the effect ASU 2016-02 will have on the Company’s financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09 (“ASU 2016-09”), Compensation – Stock Compensation (Subtopic 718). The objective of ASU 2016-09 is for simplification involving several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016 and early adoption is permitted. The Company has not yet fully determined or quantified the effect ASU 2016-09 will have on the Company’s financial statements. In May 2016, the FASB issued Accounting Standards Update No. 2016-11 (“ASU 2016-11”), Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting. The guidance requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. The Company is required to adopt the new standards in the first quarter of 2018 using one of two retrospective application methods. The Company is continuing to evaluate the provisions of these ASUs, and has not determined the impact these standards may have on its consolidated financial statements and related disclosures or decided upon the method of adoption. In April 2015, Financial Accounting Standards Board (FASB) amended Accounting Standard Codification Subtopic No. 835-30, Interest—Imputation of Interest (the “ASC Subtopic 835-30”). The amendments require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments. The amendments under ASC Subtopic 835-30 are effective for financial statements issued for fiscal years beginning after December 15, 2015 and interim periods within those fiscal years. The adoption of ASU 2015-03 resulted in $32.9 million of unamortized debt issuance costs reclassified from long-term assets to a reduction in long-term liabilities as of December 31, 2015. In July 2015, the FASB issued Accounting Standards Update (ASU) 2015-11, "Accounting for Inventory" (ASU 2015-11), which requires entities to measure most inventory at lower of cost or net realizable value. ASU 2015-11 defines net realizable value as "the estimated selling prices in the ordinary course of business, less reasonably predictable cost of completion, disposal and transportation." ASU 2015-11 is effective prospectively for interim and annual periods beginning after December 15, 2016. The Company adopted the amendments to ASC 2015-11 on January 1, 2016. The adoption of ASC 2015-11 did not have material impact on the Company’s financial statements. In August 2014, the FASB issued a new standard related to the disclosure of uncertainties about an entity's ability to continue as a going concern (ASU 2014-15). The new standard will explicitly require management to assess an entity's ability to continue as a going concern every reporting period and to provide related footnote disclosures in certain circumstances. The new standard will be effective for all entities in the first annual period ending after December 15, 2016, with early adoption permitted. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09 (“ASU 2014-09”), Summary and Amendments That Create Revenue from Contracts and Customers (Subtopic 606). ASU 2014-09 amends and replaces current revenue recognition requirements, including most industry-specific guidance. The revised guidance establishes a five step approach to be utilized in determining when, and if, revenue should be recognized. ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2017. Upon application, an entity may elect one of two methods, either restatement of prior periods presented or recording a cumulative adjustment in the initial period of application. The Company has not determined the effect ASU 2014-09 will have on the recognition of its revenue, if any, nor has the Company determined the method the Company will utilize upon adoption, which would be in the first quarter of 2018. Use of Estimates The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates made by the Company include (i) accruals related to expenses, (ii) assumptions used in estimating fair value of equity based awards and the fair value of the liability component of the convertible senior notes and (iii) assumptions used in impairment testing. Although the Company believes these estimates are reasonable, actual results could differ from these estimates. Investments The Company’s policy on accounting for its investments, which consist entirely of debt securities, is based on the accounting guidance relating to “ Accounting for Certain Investments in Debt and Equity Securities See Note 5—Investments Investments are considered to be impaired when a decline in fair value is determined to be other-than-temporary. The Company conducts a regular assessment of its debt securities with unrealized losses to determine whether securities have other-than-temporary impairment (“OTTI”). This assessment considers, among other factors, the nature of the securities, credit rating or financial condition of the issuer, the extent and duration of the unrealized loss, market conditions and whether the Company intends to sell or whether it is more likely than not that the Company will be required to sell the debt securities. As of June 30, 2016 and December 31, 2015, the Company has no OTTI in its debt securities. Property, Plant, and Equipment The Company uses the “successful efforts” method of accounting for its oil and gas properties. Acquisition costs for unproved leasehold properties and costs of drilling exploration wells are capitalized pending determination of whether proved reserves can be attributed to the areas as a result of drilling those wells. Under the successful efforts method of accounting, proved leasehold costs are capitalized and amortized over the proved developed and undeveloped reserves on a units-of-production basis. Successful drilling costs, costs of development and developmental dry holes are capitalized and amortized over the proved developed reserves on a units-of-production basis. When circumstances indicate that proved oil and gas properties may be impaired, the Company compares expected undiscounted future cash flows at a depreciation, depletion and amortization group level to the unamortized capitalized cost of the asset. If the expected undiscounted future cash flows, based on the Company's estimate of future crude oil and natural gas prices, operating costs, anticipated production from proved reserves and other relevant data, are lower than the unamortized capitalized cost, the capitalized cost is reduced to fair value. Fair value is generally calculated using the Income Approach described in the Fair Value Measurement Topic of the ASC. Significant unproved leasehold costs are capitalized and are not amortized, pending an evaluation of their exploration potential. Unproved leasehold costs are assessed periodically to determine if an impairment of the cost of individual properties has occurred. Factors taken into account for impairment analysis include results of the technical studies conducted, lease terms and management’s future exploration plans. The cost of impairment is charged to expense in the period in which it occurs. Costs incurred for exploration dry holes, geological and geophysical work (including the cost of seismic data), and delay rentals are charged to expense as incurred. Costs of other property and equipment are depreciated on a straight-line basis based on their respective useful lives. Asset Retirement Obligation The Company expects to have significant obligations under its lease agreements and federal regulation to remove its equipment and restore land or seabed at the end of oil and natural gas production operations. These asset retirement obligations (“ARO”) are primarily associated with plugging and abandoning wells and removing and disposing of offshore oil and natural gas platforms. Estimating the future restoration and removal cost is difficult and requires the Company to make estimates and judgments because most of the removal obligations are many years in the future and contracts and regulation often have vague descriptions of what constitutes removal. Pursuant to the accounting guidance relating to “ Assets Retirement Obligations Inherent to the present value calculation are numerous estimates, assumptions and judgments, including the ultimate settlement amounts, inflation factors, credit adjusted risk-free rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. To the extent future revisions to these assumptions impact the present value of the abandonment liability, the Company will make corresponding adjustments to both the asset retirement obligation and the related oil and natural gas property asset balance. Increases in the discounted abandonment liability resulting from the passage of time will be reflected as additional accretion expense in the consolidated statement of operations. The following summarizes the changes in the asset retirement obligation for the six months ended June 30, 2016: June 30, 2016 ($ Beginning of period $ 3,167 Liabilities incurred — Accretion 204 End of period $ 3,371 Capitalized Interest For exploration and development projects that have not commenced production, interest is capitalized as part of the historical cost of developing and constructing assets. Capitalized interest is determined by multiplying the Company’s weighted-average borrowing cost on debt by the average amount of qualifying costs incurred. Once an asset subject to interest capitalization is completed and placed in service, the associated capitalized interest is expensed through depreciation or impairment. See Note 7—Property, Plant, and Equipment and Note 9—Long-term Debt Earnings (Loss) Per Share Basic loss per share was calculated by dividing net income or loss applicable to common shares by the weighted average number of common shares outstanding during the periods presented. The weighted average number of shares used in the calculation for the three and six months ended June 30, 2016 were 409,920,869 and 409,590,679, respectively. The calculation of diluted loss per share includes the potential dilutive impact of non-vested restricted stock, non-vested restricted stock units, outstanding stock options, the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024 during the period, unless their effect is anti-dilutive. For the three and six months ended June 30, 2016, 8,808,708 shares of non-vested restricted stock, non-vested restricted stock units, outstanding stock options, the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024, were excluded from the diluted loss per share calculation because they were anti-dilutive. For the three and six months ended June 30, 2015, 9,967,516 shares of non-vested restricted stock, non-vested restricted stock units, outstanding stock options and the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024, were excluded from the diluted loss per share because they are anti-dilutive.

Cash and Cash Equivalents

Cash and Cash Equivalents	6 Months Ended
	Jun. 30, 2016
Cash And Cash Equivalents [Abstract]
Cash and Cash Equivalents	2. Cash and Cash Equivalents Cash and cash equivalents consisted of the following: June 30, 2016 December 31, 2015 ($ in thousands) Cash at banks $ 22,918 $ 33,173 Money market funds 23,064 — Held-to-maturity securities(1) 85,679 38,420 $ 131,661 $ 71,593 (1) These securities mature three months or less from the date of purchase.

Restricted Cash and Cash Equiva

Restricted Cash and Cash Equivalents and Investments	6 Months Ended
	Jun. 30, 2016
Restricted Cash And Investments [Abstract]
Restricted Cash and Cash Equivalents and Investments	3. Restricted Cash and Cash Equivalents and Investments Restricted cash and cash equivalents and investments consisted of the following: June 30, 2016 December 31, 2015 ($ in thousands) Angolan sale proceeds $ 250,000 $ 250,000 American Express Bank pledge agreement — 750 Citibank commercial card agreement 2,200 2,200 Total restricted funds(1) $ 252,200 $ 252,950 (1) Pursuant to the purchase and sale agreement governing the Angola Transaction, the Company received the First Payment of $250 million during the quarterly period ended September 30, 2015. See Note 10—Angola Transaction.

Joint Interest and Other Receiv

Joint Interest and Other Receivables	6 Months Ended
	Jun. 30, 2016
Receivables [Abstract]
Joint Interest and Other Receivables	4. Joint Interest and Other Receivables Joint interest and other receivables result primarily from billing shared costs under the respective operating agreements to the Company’s partners. These are usually settled within 30 days of the invoice date. As of June 30, 2016 and December 31, 2015, the balance in joint interest, revenue, and other receivables consisted of the following: June 30, 2016 December 31, 2015 ($ in thousands) Partners in the U.S. Gulf of Mexico $ 45,423 $ 50,766 Revenue receivable 1,909 — Accrued interest on investment securities 1,005 3,567 Other 595 376 $ 48,932 $ 54,709

Investments

Investments	6 Months Ended
	Jun. 30, 2016
Investments Debt And Equity Securities [Abstract]
Investments	5. Investments The Company’s investments in held-to-maturity securities, which are recorded at cost which approximates fair market value, were as follows as of June 30, 2016 and December 31, 2015: June 30, 2016 December 31, 2015 ($ in thousands) Corporate securities $ 120,501 $ 492,955 Commercial paper 526,383 604,986 U.S. Treasury securities 91,421 — Certificates of deposit — 20,750 Total $ 738,305 $ 1,118,691 The Company’s condensed consolidated balance sheet included the following held-to-maturity securities: June 30, 2016 December 31, 2015 ($ in thousands) Cash and cash equivalents $ 85,679 $ 38,420 Short-term investments 440,866 885,994 Restricted cash and cash equivalents and investments 202,716 194,277 Long-term restricted funds 9,044 — $ 738,305 $ 1,118,691 The contractual maturities of these held-to-maturity securities as of June 30, 2016 and December 31, 2015 were as follows: June 30, 2016 December 31, 2015 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value ($ in thousands) Within 1 year $ 738,305 $ 738,305 $ 1,118,691 $ 1,118,691 After 1 year — — — — $ 738,305 $ 738,305 $ 1,118,691 $ 1,118,691

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements The fair values of the Company’s cash and cash equivalents, joint interest and other receivables, short-term and long-term restricted funds and investments approximate their carrying amounts due to their short-term duration. The hierarchy below lists three levels of fair value based on the extent to which inputs used in measuring fair value are observable in the market. The Company categorizes each of its fair value measurements as applicable to one of these three levels based on the lowest level input that is significant to the fair value measurement in its entirety. The levels are: Level 1—Quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities. This category includes the Company’s cash and money market funds. Level 2—Quoted prices in non-active markets or in active markets for similar assets or liabilities, and inputs other than quoted prices that are observable, for the asset or liability, either directly or indirectly, for substantially the full contractual term of the asset or liability being measured. This category includes the Company’s U.S. Treasury bills, U.S. Treasury notes, commercial paper, U.S. agency securities, corporate bonds, and certificates of deposits. The Company secures valuations from its brokers to price U.S. Treasury bills, U.S. Treasury notes, commercial paper, U.S. agency securities, and corporate bonds. All of the Company’s brokers and custodians use Interactive Data Corporation as a third party pricing service to price corporate bonds, U.S. Treasury bills, U.S. Treasury notes, and U.S. agency securities, and S&P to price commercial paper. Level 3—Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. The Company does not currently have any financial instruments categorized as Level 3. The following tables summarize the Company’s significant financial instruments measured on a recurring basis as categorized by the fair value measurement hierarchy: Level 1 Level 2 Balance as of Carrying Value Fair Value(1) Carrying Value Fair Value(1) June 30, 2016 ($ in thousands) Cash and cash equivalents: Cash $ 22,918 $ 22,918 $ — $ — $ 22,918 Money market funds 23,064 23,064 — — 23,064 Commercial paper — — 85,679 85,679 85,679 Subtotal 45,982 45,982 85,679 85,679 131,661 Restricted cash and cash equivalents and investments: Money market funds 49,484 49,484 — — 49,484 Commercial paper — — 82,215 82,215 82,215 Corporate bonds — — 120,501 120,501 120,501 Certificates of deposit — — — — — Subtotal 49,484 49,484 202,716 202,716 252,200 Short-term investments: U.S. Treasury securities — — 82,377 82,377 82,377 Corporate bonds — — — — — Commercial paper — — 358,489 358,489 358,489 Certificates of deposit — — — — — Subtotal — — 440,866 440,866 440,866 Long-term restricted funds: U.S. Treasury securities — — 9,044 9,044 9,044 Subtotal — — 9,044 9,044 9,044 Total $ 95,466 $ 95,466 $ 738,305 $ 738,305 $ 833,771 Level 1 Level 2 Balance as of Carrying Value Fair Value(1) Carrying Value Fair Value(1) December 31, 2015 ($ in thousands) Cash and cash equivalents: Cash $ 33,173 $ 33,173 $ — $ — $ 33,173 Money market funds — — — — — Commercial paper — — 38,420 38,420 38,420 Subtotal 33,173 33,173 38,420 38,420 71,593 Restricted cash and cash equivalents: Money market funds 58,673 58,673 — — 58,673 Commercial paper — — 188,517 188,517 188,517 Corporate bonds — — 5,010 5,010 5,010 Certificates of deposit — — 750 750 750 Subtotal 58,673 58,673 194,277 194,277 252,950 Short-term investments: U.S. Agency securities — — — — — Corporate bonds — — 487,946 487,946 487,946 Commercial paper — — 378,048 378,048 378,048 Certificates of deposit — — 20,000 20,000 20,000 Subtotal — — 885,994 885,994 885,994 Long-term investments: Corporate bonds — — — — — Subtotal — — — — — Total $ 91,846 $ 91,846 $ 1,118,691 $ 1,118,691 $ 1,210,537 (1) As of June 30, 2016 and December 31, 2015, the Company did not record any OTTI on these assets.

Property, Plant, and Equipment

Property, Plant, and Equipment	6 Months Ended
	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Property, Plant, and Equipment	7. Property, Plant, and Equipment Property, plant, and equipment is stated at cost less accumulated depletion/depreciation/amortization and consisted of the following: Estimated Useful Life (Years) June 30, 2016 December 31, 2015 ($ in thousands) Oil and Gas Properties: Proved properties: Well and development costs $ 84,157 $ 71,463 Less: accumulated depletion (6,574 ) — Total proved properties 77,584 71,463 Unproved properties: Oil and gas leasehold 330,829 382,976 Less: accumulated valuation allowance (169,217 ) (175,963 ) 161,612 207,013 Exploration wells in process 762,329 615,258 Total unproved properties 923,941 822,271 Total oil and gas properties, net 1,001,526 893,734 Other Property and Equipment: Computer equipment and software 3 8,782 5,350 Office equipment and furniture 3 – 1,349 1,349 Leasehold improvements 3 – 2,150 2,150 12,281 8,849 Less: accumulated depreciation and amortization (7,533 ) (6,647 ) Total other property and equipment, net 4,748 2,202 Property, plant, and equipment, net $ 1,006,274 $ 895,936 The Company recorded $4.2 million and $0.4 million of depletion, depreciation and amortization expense for the three months ended June 30, 2016 and 2015, respectively, and $7.5 million and $0.8 million for the six months ended June 30, 2016 and 2015, respectively. Proved Oil and Gas Properties The Heidelberg project was formally sanctioned for development in mid-2013. As a result of the project sanction, the Company reclassified its Heidelberg exploration well costs to proved property well and development costs and these costs will be depleted as the related proved developed reserves are produced. During the quarter ended March 31, 2015, the Company assigned its 9.375% ownership interest in the Heidelberg prospect to its wholly owned subsidiary, Cobalt GOM #1 LLC (“GOM #1”). As a result, the carrying value of the costs capitalized for all the Heidelberg projects as of March 31, 2015 were transferred to GOM #1. As of June 30, 2016, prior to recognition of impairment charges, the well and development costs consisted of $102.4 million relating to exploration, appraisal and development well costs and $219.9 million for costs associated with field development. As of December 31, 2015, prior to recognition of impairment charges, the well and development costs consisted of $104.0 million relating to well costs for the Heidelberg #1 exploration well, Heidelberg #3 appraisal well, and the Heidelberg #4 and Heidelberg #6 development wells and $221.2 million for costs associated with field development. Unproved Oil and Gas Properties As of June 30, 2016 and December 31, 2015, the Company has the following unproved property acquisition costs, net of valuation allowance on the consolidated balance sheets: June 30, 2016 December 31, 2015 ($ in thousands) Individual oil and gas leaseholds with carrying value greater than $1 million $ 255,203 $ 305,270 Individual oil and gas leaseholds with carrying value less than $1 million 75,626 77,706 330,829 382,976 Accumulated valuation allowance (169,217 ) (175,963 ) Total oil and gas leasehold $ 161,612 $ 207,013 Capitalized Exploration Well Costs If an exploration well provides evidence as to the existence of sufficient quantities of hydrocarbons to justify evaluation for potential development, drilling costs associated with the well are initially capitalized, or suspended, pending a determination as to whether a commercially sufficient quantity of proved reserves can be attributed to the area as a result of drilling. This determination may take longer than one year in certain areas (generally, deepwater and international locations) depending upon, among other things, (i) the amount of hydrocarbons discovered, (ii) the outcome of planned geological and engineering studies, (iii) the need for additional appraisal drilling activities to determine whether the discovery is sufficient to support an economic development plan and (iv) the requirement for government sanctioning in international locations before proceeding with development activities. The following tables reflect the Company’s net changes in and the cumulative costs of capitalized exploration well costs (excluding any related leasehold costs): June 30, 2016 December 31, 2015 ($ in thousands) Beginning of period $ 615,258 $ 330,099 Additions to capitalized exploration Exploration well costs 236,069 285,118 Capitalized interest 22,621 24,161 Reclassifications to wells, facilities, and equipment based on determination of proved reserves — — Amounts charged to expense(1) (111,619 ) (24,120 ) End of period $ 762,329 $ 615,258 (1) The amounts of $111.6 million for the six months ended June 30, 2016 and $24.1 million for the year ended December 31, 2015, represents impairment charges on exploration wells drilled in the U.S. Gulf of Mexico which did not encounter commercial hydrocarbons. June 30, 2016 December 31, 2015 ($ in thousands) Cumulative costs: Exploration well costs $ 701,144 $ 576,694 Capitalized interest 61,185 38,564 $ 762,329 $ 615,258 Well costs capitalized for a period greater than one year after completion of drilling (included in table above) $ 362,187 $ 351,753 As of June 30, 2016, capitalized exploration well costs that have been suspended longer than one year are associated with the Company’s Shenandoah, North Platte, Anchor, and Diaman discoveries. These well costs are suspended pending ongoing evaluation including, but not limited to, results of additional appraisal drilling, well-test analysis, additional geological and geophysical data and approval of a development plan. Management believes these discoveries exhibit sufficient indications of hydrocarbons to justify potential development and is actively pursuing efforts to fully assess them. If additional information becomes available that raises substantial doubt as to the economic or operational viability of these discoveries, the associated costs will be expensed at that time. The Heidelberg discovery has been sanctioned for development and the Heidelberg capitalized exploration and appraisal well costs were reclassified to development costs in 2013. In January 2016, the Company achieved initial production of oil and gas from the Heidelberg field.

Other Assets

Other Assets	6 Months Ended
	Jun. 30, 2016
Other Assets [Abstract]
Other Assets	8. Other Assets As of June 30, 2016 and December 31, 2015, the balance in other assets consisted of the following: June 30, 2016 December 31, 2015 (in thousands) Debt issue costs(1) $ — $ 3,595 Rig costs(2) 8,331 15,397 Other deposits 500 — $ 8,831 $ 18,992 (1) As of June 30, 2016 and December 31, 2015, the $0 million and $3.6 million, respectively, in debt issue costs was related to the issuance of the Borrowing Base Facility Agreement, as described in Note 9. On June 17, 2016, the Company terminated the Borrowing Base Facility Agreement and all associated costs were written off. (2) As of June 30, 2016 and December 31, 2015, the $8.3 million and $15.4 million, respectively, relate to costs associated with the Rowan Reliance drilling rig which is currently drilling in U.S. Gulf of Mexico. These costs are capitalized to the wells over the term of the respective drilling rig contracts.

Long-term Debt

Long-term Debt	6 Months Ended
	Jun. 30, 2016
Long Term Debt [Abstract]
Long-term Debt	9. Long-term Debt As of June 30, 2016, the Company’s long-term debt consists of the 2.625% convertible senior notes due 2019 issued on December 17, 2012 (the “2.625% Notes”), and the 3.125% convertible senior notes due 2024 issued on May 13, 2014 (the “3.125% Notes”, and, collectively with the 2.625% Notes, the “Notes”), as follows: Borrowing Base Facility Agreement On June 17, 2016, Cobalt GOM #1 LLC (“GOM #1”), an indirect wholly-owned subsidiary of the Company, terminated the Borrowing Base Facility Agreement among GOM #1, the Company, Société Générale, as administrative agent, and certain other lenders named therein (the “Facility Agreement”). The Facility Agreement provided for a limited recourse $150 million senior secured reserve-based term loan facility, with an amount available for borrowing at any one time limited to a periodically adjusted borrowing base amount. Based on discussions between the Company and the lenders under the Facility Agreement, the borrowing base amount under the Facility Agreement was expected to be materially reduced to a level that would not justify the ongoing expense of maintaining the facility. No borrowings were outstanding under the Facility Agreement at the time of termination, and no prepayment fees were payable by the Company or GOM #1 upon termination. Following termination of the Facility Agreement, all liens, mortgages, pledges and other security provided in favor of the lenders in connection with the Facility Agreement were terminated and released. In June 2016, the Company 2.625% Convertible Senior Notes due 2019 On December 17, 2012, the Company issued $1.38 billion aggregate principal amount of the 2.625% Notes. The 2.625% Notes are the Company’s senior unsecured obligations and interest is payable semi-annually in arrears on June 1 and December 1 of each year. The 2.625% Notes will mature on December 1, 2019, unless earlier repurchased or converted in accordance with the terms of the 2.625% Notes. The 2.625% Notes may be converted at the option of the holder at any time prior to 5:00 p.m., New York City time, on the second scheduled trading day immediately preceding the maturity date, in multiples of $1,000 principal amount. The 2.625% Notes are convertible at an initial conversion rate of 28.023 shares of common stock per $1,000 principal amount, representing an initial conversion price of approximately $35.68 per share for a total of approximately 38.7 million underlying shares. The conversion rate is subject to adjustment upon the occurrence of certain events, as defined in the indenture governing the 2.625% Notes, but will not be adjusted for any accrued and unpaid interest except in limited circumstances. Upon conversion, the Company’s conversion obligation may be satisfied, at the Company’s option, in cash, shares of common stock or a combination of cash and shares of common stock. 3.125% Convertible Senior Notes due 2024 On May 13, 2014, the Company issued $1.3 billion aggregate principal amount of the 3.125% Notes. The 3.125% Notes are the Company’s senior unsecured obligations and rank equal in right of payment to the 2.625% Notes. Interest on the 3.125% Notes is payable semi-annually in arrears on May 15 and November 15 of each year. The 3.125% Notes will mature on May 15, 2024, unless earlier repurchased, converted or redeemed in accordance with the terms of the Notes. Prior to November 15, 2023, the 3.125% Notes are convertible only under the following circumstances: (1) during any fiscal quarter commencing after March 31, 2015 (and only during such fiscal quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a 30 consecutive trading-day period ending on, and including, the last trading day of the immediately preceding fiscal quarter exceeds $30.00 on each applicable trading day; (2) during the five business-day period after any five consecutive trading-day period (the “3.125% Notes Measurement Period”) in which the trading price per $1,000 principal amount of notes for each trading day of the 3.125% Notes Measurement Period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (3) if the Company calls all or any portion of the 3.125% Notes for redemption, at any time prior to 5:00 p.m., New York City time, on the second scheduled trading day immediately preceding the related redemption date; or (4) upon the occurrence of specified distributions or the occurrence of specified corporate events. On or after November 15, 2023, the 3.125% Notes may be converted at the option of the holder at any time prior to 5:00 p.m., New York City time, on the second scheduled trading day immediately preceding the stated maturity date, in multiples of $1,000 principal amount. As of June 30, 2016, none of the conditions allowing holders of the 3.125% Notes to convert had been met. The 3.125% Notes are convertible at an initial conversion rate of 43.3604 shares of common stock per $1,000 principal amount, representing an initial conversion price of approximately $23.06 per share for a total of approximately 56.4 million underlying shares. The conversion rate is subject to adjustment upon the occurrence of certain events, as defined in the indenture governing the 3.125% Notes, but will not be adjusted for any accrued and unpaid interest except in limited circumstances. Upon conversion, the Company’s conversion obligation may be satisfied, at the Company’s option, in cash, shares of common stock or a combination of cash and shares of common stock. Holders of the Notes who convert their Notes in connection with a “make-whole fundamental change”, as defined in the indenture governing these Notes, may be entitled to a make-whole premium in the form of an increase in the conversion rate. Additionally, in the event of a fundamental change, as defined in the indenture governing the Notes, holders of the Notes may require the Company to repurchase for cash all or a portion of their Notes equal to $1,000 or a multiple of $1,000 at a fundamental change repurchase price equal to 100% of the principal amount of Notes, plus accrued and unpaid interest, if any, to, but not including, the fundamental change repurchase date. Upon the occurrence of an Event of Default, as defined within the indenture governing the Notes, the trustee or the holders of at least 25% in aggregate principal amount of the Notes then outstanding may declare 100% of the principal of, and accrued and unpaid interest on, all the Notes to be due and payable immediately. In accordance with accounting guidance relating to, “ Debt with Conversion and Other Options The carrying amounts of the liability components of the Notes were as follows: June 30, 2016 December 31, 2015 Principal Amount Unamortized discount and debt issuance costs (1) Carrying Amount Principal Amount Unamortized discount and debt issuance costs Carrying Amount ($ in thousands) Carrying amount of liability component 2.625% Notes $ 1,380,000 $ (229,048 ) $ 1,150,952 $ 1,380,000 $ (258,565 ) $ 1,121,435 3.125% Notes 1,300,000 (420,231 ) 879,769 1,300,000 (439,540 ) 860,460 Total $ 2,680,000 $ (649,279 ) $ 2,030,721 $ 2,680,000 $ (698,105 ) $ 1,981,895 (1) Unamortized discount and debt issuance costs will be amortized over the remaining life of the Notes which is 3.5 years for the 2.625% Notes and 8.0 years for the 3.125% Notes. See Note 1 related to a change in the classification of unamortized debt issuance costs on the Condensed Consolidated Balance Sheets. The carrying amounts of the equity components of the Notes were as follows: June 30, 2016 December 31, 2015 ($ in thousands) Debt discount relating to value of conversion option $ 866,340 $ 866,340 Debt issue costs (20,185 ) (20,185 ) Total $ 846,155 $ 846,155 Fair Value The fair value of the Notes was calculated based on the fair value of similar debt instruments since an observable quoted price of the Notes or a similar asset or liability is not readily available (Level 2 inputs). As of June 30, 2016 and December 31, 2015, the fair values of the Notes were as follows: June 30, 2016 December 31, 2015 ($ in thousands) 2.625% Notes $ 503,700 $ 793,500 3.125% Notes 432,276 640,250 Total $ 935,976 $ 1,433,750 As of June 30, 2016, the Company had $7.8 million accrued for interest on the Notes. For the three months ended June 30, 2016 and 2015, the interest expense, net of capitalized amount, relating to the Notes and certain costs and commitment fees associated with the Facility Agreement was $16.0 million and $17.8 million, respectively. For the six months ended June 30, 2016 and 2015, the interest expense, net of capitalized amount, relating to the Notes and certain costs and commitment fees associated with the Facility Agreement was $31.6 million and $37.9 million, respectively. As of June 30, 2016 and December 31, 2015, the debt discounts associated with the 2.625% Notes and the 3.125% Notes resulted in the recognition of $217.5 million and $233.6 million of deferred tax liability, respectively.

Angola Transaction

Angola Transaction	6 Months Ended
	Jun. 30, 2016
Discontinued Operations And Disposal Groups [Abstract]
Angola Transaction	10. Angola Transaction On August 22, 2015, Cobalt International Energy Angola Ltd. (“Cobalt Angola”), a wholly-owned subsidiary of the Company, executed a purchase and sale agreement (the “Purchase and Sale Agreement”) with Sonangol for the sale by Cobalt Angola to Sonangol of the entire issued and outstanding share capital of CIE Angola Block 20 Ltd. and CIE Angola Block 21 Ltd., which respectively hold the Company’s 40% working interest in each of Block 20 and Block 21 offshore Angola for aggregate gross consideration of $1.75 billion before Angolan withholding taxes of approximately $19.7 million (to be netted out of the gross consideration to be paid to Cobalt Angola) and certain other U.S. and Angolan taxes, expenses, and contingent liabilities (the “Angola Transaction”). In accordance with the Purchase and Sale Agreement, Sonangol paid the Company $250 million (the “First Payment”). The First Payment has been reported as restricted cash and a liability on the balance sheet. Sonangol Pesquisa e Produção, S.A., an affiliate of Sonangol, currently holds a 30% working interest in Block 20 and a 60% working interest in Block 21. The Angola Transaction is subject to Angolan government approvals. On July 26, 2016, the Company’s Chief Executive Officer met with Sonangol’s Chairwoman of the Board of Directors Isabel dos Santos and members of her executive team in Luanda, Angola to discuss the status of the Angolan Transaction. At this meeting, it was jointly agreed with Sonangol that the Company would market its working interests in Blocks 20 and 21 for sale by the Company to a third party other than Sonangol. On August 1, 2016, the Company received a letter from Chairwoman Isabel dos Santos confirming Sonangol’s support of such marketing and sale process. The Company therefore believes that it is unlikely that the Angola Transaction will close pursuant to the terms of the Purchase and Sale Agreement and believe that it is likely that the Purchase and Sale Agreement will automatically terminate on August 22, 2016. In such a case, the Purchase and Sale Agreement provides that the parties are to be restituted in order to put them in their original positions as if no agreement had been executed. The Company plans to work with Sonangol to understand and agree on the financial and operational implications of this provision including with respect to the return of the First Payment and the payment of the $158.6 million of receivables owed to the Company by Sonangol. With respect to the marketing of its Angolan assets, the Company intends to immediately commence the marketing and sale process. Assets and Liabilities Held for Sale The following table summarizes the assets and liabilities associated with Blocks 9, 20, and 21 offshore Angola. Although the Company relinquished its working interest in Block 9 on February 29, 2016, the Company continues to have assets and liabilities associated with the entity. The Company continues to assess the balances for possible impairment as the assets and liabilities held for sale are required to be presented at fair value. There has been no impairment identified to date. June 30, 2016 December 31, 2015 ($ in thousands) Cash and cash equivalents $ 43,527 $ 8,578 Joint interest and other receivables 159,542 156,599 Prepaid expenses and other current assets 5,025 8,216 Inventory 43,147 56,224 Short term restricted funds — 22,538 Oil and gas properties 1,611,828 1,465,299 Other property and equipment, net 10,107 10,107 Long term restricted funds — 82,568 Other assets 338 922 Total assets of the discontinued operation 1,873,514 1,811,051 Trade and other accounts payable (20,528 ) (6,089 ) Accrued liabilities (81,415 ) (128,259 ) Short term contractual obligations (92,076 ) (115,110 ) Long term contractual obligations (2,688 ) (1,381 ) Other long term liabilities — — Total liabilities of the discontinued operation $ (196,707 ) $ (250,839 ) Results for Blocks 9, 20, and 21 offshore Angola classified within discontinued operations consisted of the following: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Seismic and exploration $ 3,093 $ 5,646 $ 10,410 $ 9,348 Dry hole expense and impairment (1,677 ) 611 1,874 611 General and administrative 3,688 6,258 13,009 12,778 Depreciation and amortization — 926 — 1,856 Gain on the release of letters of credit (1) — — (4,375 ) — Net loss from discontinued operations $ 5,104 $ 13,441 $ 20,918 $ 24,593 (1) Amount represents the gain recognized on the release of the Block 9 letter of credit that was previously written off.

Seismic and Exploration Expense

Seismic and Exploration Expenses	6 Months Ended
	Jun. 30, 2016
Oil And Gas Exploration And Production Industries Disclosures [Abstract]
Seismic and Exploration Expenses	11. Seismic and Exploration Expenses Seismic and exploration expenses consisted of the following: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Seismic costs $ 3,024 $ 7,970 $ 570 $ 19,801 Leasehold delay rentals 3,297 2,936 4,561 4,327 Other exploration expense 14 361 (50 ) 1,206 $ 6,335 $ 11,267 $ 5,081 $ 25,334

Equity Based Compensation

Equity Based Compensation	6 Months Ended
	Jun. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Based Compensation	12. Equity Based Compensation The Company accounts for stock-based compensation at fair value. The Company grants various types of stock-based awards including stock options, stock appreciation rights, restricted stock, restricted stock units and performance-based awards. The fair value of stock option awards is determined using the Black-Scholes-Merton option-pricing model. For restricted stock awards with market conditions, the fair value of the awards is measured using the Monte Carlo pricing model. Restricted stock awards without market conditions are valued using the market price of the Company’s common stock on the grant date. The Company records compensation cost, net of estimated forfeitures, for stock-based compensation awards over the requisite service period except for performance-based awards, which are amortized on a straight-line basis over a weighted average period. During the six months ended June 30, 2016, the Company granted a total of 571,428 shares of restricted stock, 3,491,352 restricted stock units and 1,129,944 stock options to employees which include 571,428 shares of restricted stock and 1,129,944 stock options with both service and market conditions granted to two senior officers under the terms of their employment agreements. During the six months ended June 30, 2016, the Company granted 82,898 shares of common stock as retainer awards and 362,934 restricted stock units to its non-employee directors. On February 18, 2016, the Company granted 3,491,352 restricted stock units (“RSUs”) under the Company’s 2015 Long Term Incentive Plan (the “2015 Plan”) to the Company’s employees based on the common stock market price at the time of issuance of $2.44 per share. The RSU’s will vest in equal installments on each of March 1, 2017, March 1, 2018, and March 1, 2019 by issuance of the Company’s shares of common stock or by cash or by a combination thereof, at the discretion of the Company. The fair value of the RSU’s on the date of grant was $10.4 million. The Company accounts for the RSUs as compensation cost and records a corresponding liability based on the fair value of the RSUs at the end of each reporting period. For the three months ended June 30, 2016 and 2015, the Company recognized $1.3 million and $0.0 million, respectively, in compensation expense relating to the RSU awards. For the six months ended June 30, 2016 and 2015, the Company recognized $1.3 million and $0.0 million, respectively, in compensation expense relating to the RSU awards. The Company recorded equity based compensation expense, net of forfeitures, of ($4.9) million and $7.1 million for the three months ended June 30, 2016 and 2015, respectively. The Company recorded equity based compensation expense, net of forfeitures, of $2.8 million and $13.0 million for the six months ended June 30, 2016 and 2015, respectively. On February 20, 2015, the Company issued a total of 1,526,835 share appreciation rights (“SARs”) under the Company’s Long Term Incentive Plan to the Company’s officers, based on the common stock market price at the time of issuance of $8.87 per share. The SARs will vest with respect to one-third (1/3) of the underlying shares on each anniversary of the grant date over the next three years and may be settled, at the Company’s discretion, by issuance of the Company’s shares or by cash or by a combination of the Company’s shares and cash based on the fair market value of the shares on date of exercise. The fair value of a SAR is determined using the Black-Scholes-Merton option-pricing model which at the date of grant was $4.53 per SAR share. The Company accounts for the SAR awards as compensation cost and records a corresponding liability based on the fair value of the SARs at the end of each reporting period. As of June 30, 2016, the fair value of each SAR decreased to $2.74, resulting in a reduction of the fair value of $1.3 million. For the three months ended June 30, 2016 and 2015, the Company recognized $0.1 million and $0.4 million, respectively, in compensation expense relating to the SAR awards. For the six months ended June 30, 2016 and 2015, the Company recognized $0.6 million and $0.9 million, respectively, in compensation expense relating to the SAR. On April 30, 2015, the Company’s stockholders approved the 2015 Plan. The total number of shares of the Company’s common stock available for issuance under the 2015 Plan is 12,000,000. The 2015 Plan provides for grants of stock options, stock appreciation rights, restricted stock, restricted stock units, performance awards and other stock-based awards. As of June 30, 2016, the Company has awarded 1,851,372 shares under the 2015 Plan, not including the 3,491,352 RSU’s which may be settled in cash at the Company’s election.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income taxes	13. Income taxes We recorded no income tax expense or benefit for the three and six months ended June 30, 2016. We increased our valuation allowance and reduced our net deferred tax assets to zero during 2009 after considering all available positive and negative evidence related to the realization of our deferred tax assets. Our assessment of the realization of our deferred tax assets has not changed, and as a result we continue to maintain a full valuation allowance for our net deferred assets as of June 30, 2016. As of June 30, 2016, we have no unrecognized tax benefits. There were no significant changes to the calculation since December 31, 2015.

Contingencies

Contingencies	6 Months Ended
	Jun. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Contingencies	14. Contingencies The Company is currently, and from time to time may be, subject to various lawsuits, claims and proceedings that arise in the normal course of business, including employment, commercial, environmental, safety and health matters. It is not presently possible to determine whether any such matters will have a material adverse effect on the Company’s consolidated financial position, results of operations, or liquidity.

Other Matters

Other Matters	6 Months Ended
	Jun. 30, 2016
Legal Proceedings Disclosure [Abstract]
Other Matters	15. Other Matters As previously disclosed, in November 2011 a formal order of investigation was issued by the SEC related to the Company’s operations in Angola. In August 2014, the Company received a Wells Notice from the SEC related to this investigation. In January 2015, the Company received a termination letter from the SEC advising that the SEC’s FCPA investigation has concluded and the Staff does not intend to recommend any enforcement action by the SEC. This letter formally concluded the SEC’s investigation. The Company continues to cooperate with the Department of Justice (“DOJ”) with regard to its ongoing parallel investigation. The Company is unable to predict the outcome of the DOJ’s ongoing investigation or any action that the DOJ may decide to pursue. On February 19, 2016, the Company initiated a workforce reduction program in response to the Angola Transaction and prolonged commodity price weakness, which has resulted in a reduction of the Company’s capital programs and other operations. The Company expects to recognize the majority of these restructuring costs in the first and second quarters of 2016 and will recognize the remaining costs throughout 2016 until the remaining employee terminations have occurred. Included in the three and six months ended June 30, 2016 was $3.0 million and $6.1 million, respectively, of severance costs associated with the Company’s workforce reduction plan.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the financial statements of Cobalt International Energy, Inc. and all of its wholly-owned subsidiaries. All significant intercompany transactions and amounts have been eliminated for all periods presented. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) for interim financial information and the appropriate rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, the condensed consolidated financial statements do not include all of the information and footnote disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for interim periods are not necessarily indicative of the results that may be presented for the entire year. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015.
Correction of Immaterial Errors	Correction of Immaterial Errors The accompanying unaudited condensed financial statements for the six months ended June 30, 2016 include a reduction of impairment charges related to the Heidelberg field totaling approximately $8.5 million related to the prior year. The amounts were not deemed material with respect to such prior year or the anticipated results and the trend of earnings for fiscal year 2016.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (“ASU 2016-02”), Leases (Subtopic 842). Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, unlike current GAAP, which requires only capital leases to be recognized on the balance sheet, ASU 2016-02 will require both types of leases to be recognized on the balance sheet. ASU 2016-02 also will require disclosures to help investors and other financial statement users to better understand the amount, timing and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. ASU 2016-02 does not apply for leases for oil and gas properties, but does apply to equipment used to explore and develop oil and gas resources. The Company currently does not have any leases classified as financing leases. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018 and is to be applied using the modified retrospective approach. The Company has not yet fully determined or quantified the effect ASU 2016-02 will have on the Company’s financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09 (“ASU 2016-09”), Compensation – Stock Compensation (Subtopic 718). The objective of ASU 2016-09 is for simplification involving several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016 and early adoption is permitted. The Company has not yet fully determined or quantified the effect ASU 2016-09 will have on the Company’s financial statements. In May 2016, the FASB issued Accounting Standards Update No. 2016-11 (“ASU 2016-11”), Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting. The guidance requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. The Company is required to adopt the new standards in the first quarter of 2018 using one of two retrospective application methods. The Company is continuing to evaluate the provisions of these ASUs, and has not determined the impact these standards may have on its consolidated financial statements and related disclosures or decided upon the method of adoption. In April 2015, Financial Accounting Standards Board (FASB) amended Accounting Standard Codification Subtopic No. 835-30, Interest—Imputation of Interest (the “ASC Subtopic 835-30”). The amendments require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments. The amendments under ASC Subtopic 835-30 are effective for financial statements issued for fiscal years beginning after December 15, 2015 and interim periods within those fiscal years. The adoption of ASU 2015-03 resulted in $32.9 million of unamortized debt issuance costs reclassified from long-term assets to a reduction in long-term liabilities as of December 31, 2015. In July 2015, the FASB issued Accounting Standards Update (ASU) 2015-11, "Accounting for Inventory" (ASU 2015-11), which requires entities to measure most inventory at lower of cost or net realizable value. ASU 2015-11 defines net realizable value as "the estimated selling prices in the ordinary course of business, less reasonably predictable cost of completion, disposal and transportation." ASU 2015-11 is effective prospectively for interim and annual periods beginning after December 15, 2016. The Company adopted the amendments to ASC 2015-11 on January 1, 2016. The adoption of ASC 2015-11 did not have material impact on the Company’s financial statements. In August 2014, the FASB issued a new standard related to the disclosure of uncertainties about an entity's ability to continue as a going concern (ASU 2014-15). The new standard will explicitly require management to assess an entity's ability to continue as a going concern every reporting period and to provide related footnote disclosures in certain circumstances. The new standard will be effective for all entities in the first annual period ending after December 15, 2016, with early adoption permitted. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09 (“ASU 2014-09”), Summary and Amendments That Create Revenue from Contracts and Customers (Subtopic 606). ASU 2014-09 amends and replaces current revenue recognition requirements, including most industry-specific guidance. The revised guidance establishes a five step approach to be utilized in determining when, and if, revenue should be recognized. ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2017. Upon application, an entity may elect one of two methods, either restatement of prior periods presented or recording a cumulative adjustment in the initial period of application. The Company has not determined the effect ASU 2014-09 will have on the recognition of its revenue, if any, nor has the Company determined the method the Company will utilize upon adoption, which would be in the first quarter of 2018.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates made by the Company include (i) accruals related to expenses, (ii) assumptions used in estimating fair value of equity based awards and the fair value of the liability component of the convertible senior notes and (iii) assumptions used in impairment testing. Although the Company believes these estimates are reasonable, actual results could differ from these estimates.
Investments	Investments The Company’s policy on accounting for its investments, which consist entirely of debt securities, is based on the accounting guidance relating to “ Accounting for Certain Investments in Debt and Equity Securities See Note 5—Investments Investments are considered to be impaired when a decline in fair value is determined to be other-than-temporary. The Company conducts a regular assessment of its debt securities with unrealized losses to determine whether securities have other-than-temporary impairment (“OTTI”). This assessment considers, among other factors, the nature of the securities, credit rating or financial condition of the issuer, the extent and duration of the unrealized loss, market conditions and whether the Company intends to sell or whether it is more likely than not that the Company will be required to sell the debt securities. As of June 30, 2016 and December 31, 2015, the Company has no OTTI in its debt securities.
Property, Plant, and Equipment	Property, Plant, and Equipment The Company uses the “successful efforts” method of accounting for its oil and gas properties. Acquisition costs for unproved leasehold properties and costs of drilling exploration wells are capitalized pending determination of whether proved reserves can be attributed to the areas as a result of drilling those wells. Under the successful efforts method of accounting, proved leasehold costs are capitalized and amortized over the proved developed and undeveloped reserves on a units-of-production basis. Successful drilling costs, costs of development and developmental dry holes are capitalized and amortized over the proved developed reserves on a units-of-production basis. When circumstances indicate that proved oil and gas properties may be impaired, the Company compares expected undiscounted future cash flows at a depreciation, depletion and amortization group level to the unamortized capitalized cost of the asset. If the expected undiscounted future cash flows, based on the Company's estimate of future crude oil and natural gas prices, operating costs, anticipated production from proved reserves and other relevant data, are lower than the unamortized capitalized cost, the capitalized cost is reduced to fair value. Fair value is generally calculated using the Income Approach described in the Fair Value Measurement Topic of the ASC. Significant unproved leasehold costs are capitalized and are not amortized, pending an evaluation of their exploration potential. Unproved leasehold costs are assessed periodically to determine if an impairment of the cost of individual properties has occurred. Factors taken into account for impairment analysis include results of the technical studies conducted, lease terms and management’s future exploration plans. The cost of impairment is charged to expense in the period in which it occurs. Costs incurred for exploration dry holes, geological and geophysical work (including the cost of seismic data), and delay rentals are charged to expense as incurred. Costs of other property and equipment are depreciated on a straight-line basis based on their respective useful lives.
Asset Retirement Obligation	Asset Retirement Obligation The Company expects to have significant obligations under its lease agreements and federal regulation to remove its equipment and restore land or seabed at the end of oil and natural gas production operations. These asset retirement obligations (“ARO”) are primarily associated with plugging and abandoning wells and removing and disposing of offshore oil and natural gas platforms. Estimating the future restoration and removal cost is difficult and requires the Company to make estimates and judgments because most of the removal obligations are many years in the future and contracts and regulation often have vague descriptions of what constitutes removal. Pursuant to the accounting guidance relating to “ Assets Retirement Obligations Inherent to the present value calculation are numerous estimates, assumptions and judgments, including the ultimate settlement amounts, inflation factors, credit adjusted risk-free rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. To the extent future revisions to these assumptions impact the present value of the abandonment liability, the Company will make corresponding adjustments to both the asset retirement obligation and the related oil and natural gas property asset balance. Increases in the discounted abandonment liability resulting from the passage of time will be reflected as additional accretion expense in the consolidated statement of operations. The following summarizes the changes in the asset retirement obligation for the six months ended June 30, 2016: June 30, 2016 ($ Beginning of period $ 3,167 Liabilities incurred — Accretion 204 End of period $ 3,371
Capitalized Interest	Capitalized Interest For exploration and development projects that have not commenced production, interest is capitalized as part of the historical cost of developing and constructing assets. Capitalized interest is determined by multiplying the Company’s weighted-average borrowing cost on debt by the average amount of qualifying costs incurred. Once an asset subject to interest capitalization is completed and placed in service, the associated capitalized interest is expensed through depreciation or impairment. See Note 7—Property, Plant, and Equipment and Note 9—Long-term Debt
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic loss per share was calculated by dividing net income or loss applicable to common shares by the weighted average number of common shares outstanding during the periods presented. The weighted average number of shares used in the calculation for the three and six months ended June 30, 2016 were 409,920,869 and 409,590,679, respectively. The calculation of diluted loss per share includes the potential dilutive impact of non-vested restricted stock, non-vested restricted stock units, outstanding stock options, the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024 during the period, unless their effect is anti-dilutive. For the three and six months ended June 30, 2016, 8,808,708 shares of non-vested restricted stock, non-vested restricted stock units, outstanding stock options, the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024, were excluded from the diluted loss per share calculation because they were anti-dilutive. For the three and six months ended June 30, 2015, 9,967,516 shares of non-vested restricted stock, non-vested restricted stock units, outstanding stock options and the 2.625% convertible senior notes due 2019 and the 3.125% convertible senior notes due 2024, were excluded from the diluted loss per share because they are anti-dilutive.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Schedule of changes in asset retirement obligation	The following summarizes the changes in the asset retirement obligation for the six months ended June 30, 2016: June 30, 2016 ($ Beginning of period $ 3,167 Liabilities incurred — Accretion 204 End of period $ 3,371

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	6 Months Ended
	Jun. 30, 2016
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	Cash and cash equivalents consisted of the following: June 30, 2016 December 31, 2015 ($ in thousands) Cash at banks $ 22,918 $ 33,173 Money market funds 23,064 — Held-to-maturity securities(1) 85,679 38,420 $ 131,661 $ 71,593 (1) These securities mature three months or less from the date of purchase.

Restricted Cash and Cash Equi25

Restricted Cash and Cash Equivalents Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Restricted Cash And Investments [Abstract]
Schedule of Restricted Cash and Cash Equivalents and Investments	Restricted cash and cash equivalents and investments consisted of the following: June 30, 2016 December 31, 2015 ($ in thousands) Angolan sale proceeds $ 250,000 $ 250,000 American Express Bank pledge agreement — 750 Citibank commercial card agreement 2,200 2,200 Total restricted funds(1) $ 252,200 $ 252,950 (1) Pursuant to the purchase and sale agreement governing the Angola Transaction, the Company received the First Payment of $250 million during the quarterly period ended September 30, 2015. See Note 10—Angola Transaction.

Joint Interest and Other Rece26

Joint Interest and Other Receivables (Tables)	6 Months Ended
	Jun. 30, 2016
Receivables [Abstract]
Schedule of joint interest, revenue and other receivables	June 30, 2016 December 31, 2015 ($ in thousands) Partners in the U.S. Gulf of Mexico $ 45,423 $ 50,766 Revenue receivable 1,909 — Accrued interest on investment securities 1,005 3,567 Other 595 376 $ 48,932 $ 54,709

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments Debt And Equity Securities [Abstract]
Schedule of Fair Value of Held-to-maturity Securities Recorded at Amortized Cost	The Company’s investments in held-to-maturity securities, which are recorded at cost which approximates fair market value, were as follows as of June 30, 2016 and December 31, 2015: June 30, 2016 December 31, 2015 ($ in thousands) Corporate securities $ 120,501 $ 492,955 Commercial paper 526,383 604,986 U.S. Treasury securities 91,421 — Certificates of deposit — 20,750 Total $ 738,305 $ 1,118,691
Schedule of Held-to-maturity Securities Included in the Company's Condensed Consolidated Balance Sheet	The Company’s condensed consolidated balance sheet included the following held-to-maturity securities: June 30, 2016 December 31, 2015 ($ in thousands) Cash and cash equivalents $ 85,679 $ 38,420 Short-term investments 440,866 885,994 Restricted cash and cash equivalents and investments 202,716 194,277 Long-term restricted funds 9,044 — $ 738,305 $ 1,118,691
Schedule of Contractual Maturities of Held-to-maturity Securities	The contractual maturities of these held-to-maturity securities as of June 30, 2016 and December 31, 2015 were as follows: June 30, 2016 December 31, 2015 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value ($ in thousands) Within 1 year $ 738,305 $ 738,305 $ 1,118,691 $ 1,118,691 After 1 year — — — — $ 738,305 $ 738,305 $ 1,118,691 $ 1,118,691

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Significant Financial Instruments Measured on a Recurring Basis as Categorized by the Fair Value Measurement Hierarchy	The following tables summarize the Company’s significant financial instruments measured on a recurring basis as categorized by the fair value measurement hierarchy: Level 1 Level 2 Balance as of Carrying Value Fair Value(1) Carrying Value Fair Value(1) June 30, 2016 ($ in thousands) Cash and cash equivalents: Cash $ 22,918 $ 22,918 $ — $ — $ 22,918 Money market funds 23,064 23,064 — — 23,064 Commercial paper — — 85,679 85,679 85,679 Subtotal 45,982 45,982 85,679 85,679 131,661 Restricted cash and cash equivalents and investments: Money market funds 49,484 49,484 — — 49,484 Commercial paper — — 82,215 82,215 82,215 Corporate bonds — — 120,501 120,501 120,501 Certificates of deposit — — — — — Subtotal 49,484 49,484 202,716 202,716 252,200 Short-term investments: U.S. Treasury securities — — 82,377 82,377 82,377 Corporate bonds — — — — — Commercial paper — — 358,489 358,489 358,489 Certificates of deposit — — — — — Subtotal — — 440,866 440,866 440,866 Long-term restricted funds: U.S. Treasury securities — — 9,044 9,044 9,044 Subtotal — — 9,044 9,044 9,044 Total $ 95,466 $ 95,466 $ 738,305 $ 738,305 $ 833,771 Level 1 Level 2 Balance as of Carrying Value Fair Value(1) Carrying Value Fair Value(1) December 31, 2015 ($ in thousands) Cash and cash equivalents: Cash $ 33,173 $ 33,173 $ — $ — $ 33,173 Money market funds — — — — — Commercial paper — — 38,420 38,420 38,420 Subtotal 33,173 33,173 38,420 38,420 71,593 Restricted cash and cash equivalents: Money market funds 58,673 58,673 — — 58,673 Commercial paper — — 188,517 188,517 188,517 Corporate bonds — — 5,010 5,010 5,010 Certificates of deposit — — 750 750 750 Subtotal 58,673 58,673 194,277 194,277 252,950 Short-term investments: U.S. Agency securities — — — — — Corporate bonds — — 487,946 487,946 487,946 Commercial paper — — 378,048 378,048 378,048 Certificates of deposit — — 20,000 20,000 20,000 Subtotal — — 885,994 885,994 885,994 Long-term investments: Corporate bonds — — — — — Subtotal — — — — — Total $ 91,846 $ 91,846 $ 1,118,691 $ 1,118,691 $ 1,210,537 (1) As of June 30, 2016 and December 31, 2015, the Company did not record any OTTI on these assets.

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	6 Months Ended
	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Schedule of Property, Plant, and Equipment	Property, plant, and equipment is stated at cost less accumulated depletion/depreciation/amortization and consisted of the following: Estimated Useful Life (Years) June 30, 2016 December 31, 2015 ($ in thousands) Oil and Gas Properties: Proved properties: Well and development costs $ 84,157 $ 71,463 Less: accumulated depletion (6,574 ) — Total proved properties 77,584 71,463 Unproved properties: Oil and gas leasehold 330,829 382,976 Less: accumulated valuation allowance (169,217 ) (175,963 ) 161,612 207,013 Exploration wells in process 762,329 615,258 Total unproved properties 923,941 822,271 Total oil and gas properties, net 1,001,526 893,734 Other Property and Equipment: Computer equipment and software 3 8,782 5,350 Office equipment and furniture 3 – 1,349 1,349 Leasehold improvements 3 – 2,150 2,150 12,281 8,849 Less: accumulated depreciation and amortization (7,533 ) (6,647 ) Total other property and equipment, net 4,748 2,202 Property, plant, and equipment, net $ 1,006,274 $ 895,936
Schedule of Unproved Property Acquisition Costs, Net of Valuation Allowance	As of June 30, 2016 and December 31, 2015, the Company has the following unproved property acquisition costs, net of valuation allowance on the consolidated balance sheets: June 30, 2016 December 31, 2015 ($ in thousands) Individual oil and gas leaseholds with carrying value greater than $1 million $ 255,203 $ 305,270 Individual oil and gas leaseholds with carrying value less than $1 million 75,626 77,706 330,829 382,976 Accumulated valuation allowance (169,217 ) (175,963 ) Total oil and gas leasehold $ 161,612 $ 207,013
Schedule of Net Changes in Capitalized Exploration Well Costs	The following tables reflect the Company’s net changes in and the cumulative costs of capitalized exploration well costs (excluding any related leasehold costs): June 30, 2016 December 31, 2015 ($ in thousands) Beginning of period $ 615,258 $ 330,099 Additions to capitalized exploration Exploration well costs 236,069 285,118 Capitalized interest 22,621 24,161 Reclassifications to wells, facilities, and equipment based on determination of proved reserves — — Amounts charged to expense(1) (111,619 ) (24,120 ) End of period $ 762,329 $ 615,258 (1) The amounts of $111.6 million for the six months ended June 30, 2016 and $24.1 million for the year ended December 31, 2015, represents impairment charges on exploration wells drilled in the U.S. Gulf of Mexico which did not encounter commercial hydrocarbons.
Schedule of Cumulative Costs of Capitalized Exploration Well Costs	June 30, 2016 December 31, 2015 ($ in thousands) Cumulative costs: Exploration well costs $ 701,144 $ 576,694 Capitalized interest 61,185 38,564 $ 762,329 $ 615,258 Well costs capitalized for a period greater than one year after completion of drilling (included in table above) $ 362,187 $ 351,753

Other Assets (Tables)

Other Assets (Tables)	6 Months Ended
	Jun. 30, 2016
Other Assets [Abstract]
Schedule of Other Assets	As of June 30, 2016 and December 31, 2015, the balance in other assets consisted of the following: June 30, 2016 December 31, 2015 (in thousands) Debt issue costs(1) $ — $ 3,595 Rig costs(2) 8,331 15,397 Other deposits 500 — $ 8,831 $ 18,992 (1) As of June 30, 2016 and December 31, 2015, the $0 million and $3.6 million, respectively, in debt issue costs was related to the issuance of the Borrowing Base Facility Agreement, as described in Note 9. On June 17, 2016, the Company terminated the Borrowing Base Facility Agreement and all associated costs were written off. (2) As of June 30, 2016 and December 31, 2015, the $8.3 million and $15.4 million, respectively, relate to costs associated with the Rowan Reliance drilling rig which is currently drilling in U.S. Gulf of Mexico. These costs are capitalized to the wells over the term of the respective drilling rig contracts.

Long-term Debt (Tables)

Long-term Debt (Tables)	6 Months Ended
	Jun. 30, 2016
Long Term Debt [Abstract]
Schedule of The Carrying Amounts of The Liability Components of The Notes	The carrying amounts of the liability components of the Notes were as follows: June 30, 2016 December 31, 2015 Principal Amount Unamortized discount and debt issuance costs (1) Carrying Amount Principal Amount Unamortized discount and debt issuance costs Carrying Amount ($ in thousands) Carrying amount of liability component 2.625% Notes $ 1,380,000 $ (229,048 ) $ 1,150,952 $ 1,380,000 $ (258,565 ) $ 1,121,435 3.125% Notes 1,300,000 (420,231 ) 879,769 1,300,000 (439,540 ) 860,460 Total $ 2,680,000 $ (649,279 ) $ 2,030,721 $ 2,680,000 $ (698,105 ) $ 1,981,895 (1) Unamortized discount and debt issuance costs will be amortized over the remaining life of the Notes which is 3.5 years for the 2.625% Notes and 8.0 years for the 3.125% Notes. See Note 1 related to a change in the classification of unamortized debt issuance costs on the Condensed Consolidated Balance Sheets.
Schedule of Carrying Amounts of The Equity Components of The Notes	The carrying amounts of the equity components of the Notes were as follows: June 30, 2016 December 31, 2015 ($ in thousands) Debt discount relating to value of conversion option $ 866,340 $ 866,340 Debt issue costs (20,185 ) (20,185 ) Total $ 846,155 $ 846,155
Schedule of The Fair Value of The Notes Excluding The Conversion Feature	As of June 30, 2016 and December 31, 2015, the fair values of the Notes were as follows: June 30, 2016 December 31, 2015 ($ in thousands) 2.625% Notes $ 503,700 $ 793,500 3.125% Notes 432,276 640,250 Total $ 935,976 $ 1,433,750

Angola Transaction (Tables)

Angola Transaction (Tables)	6 Months Ended
	Jun. 30, 2016
Discontinued Operations And Disposal Groups [Abstract]
Summary of Assets and Liabilities and Operation Results Associated with Blocks 9, 20, and 21 Offshore Angola	The following table summarizes the assets and liabilities associated with Blocks 9, 20, and 21 offshore Angola. Although the Company relinquished its working interest in Block 9 on February 29, 2016, the Company continues to have assets and liabilities associated with the entity. The Company continues to assess the balances for possible impairment as the assets and liabilities held for sale are required to be presented at fair value. There has been no impairment identified to date. June 30, 2016 December 31, 2015 ($ in thousands) Cash and cash equivalents $ 43,527 $ 8,578 Joint interest and other receivables 159,542 156,599 Prepaid expenses and other current assets 5,025 8,216 Inventory 43,147 56,224 Short term restricted funds — 22,538 Oil and gas properties 1,611,828 1,465,299 Other property and equipment, net 10,107 10,107 Long term restricted funds — 82,568 Other assets 338 922 Total assets of the discontinued operation 1,873,514 1,811,051 Trade and other accounts payable (20,528 ) (6,089 ) Accrued liabilities (81,415 ) (128,259 ) Short term contractual obligations (92,076 ) (115,110 ) Long term contractual obligations (2,688 ) (1,381 ) Other long term liabilities — — Total liabilities of the discontinued operation $ (196,707 ) $ (250,839 )
Results for Blocks 9, 20, and 21 Offshore Angola Classified within Discontinued Operations	Results for Blocks 9, 20, and 21 offshore Angola classified within discontinued operations consisted of the following: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Seismic and exploration $ 3,093 $ 5,646 $ 10,410 $ 9,348 Dry hole expense and impairment (1,677 ) 611 1,874 611 General and administrative 3,688 6,258 13,009 12,778 Depreciation and amortization — 926 — 1,856 Gain on the release of letters of credit (1) — — (4,375 ) — Net loss from discontinued operations $ 5,104 $ 13,441 $ 20,918 $ 24,593 (1) Amount represents the gain recognized on the release of the Block 9 letter of credit that was previously written off.

Seismic and Exploration Expen33

Seismic and Exploration Expenses (Tables)	6 Months Ended
	Jun. 30, 2016
Oil And Gas Exploration And Production Industries Disclosures [Abstract]
Schedule of Seismic and Exploration Expenses	Seismic and exploration expenses consisted of the following: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Seismic costs $ 3,024 $ 7,970 $ 570 $ 19,801 Leasehold delay rentals 3,297 2,936 4,561 4,327 Other exploration expense 14 361 (50 ) 1,206 $ 6,335 $ 11,267 $ 5,081 $ 25,334

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Schedule of Changes in Asset Retirement Obligation (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Changes in asset retirement obligation
Beginning of period	$ 3,167
Liabilities incurred	0
Accretion	204
End of period	$ 3,371

Summary of Significant Accoun35

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)shares	Jun. 30, 2015shares	Jun. 30, 2016USD ($)segmentshares	Jun. 30, 2015shares	Dec. 31, 2015USD ($)	Aug. 22, 2015	Mar. 31, 2015	May 13, 2014	Dec. 17, 2012
Description of Operations
Percentage of working interest acquired							9.375%
Number of reportable segment | segment			1
Reclassification of unamortized debt issuance costs					$ 3,595,000
Investments
OTTI in debt securities	$ 0		$ 0		0
Earnings (Loss) Per Share
Weighted average number of shares outstanding, basic | shares	409,920,869		409,590,679
Shares of non-vested restricted stock, non vested restricted stock units, outstanding stock options and 2.625% convertible senior notes due 2019 and 3.125% convertible senior notes due 2024, excluded from the diluted loss per share calculation | shares	8,808,708	9,967,516	8,808,708	9,967,516
2.625% convertible senior notes due 2019
Earnings (Loss) Per Share
Interest rate (as a percent)	2.625%	2.625%	2.625%	2.625%					2.625%
3.125% convertible senior notes due 2024
Earnings (Loss) Per Share
Interest rate (as a percent)	3.125%	3.125%	3.125%	3.125%				3.125%
New Accounting Pronouncement Early Adoption Effect
Description of Operations
Reclassification of unamortized debt issuance costs					$ 32,900,000
Impairment charges related to Heidelberg field
Description of Operations
Reduction of impairment charges related to prior year			$ 8,500,000
Discontinued operations held for sale | Block 20, offshore Angola | CIE Angola Block 20 Ltd
Description of Operations
Percentage of working interest acquired						40.00%
Discontinued operations held for sale | Block 21, offshore Angola | CIE Angola Block 21 Ltd
Description of Operations
Percentage of working interest acquired						40.00%

Cash and Cash Equivalents - Cas

Cash and Cash Equivalents - Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Cash And Cash Equivalents [Abstract]
Cash at banks	$ 22,918	$ 33,173
Money market funds	23,064
Held-to-maturity securities	85,679	38,420
Total	$ 131,661	$ 71,593	$ 138,074	$ 246,705

Restricted Cash and Cash Equi37

Restricted Cash and Cash Equivalents and Investments - Schedule of Restricted Cash and Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents and Investments
Restricted cash and cash equivalents and investments	$ 252,200	$ 252,950
Angolan sale proceeds
Restricted Cash and Cash Equivalents and Investments
Restricted cash and cash equivalents and investments	250,000	250,000
American Express Bank pledge agreement
Restricted Cash and Cash Equivalents and Investments
Restricted cash and cash equivalents and investments		750
Citibank commercial card agreement
Restricted Cash and Cash Equivalents and Investments
Restricted cash and cash equivalents and investments	$ 2,200	$ 2,200

Restricted Cash and Cash Equi38

Restricted Cash and Cash Equivalents and Investments - Schedule of Restricted Cash and Cash Equivalents and Investments (Parenthetical) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Restricted Cash and Cash Equivalents and Investments
Restricted cash and cash equivalents and investments	$ 252,200	$ 252,950
Angolan sale proceeds
Restricted Cash and Cash Equivalents and Investments
Consideration received			$ 250,000
Restricted cash and cash equivalents and investments	250,000	$ 250,000
American Express Bank And Citibank Pledge Agreement
Restricted Cash and Cash Equivalents and Investments
Collateral held	$ 2,200

Joint Interest and Other Rece39

Joint Interest and Other Receivables - Additional Information (Details)	6 Months Ended
	Jun. 30, 2016
Receivables [Abstract]
Settlement period for bills under operating agreements	30 days

Joint Interest and Other Rece40

Joint Interest and Other Receivables - Schedule of Joint Interest, Revenue and Other Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Joint Interest and Other Receivables
Receivable attributable to joint interest partners	$ 48,932	$ 54,709
Revenue receivable	1,909
Accrued interest on investment securities	1,005	3,567
Other	595	376
Partners in the U.S. Gulf of Mexico
Joint Interest and Other Receivables
Receivable attributable to joint interest partners	$ 45,423	$ 50,766

Investments - Schedule of Fair

Investments - Schedule of Fair Value of Held-to-maturity Securities Recorded at Amortized Cost (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 738,305	$ 1,118,691
Corporate securities
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	120,501	492,955
U.S. Treasury securities
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	91,421
Commercial paper
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 526,383	604,986
Certificates of deposit
Schedule Of Held To Maturity Securities [Line Items]
Fair market value		$ 20,750

Investments - Schedule of Held-

Investments - Schedule of Held-to-maturity Securities Included in the Company's Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 738,305	$ 1,118,691
Cash and cash equivalents
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	85,679	38,420
Short-term investments
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	440,866	885,994
Restricted cash and cash equivalents and investments
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	202,716	$ 194,277
Long-term restricted funds
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 9,044

Investments - Schedule of Contr

Investments - Schedule of Contractual Maturities of Held-to-maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Held-to-maturities, Carrying value
Within 1 year	$ 738,305	$ 1,118,691
Total	738,305	1,118,691
Held-to-maturity securities, Estimated fair value
Within 1 year	738,305	1,118,691
Total	$ 738,305	$ 1,118,691

Fair Value Measurements - Signi

Fair Value Measurements - Significant Financial Instruments Measured on a Recurring Basis as Categorized by the Fair Value Measurement Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	$ 131,661	$ 71,593	$ 138,074	$ 246,705
Restricted cash and cash equivalents and investments	252,200	252,950
Short-term investments	440,866	885,994
Long-term restricted funds	9,044
Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	131,661	71,593
Restricted cash and cash equivalents and investments	252,200	252,950
Short-term investments	440,866	885,994
Long-term restricted funds	9,044
Total	833,771	1,210,537
Level 1 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	45,982	33,173
Restricted cash and cash equivalents and investments	49,484	58,673
Total	95,466	91,846
Level 1 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	45,982	33,173
Restricted cash and cash equivalents and investments	49,484	58,673
Total	95,466	91,846
Level 2 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	85,679	38,420
Restricted cash and cash equivalents and investments	202,716	194,277
Short-term investments	440,866	885,994
Long-term restricted funds	9,044
Total	738,305	1,118,691
Level 2 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	85,679	38,420
Restricted cash and cash equivalents and investments	202,716	194,277
Short-term investments	440,866	885,994
Long-term restricted funds	9,044
Total	738,305	1,118,691
Cash | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	22,918	33,173
Cash | Level 1 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	22,918	33,173
Cash | Level 1 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	22,918	33,173
Money market funds | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	23,064
Restricted cash and cash equivalents and investments	49,484	58,673
Money market funds | Level 1 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	23,064
Restricted cash and cash equivalents and investments	49,484	58,673
Money market funds | Level 1 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	23,064
Restricted cash and cash equivalents and investments	49,484	58,673
Commercial paper | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	85,679	38,420
Restricted cash and cash equivalents and investments	82,215	188,517
Short-term investments	358,489	378,048
Commercial paper | Level 2 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	85,679	38,420
Restricted cash and cash equivalents and investments	82,215	188,517
Short-term investments	358,489	378,048
Commercial paper | Level 2 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Cash and cash equivalents	85,679	38,420
Restricted cash and cash equivalents and investments	82,215	188,517
Short-term investments	358,489	378,048
Corporate securities | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments	120,501	5,010
Short-term investments		487,946
Corporate securities | Level 2 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments	120,501	5,010
Short-term investments		487,946
Corporate securities | Level 2 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments	120,501	5,010
Short-term investments		487,946
Certificates of deposit | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments		750
Short-term investments		20,000
Certificates of deposit | Level 2 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments		750
Short-term investments		20,000
Certificates of deposit | Level 2 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Restricted cash and cash equivalents and investments		750
Short-term investments		$ 20,000
U.S. Treasury securities | Recurring basis
Significant financial instruments as categorized by the fair value measurement hierarchy
Short-term investments	82,377
Long-term restricted funds	9,044
U.S. Treasury securities | Level 2 | Recurring basis | Carrying Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Short-term investments	82,377
Long-term restricted funds	9,044
U.S. Treasury securities | Level 2 | Recurring basis | Fair Value
Significant financial instruments as categorized by the fair value measurement hierarchy
Short-term investments	82,377
Long-term restricted funds	$ 9,044

Property, Plant, and Equipmen45

Property, Plant, and Equipment - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Property, Plant, and Equipment
Well and development costs	$ 84,157	$ 71,463
Less: accumulated depletion	(6,574)	0
Total proved properties	77,584	71,463
Oil and gas leasehold	330,829	382,976
Less: accumulated valuation allowance	(169,217)	(175,963)
Total oil and gas leasehold	161,612	207,013
Total unproved properties	923,941	822,271
Total oil and gas properties, net	1,001,526	893,734
Other Property and Equipment	12,281	8,849
Less: accumulated depreciation and amortization	(7,533)	(6,647)
Total other property and equipment, net	4,748	2,202
Total property, plant, and equipment, net	1,006,274	895,936
Exploration wells in process
Property, Plant, and Equipment
Total unproved properties	$ 762,329	615,258
Computer equipment and software
Property, Plant, and Equipment
Estimated Useful Life	3 years
Other Property and Equipment	$ 8,782	5,350
Office equipment and furniture
Property, Plant, and Equipment
Other Property and Equipment	$ 1,349	1,349
Office equipment and furniture | Minimum
Property, Plant, and Equipment
Estimated Useful Life	3 years
Office equipment and furniture | Maximum
Property, Plant, and Equipment
Estimated Useful Life	5 years
Leasehold improvements
Property, Plant, and Equipment
Other Property and Equipment	$ 2,150	$ 2,150
Leasehold improvements | Minimum
Property, Plant, and Equipment
Estimated Useful Life	3 years
Leasehold improvements | Maximum
Property, Plant, and Equipment
Estimated Useful Life	10 years

Property, Plant, and Equipmen46

Property, Plant, and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Mar. 31, 2015
Property, Plant, and Equipment
Depletion, depreciation and amortization	$ 4,290	$ 367	$ 7,459	$ 779
Percentage of working interest acquired						9.375%
Well and development costs	84,157		84,157		$ 71,463
Exploration well costs
Property, Plant, and Equipment
Well and development costs	102,400		102,400		104,000
Development well costs
Property, Plant, and Equipment
Well and development costs	$ 219,900		$ 219,900		$ 221,200

Property, Plant, and Equipmen47

Property, Plant, and Equipment - Schedule of Unproved Property Acquisition Costs, Net of Valuation Allowance (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Unproved property acquisition costs, net of valuation allowance
Individual oil and gas leaseholds with carrying value greater than $1 million	$ 255,203	$ 305,270
Individual oil and gas leaseholds with carrying value less than $1 million	75,626	77,706
Unproved property	330,829	382,976
Accumulated valuation allowance	(169,217)	(175,963)
Total oil and gas leasehold	$ 161,612	$ 207,013

Property, Plant, and Equipmen48

Property, Plant, and Equipment - Schedule of Unproved Property Acquisition Costs, Net of Valuation Allowance (Parenthetical) (Details) $ in Millions	Jun. 30, 2016USD ($)
Unproved property acquisition costs, net of valuation allowance
Upper limit of individual leasehold	$ 1
Lower limit of individual leasehold	$ 1

Property, Plant, and Equipmen49

Property, Plant, and Equipment - Schedule of Net Changes in Capitalized Exploration Well Costs (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period	$ 615,258	$ 330,099
Amounts charged to expense	(111,619)	(24,120)
End of period	762,329	615,258
Exploration well costs
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period	576,694
Additions to capitalized exploration	236,069	285,118
End of period	701,144	576,694
Capitalized interest
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period	38,564
Additions to capitalized exploration	22,621	24,161
End of period	$ 61,185	$ 38,564

Property, Plant, and Equipmen50

Property, Plant, and Equipment - Schedule of Net Changes in Capitalized Exploration Well Costs (Parenthetical) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Amounts charged to expense	$ 111,619	$ 24,120
U.S. Gulf of Mexico
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Amounts charged to expense	$ 111,600	$ 24,100

Property, Plant, and Equipmen51

Property, Plant, and Equipment - Schedule of Cumulative Costs of Capitalized Exploration Well Costs (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	$ 762,329	$ 615,258	$ 330,099
Well costs capitalized for a period greater than one year after completion of drilling	362,187	351,753
Exploration well costs
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	701,144	576,694
Capitalized interest
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	$ 61,185	$ 38,564

Other Assets - Schedule of Othe

Other Assets - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Other Assets [Abstract]
Debt issue costs		$ 3,595
Rig costs	$ 8,331	15,397
Other deposits	500
Other assets	$ 8,831	$ 18,992

Other Assets - Schedule of Ot53

Other Assets - Schedule of Other Assets (Parenthetical) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Other Assets [Abstract]
Debt issue cost	$ 0	$ 3,600
Termination of borrowing base facility agreement	Jun. 17, 2016
Rig costs	$ 8,331	$ 15,397

Long-term Debt - Additional Inf

Long-term Debt - Additional Information (Details) $ / shares in Units, item in Millions	May 13, 2014USD ($)item$ / shares	Dec. 17, 2012USD ($)item$ / shares	Jun. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)$ / shares	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Jun. 17, 2016USD ($)
Debt instrument
Accrued for interest			$ 7,800,000	$ 7,800,000		$ 7,800,000
Interest expense, net of capitalized amount				$ 16,000,000	$ 17,800,000	$ 31,600,000	$ 37,900,000
Debt Issuance Costs Allocated to Liability Component								$ 233,600,000
Notes
Debt instrument
Repurchase price as a percentage of principal amount of debt instrument		100.00%
Specified minimum percentage of principal amount, the holders of which may declare all principal, accrued and unpaid interest to be due and payable immediately, upon the occurrence of an Event of Default		25.00%
Percentage of principal amount, which may be declared by holders of a specified principal amount to be due and payable immediately upon occurrence of an Event of Default		100.00%
2.625% convertible senior notes due 2019
Debt instrument
Interest rate (as a percent)		2.625%	2.625%	2.625%	2.625%	2.625%	2.625%
Aggregate principal amount of notes issued		$ 1,380,000,000
Initial conversion rate of common stock		28.023
Initial conversion price per share of common stock (in dollars per share) | $ / shares		$ 35.68
Number of underlying shares that the holder of the debt instrument would receive upon conversion | item		38.7
Effective interest rate used to amortize liability component of debt issue costs (as a percent)		8.40%
Debt Issuance Costs Allocated to Liability Component						$ 217,500,000
3.125% convertible senior notes due 2024
Debt instrument
Interest rate (as a percent)	3.125%		3.125%	3.125%	3.125%	3.125%	3.125%
Aggregate principal amount of notes issued	$ 1,300,000,000
Initial conversion rate of common stock	43.3604
Initial conversion price per share of common stock (in dollars per share) | $ / shares	$ 23.06
Number of underlying shares that the holder of the debt instrument would receive upon conversion | item	56.4
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable						20 days
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable						30 days
Minimum sale price of common stock to determine eligibility of conversion | $ / shares						$ 30
Number of business days after any five consecutive trading day period during the note measurement period						5 days
Number of consecutive trading days before five consecutive business days during the note measurement period						5 days
Convertibility of debt, trading price of debt test, percentage of closing price of stock used in calculation						98.00%
Effective interest rate used to amortize liability component of debt issue costs (as a percent)	8.97%
Facility Agreement | GOM#1
Debt instrument
Maximum borrowing capacity									$ 150,000,000
Borrowings under facility									0
Prepayment fees payable									$ 0
Write off of debt issuance cost			$ 3,300,000

Long-term Debt - Schedule of Th

Long-term Debt - Schedule of The Carrying Amounts of The Liability Components of The Notes (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Debt instrument
Principal Amount	$ 2,680,000	$ 2,680,000
Unamortized discount and debt issuance costs	(649,279)	(698,105)
Carrying Amount	2,030,721	1,981,895
2.625% Notes
Debt instrument
Principal Amount	1,380,000	1,380,000
Unamortized discount and debt issuance costs	(229,048)	(258,565)
Carrying Amount	1,150,952	1,121,435
3.125% Notes
Debt instrument
Principal Amount	1,300,000	1,300,000
Unamortized discount and debt issuance costs	(420,231)	(439,540)
Carrying Amount	$ 879,769	$ 860,460

Long-term Debt - Schedule of 56

Long-term Debt - Schedule of The Carrying Amounts of The Liability Components of The Notes (Parenthetical) (Details)	6 Months Ended
	Jun. 30, 2016
2.625% Notes
Debt instrument
Remaining term of debt	3 years 6 months
3.125% Notes
Debt instrument
Remaining term of debt	8 years

Long-term Debt -Schedule of Car

Long-term Debt -Schedule of Carrying Amounts of The Equity Components of The Notes (Details) - Notes - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Debt instrument
Debt discount relating to value of conversion option	$ 866,340	$ 866,340
Debt issue costs	(20,185)	(20,185)
Total	$ 846,155	$ 846,155

Long-term Debt - Schedule of 58

Long-term Debt - Schedule of The Fair Value of The Notes Excluding The Conversion Feature (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Notes
Debt instrument
Fair value of the notes excluding conversion feature	$ 935,976	$ 1,433,750
2.625% Notes
Debt instrument
Fair value of the notes excluding conversion feature	503,700	793,500
3.125% Notes
Debt instrument
Fair value of the notes excluding conversion feature	$ 432,276	$ 640,250

Angola Transaction - Additional

Angola Transaction - Additional Information (Details) - USD ($)	Aug. 22, 2015	Jun. 30, 2016	Jul. 26, 2016	Mar. 31, 2015
Angola Transaction
Percentage of working interest acquired				9.375%
Discontinued operations held for sale | Block 20, offshore Angola | CIE Angola Block 20 Ltd
Angola Transaction
Percentage of working interest acquired	40.00%
Discontinued operations held for sale | Block 21, offshore Angola | CIE Angola Block 21 Ltd
Angola Transaction
Percentage of working interest acquired	40.00%
Discontinued operations held for sale | Block 20 and Block 21 | First Payment | Subsequent Event
Angola Transaction
Consideration			$ 158,600,000
Discontinued operations held for sale | Block 20 and Block 21 | CIE Angola block 20 and block 21
Angola Transaction
Consideration	$ 1,750,000,000
Withholding taxes for the gross consideration to be paid	19,700,000
Discontinued operations held for sale | Block 20 and Block 21 | CIE Angola block 20 and block 21 | First Payment
Angola Transaction
Consideration	$ 250,000,000
Discontinued operations held for sale | Block 9, Block 20 And Block 21, Offshore Angola
Angola Transaction
Impairment		$ 0
Sonangol Pesquisa e Producao, S.A | Block 20, offshore Angola | CIE Angola Block 20 Ltd
Angola Transaction
Percentage of working interest acquired	30.00%
Sonangol Pesquisa e Producao, S.A | Block 21, offshore Angola | CIE Angola Block 21 Ltd
Angola Transaction
Percentage of working interest acquired	60.00%

Angola Transaction - Summary of

Angola Transaction - Summary of Assets and Liabilities and Operation Results Associated with Blocks 9, 20, and 21 Offshore Angola (Details) - Discontinued operations held for sale - Block 9, Block 20 And Block 21, Offshore Angola - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Angola Transaction
Cash and cash equivalents	$ 43,527	$ 8,578
Joint interest and other receivables	159,542	156,599
Prepaid expenses and other current assets	5,025	8,216
Inventory	43,147	56,224
Short term restricted funds		22,538
Oil and gas properties	1,611,828	1,465,299
Other property and equipment, net	10,107	10,107
Long term restricted funds		82,568
Other assets	338	922
Total assets of the discontinued operation	1,873,514	1,811,051
Trade and other accounts payable	(20,528)	(6,089)
Accrued liabilities	(81,415)	(128,259)
Short term contractual obligations	(92,076)	(115,110)
Long term contractual obligations	(2,688)	(1,381)
Total liabilities of the discontinued operation	$ (196,707)	$ (250,839)

Angola Transaction - Summary 61

Angola Transaction - Summary of Results for Blocks 9, 20, and 21 Offshore Angola Classified Within Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Angola Transaction
Loss from discontinued operations	$ 5,104	$ 13,441	$ 20,918	$ 24,593
Discontinued operations held for sale | Block 9, Block 20 And Block 21, Offshore Angola
Angola Transaction
Seismic and exploration	3,093	5,646	10,410	9,348
Dry hole expense and impairment	(1,677)	611	1,874	611
General and administrative	3,688	6,258	13,009	12,778
Depreciation and amortization		926		1,856
Gain on the release of letters of credit			(4,375)
Loss from discontinued operations	$ 5,104	$ 13,441	$ 20,918	$ 24,593

Seismic and Exploration Expen62

Seismic and Exploration Expenses - Schedule of Seismic and Exploration Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Oil And Gas Exploration And Production Industries Disclosures [Abstract]
Seismic costs	$ 3,024	$ 7,970	$ 570	$ 19,801
Leasehold delay rentals	3,297	2,936	4,561	4,327
Other exploration expense	14	361	(50)	1,206
Total seismic and exploration expenses	$ 6,335	$ 11,267	$ 5,081	$ 25,334

Equity Based Compensation - Add

Equity Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 18, 2016	Feb. 20, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Apr. 30, 2015
Equity Based Compensation
Equity based compensation			$ (4,900)	$ 7,100	$ 2,826	$ 12,981
Common stock, shares issued			410,054,961		410,054,961		408,740,182
2015 Long Term Incentive Plan (the "2015 Plan")
Equity Based Compensation
Awards granted (in shares)					1,851,372
Common Stock | 2015 Long Term Incentive Plan (the "2015 Plan")
Equity Based Compensation
Shares available for grant under the plan								12,000,000
Restricted Stock
Equity Based Compensation
Granted (in shares)					571,428
Restricted Stock | Two Senior Officers
Equity Based Compensation
Granted (in shares)					571,428
Restricted Stock Units
Equity Based Compensation
Granted (in shares)					3,491,352
Restricted Stock Units | 2015 Long Term Incentive Plan (the "2015 Plan")
Equity Based Compensation
Awards granted (in shares)	3,491,352
Market price per share	$ 2.44
Grant date fair value of RSU's	$ 10,400
Stock compensation expense			$ 1,300	0	$ 1,300	0
Restricted Stock Units | 2015 Long Term Incentive Plan (the "2015 Plan") | Vesting Yearly Installment One
Equity Based Compensation
RSU's vesting date	Mar. 1, 2017
Restricted Stock Units | 2015 Long Term Incentive Plan (the "2015 Plan") | Vesting Yearly Installment Two
Equity Based Compensation
RSU's vesting date	Mar. 1, 2018
Restricted Stock Units | 2015 Long Term Incentive Plan (the "2015 Plan") | Vesting Yearly Installment Three
Equity Based Compensation
RSU's vesting date	Mar. 1, 2019
Restricted Stock Units | Non-employee Directors
Equity Based Compensation
Awards granted (in shares)					362,934
Stock Options
Equity Based Compensation
Granted (in shares)					1,129,944
Stock Options | Two Senior Officers
Equity Based Compensation
Granted (in shares)					1,129,944
Retainer Awards | Non-employee Directors | Common Stock
Equity Based Compensation
Awards granted (in shares)					82,898
Stock Appreciation Rights ("SARs") | Long Term Incentive Plan
Equity Based Compensation
Market price per share		$ 8.87
Stock compensation expense			$ 100	$ 400	$ 600	$ 900
Common stock, shares issued		1,526,835
Vesting period		3 years
Fair value price per share		$ 4.53	$ 2.74		$ 2.74
Reduction in aggregate fair value					$ (1,300)
Stock Appreciation Rights ("SARs") | Long Term Incentive Plan | Vesting in one year
Equity Based Compensation
SARs vesting percentage		0.33%
Stock Appreciation Rights ("SARs") | Long Term Incentive Plan | Vesting in two years
Equity Based Compensation
SARs vesting percentage		0.33%
Stock Appreciation Rights ("SARs") | Long Term Incentive Plan | Vesting in three years
Equity Based Compensation
SARs vesting percentage		0.33%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 0
Unrecognized tax benefits	$ 0	$ 0	$ 0

Other Matters - Additional Info

Other Matters - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Legal Proceedings Disclosure [Abstract]
Severance costs associated with workforce reduction plan	$ 3	$ 6.1