10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Quarterly Period Ended June 30, 2015

OR

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission file number 001-35054

Marathon Petroleum Corporation

(Exact name of registrant as specified in its charter)

Delaware	27-1284632
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
539 South Main Street, Findlay, Ohio	45840-3229
(Address of principal executive offices)	(Zip code)

(419) 422-2121

(Registrant’s telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files.) Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer	x	Accelerated filer	¨
Non-accelerated filer	¨  (Do not check if a smaller reporting company)	Smaller reporting company	¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act) Yes  ¨    No  x

There were 536,156,786 shares of Marathon Petroleum Corporation common stock outstanding as of July 31, 2015.

MARATHON PETROLEUM CORPORATION

Form 10-Q

Quarter Ended June 30, 2015

INDEX

	Page
PART I – FINANCIAL INFORMATION
Item 1.   Financial Statements:
Consolidated Statements of Income (Unaudited)	2
Consolidated Statements of Comprehensive Income (Unaudited)	3
Consolidated Balance Sheets (Unaudited)	4
Consolidated Statements of Cash Flows (Unaudited)	5
Consolidated Statements of Equity (Unaudited)	6
Notes to Consolidated Financial Statements (Unaudited)	7
Item 2.   Management’s Discussion and Analysis of Financial Condition and Results of Operations	27
Item 3.   Quantitative and Qualitative Disclosures about Market Risk	46
Item 4.   Controls and Procedures	47
Supplementary Statistics (Unaudited)	48
PART II – OTHER INFORMATION
Item 1.    Legal Proceedings	51
Item 1A. Risk Factors	51
Item 2.    Unregistered Sales of Equity Securities and Use of Proceeds	52
Item 6.    Exhibits	53
Signatures	54

Unless otherwise stated or the context otherwise indicates, all references in this Form 10-Q to “MPC,” “us,” “our,” “we” or “the Company” mean Marathon Petroleum Corporation and its consolidated subsidiaries.

1

Part I – Financial Information

Item 1. Financial Statements

Marathon Petroleum Corporation

Consolidated Statements of Income (Unaudited)

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions, except per share data)	2015			2014			2015			2014
Revenues and other income:
Sales and other operating revenues (including consumer excise taxes)	$	20,537		$	26,844		$	37,728		$	50,129
Income from equity method investments	20			57			35			92
Net gain (loss) on disposal of assets	(1		)	11			4			12
Other income	25			21			54			45
Total revenues and other income	20,581			26,933			37,821			50,278
Costs and expenses:
Cost of revenues (excludes items below)	16,366			23,096			29,410			43,636
Purchases from related parties	82			130			158			289
Consumer excise taxes	1,939			1,599			3,771			3,114
Depreciation and amortization	362			325			725			645
Selling, general and administrative expenses	393			316			751			662
Other taxes	104			98			201			202
Total costs and expenses	19,246			25,564			35,016			48,548
Income from operations	1,335			1,369			2,805			1,730
Net interest and other financial income (costs)	(64		)	(48		)	(145		)	(94		)
Income before income taxes	1,271			1,321			2,660			1,636
Provision for income taxes	432			457			918			565
Net income	839			864			1,742			1,071
Less net income attributable to noncontrolling interests	13			9			25			17
Net income attributable to MPC	$	826		$	855		$	1,717		$	1,054
Per Share Data (See Note 7)
Basic:
Net income attributable to MPC per share	$	1.52		$	1.49		$	3.16		$	1.81
Weighted average shares outstanding	541			574			543			580
Diluted:
Net income attributable to MPC per share	$	1.51		$	1.48		$	3.14		$	1.80
Weighted average shares outstanding	544			578			547			584
Dividends paid	$	0.25		$	0.21		$	0.50		$	0.42

The accompanying notes are an integral part of these consolidated financial statements.

2

Marathon Petroleum Corporation

Consolidated Statements of Comprehensive Income (Unaudited)

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Net income	$	839		$	864		$	1,742		$	1,071
Other comprehensive income (loss):
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $7, ($3), $12 and $1	12			(5		)	20			2
Prior service costs, net of tax of ($4), ($4), ($9) and ($9)	(8		)	(8		)	(16		)	(16		)
Other comprehensive income (loss)	4			(13		)	4			(14		)
Comprehensive income	843			851			1,746			1,057
Less comprehensive income attributable to noncontrolling interests	13			9			25			17
Comprehensive income attributable to MPC	$	830		$	842		$	1,721		$	1,040

The accompanying notes are an integral part of these consolidated financial statements.

3

Marathon Petroleum Corporation

Consolidated Balance Sheets (Unaudited)

(In millions, except share data)	June 30, 2015			December 31, 2014
Assets
Current assets:
Cash and cash equivalents	$	1,881		$	1,494
Receivables, less allowance for doubtful accounts of $30 and $13	3,876			4,058
Inventories	5,540			5,642
Other current assets	134			145
Total current assets	11,431			11,339
Equity method investments	994			865
Property, plant and equipment, net	16,283			16,261
Goodwill	1,566			1,566
Other noncurrent assets	379			394
Total assets	$	30,653		$	30,425
Liabilities
Current liabilities:
Accounts payable	$	6,225		$	6,661
Payroll and benefits payable	369			427
Consumer excise taxes payable	469			463
Accrued taxes	517			647
Long-term debt due within one year	780			27
Other current liabilities	365			354
Total current liabilities	8,725			8,579
Long-term debt	5,918			6,575
Deferred income taxes	2,011			2,014
Defined benefit postretirement plan obligations	1,143			1,099
Deferred credits and other liabilities	566			768
Total liabilities	18,363			19,035
Commitments and contingencies (see Note 21)
Equity
MPC stockholders’ equity:
Preferred stock, no shares issued and outstanding (par value $0.01 per share, 30 million shares authorized)	—			—
Common stock:
Issued – 728 million and 726 million shares (par value $0.01 per share, 1 billion shares authorized)	7			7
Held in treasury, at cost – 191 million and 179 million shares	(6,926		)	(6,299		)
Additional paid-in capital	9,912			9,841
Retained earnings	8,959			7,515
Accumulated other comprehensive loss	(309		)	(313		)
Total MPC stockholders’ equity	11,643			10,751
Noncontrolling interests	647			639
Total equity	12,290			11,390
Total liabilities and equity	$	30,653		$	30,425

The accompanying notes are an integral part of these consolidated financial statements.

4

Marathon Petroleum Corporation

Consolidated Statements of Cash Flows (Unaudited)

	Six Months Ended   June 30,
(In millions)	2015			2014
Increase (decrease) in cash and cash equivalents
Operating activities:
Net income	$	1,742		$	1,071
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	725			645
Pension and other postretirement benefits, net	57			109
Deferred income taxes	(12		)	(91		)
Net gain on disposal of assets	(4		)	(12		)
Equity method investments, net	14			(44		)
Changes in the fair value of derivative instruments	18			(2		)
Changes in:
Current receivables	179			(161		)
Inventories	102			(923		)
Current accounts payable and accrued liabilities	(591		)	994
All other, net	(46		)	58
Net cash provided by operating activities	2,184			1,644
Investing activities:
Additions to property, plant and equipment	(764		)	(569		)
Acquisitions	—			(42		)
Disposal of assets	12			17
Investments – acquisitions, loans and contributions	(149		)	(164		)
– redemptions, repayments and return of capital	4			3
All other, net	41			74
Net cash used in investing activities	(856		)	(681		)
Financing activities:
Long-term debt – borrowings	528			270
– repayments	(427		)	(26		)
Debt issuance costs	(4		)	—
Issuance of common stock	26			17
Common stock repurchased	(617		)	(1,148		)
Dividends paid	(272		)	(245		)
Distributions to noncontrolling interests	(18		)	(12		)
Contingent consideration payment	(175		)	—
All other, net	18			14
Net cash used in financing activities	(941		)	(1,130		)
Net increase (decrease) in cash and cash equivalents	387			(167		)
Cash and cash equivalents at beginning of period	1,494			2,292
Cash and cash equivalents at end of period	$	1,881		$	2,125

The accompanying notes are an integral part of these consolidated financial statements.

5

Marathon Petroleum Corporation

Consolidated Statements of Equity (Unaudited)

	MPC Stockholders’ Equity
(In millions)	Common Stock		Treasury Stock			Additional Paid-in Capital		Retained Earnings			Accumulated Other Comprehensive Income (Loss)			Noncontrolling Interests			Total Equity
Balance as of December 31, 2013	$	7	$	(4,155	)	$	9,765	$	5,507		$	(204	)	$	412		$	11,332
Net income	—		—			—		1,054			—			17			1,071
Dividends declared	—		—			—		(245		)	—			—			(245		)
Distributions to noncontrolling interests	—		—			—		—			—			(12		)	(12		)
Other comprehensive loss	—		—			—		—			(14		)	—			(14		)
Shares repurchased	—		(1,148		)	—		—			—			—			(1,148		)
Shares issued (returned) – stock-based compensation	—		(10		)	17		—			—			—			7
Stock-based compensation	—		—			37		—			—			—			37
Other	—		—			—		9			—			—			9
Balance as of June 30, 2014	$	7	$	(5,313	)	$	9,819	$	6,325		$	(218	)	$	417		$	11,037
Balance as of December 31, 2014	$	7	$	(6,299	)	$	9,841	$	7,515		$	(313	)	$	639		$	11,390
Net income	—		—			—		1,717			—			25			1,742
Dividends declared	—		—			—		(273		)	—			—			(273		)
Distributions to noncontrolling interests	—		—			—		—			—			(18		)	(18		)
Other comprehensive income	—		—			—		—			4			—			4
Shares repurchased	—		(617		)	—		—			—			—			(617		)
Shares issued (returned) – stock-based compensation	—		(10		)	26		—			—			—			16
Stock-based compensation	—		—			45		—			—			—			45
Issuance of MPLX LP common units	—		—			—		—			—			1			1
Balance as of June 30, 2015	$	7	$	(6,926	)	$	9,912	$	8,959		$	(309	)	$	647		$	12,290
(Shares in millions)	Common Stock		Treasury Stock
Balance as of December 31, 2013	724		(130		)
Shares repurchased	—		(27		)
Shares issued – stock-based compensation	2		—
Balance as of June 30, 2014	726		(157		)
Balance as of December 31, 2014	726		(179		)
Shares repurchased	—		(12		)
Shares issued – stock-based compensation	2		—
Balance as of June 30, 2015	728		(191		)

The accompanying notes are an integral part of these consolidated financial statements.

6

Notes to Consolidated Financial Statements (Unaudited)

1. Description of the Business and Basis of Presentation

Description of the Business—Our business consists of refining and marketing, retail marketing and pipeline transportation operations conducted primarily in the Midwest, Gulf Coast, East Coast and Southeast regions of the United States, through subsidiaries, including Marathon Petroleum Company LP, Speedway LLC and its subsidiaries (“Speedway”) and MPLX LP and its subsidiaries (“MPLX”).

See Note 9 for additional information about our operations.

Basis of Presentation—All significant intercompany transactions and accounts have been eliminated.

These interim consolidated financial statements are unaudited; however, in the opinion of our management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal, recurring nature unless otherwise disclosed. These interim consolidated financial statements, including the notes, have been prepared in accordance with the rules of the Securities and Exchange Commission applicable to interim period financial statements and do not include all of the information and disclosures required by United States generally accepted accounting principles (“U.S. GAAP”) for complete financial statements.

These interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2014. The results of operations for the three and six months ended June 30, 2015 are not necessarily indicative of the results to be expected for the full year.

We completed a two-for-one stock split in June 2015. All historical share and per share data included in this report has been retroactively restated on a post-split basis. Additionally, we adopted the updated Financial Accounting Standards Board (“FASB”) debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented.

2. Accounting Standards

Recently Adopted

In April 2015, the FASB issued an accounting standards update to simplify the presentation of debt issuance costs. The update requires that debt issue costs for term debt are to be presented on the balance sheet as a direct reduction of the term debt liability as opposed to a deferred charge within other noncurrent assets. The change is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Retrospective application is required and early adoption is permitted. Our adoption of this standard in the second quarter of 2015 did not have a material impact on our consolidated results of operations, financial position or cash flows.

In June 2014, the FASB issued an accounting standards update for the elimination of the concept of development stage entity (“DSE”) from U.S. GAAP and removes the related incremental reporting. The standards update eliminates the additional financial statement requirements specific to a DSE and was adopted in the first quarter of 2015. In addition, the portion of the standard to amend the consolidation model that eliminates the special provisions in the variable interest entity ("VIE") rules for assessing the sufficiency of the equity of a DSE is effective in the first quarter of 2016. Adoption of this standards update in the first quarter of 2015 and 2016 has not and is not expected to have an impact on our consolidated results of operations, financial position or cash flows.

In April 2014, the FASB issued an accounting standards update that redefines the criteria for determining discontinued operations and introduces new disclosures related to these disposals. The updated definition of a discontinued operation is the disposal of a component (or components) of an entity or the classification of a component (or components) of an entity as held for sale that represents a strategic shift for an entity and has (or will have) a major impact on an entity’s operations and financial results. The standard requires disclosure of additional financial information for discontinued operations and individually material components not qualifying for discontinued operation presentation, as well as information regarding an entity’s continuing involvement with the discontinued operation. The accounting standards update was effective prospectively for annual periods beginning on or after December 15, 2014, and interim periods within those years. Adoption of this standards update in the first quarter of 2015 did not impact our consolidated results of operations, financial position or cash flows.

7

Not Yet Adopted

In May 2015, the FASB issued an accounting standard update that eliminates the requirement to categorize in the fair value hierarchy investments that are measured at net asset value using the practical expedient. The standard is effective for fiscal years beginning after December 15, 2015 and interim periods within the fiscal year. Retrospective application is required and early adoption is permitted. While we expect adoption of this standard to affect our fair value hierarchy disclosures, we do not believe it will have an impact on our consolidated results of operations, financial position or cash flows.

In April 2015, the FASB issued an accounting standards update clarifying whether a customer should account for a cloud computing arrangement as an acquisition of a software license or as a service arrangement by providing characteristics that a cloud computing arrangement must have in order to be accounted for as a software license acquisition. The change is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Retrospective or prospective application is allowed and early adoption is permitted. Adoption of this standard is not expected to have a material impact on our consolidated results of operations, financial position or cash flows.

In February 2015, the FASB issued an accounting standards update making targeted changes to the current consolidation guidance. The new standard changes the considerations related to substantive rights, related parties, and decision making fees when applying the VIE consolidation model and eliminates certain guidance for limited partnerships and similar entities under the voting interest consolidation model. The update is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Early adoption is permitted. At this point, we have not determined the impact of the new standards update on our consolidated financial statements and related disclosures. 

In August 2014, the FASB issued an accounting standards update requiring management to assess an entity’s ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. Management will be required to assess if there is substantial doubt about an entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Disclosures will be required if conditions give rise to substantial doubt and the type of disclosure will be determined based on whether management’s plans will be able to alleviate the substantial doubt. The accounting standards update will be effective for the first annual period ending after December 15, 2016, and for annual periods and interim periods thereafter with early application permitted.

In May 2014, the FASB issued an accounting standards update for revenue recognition that is aligned with the International Accounting Standards Board’s revenue recognition standard. The guidance in the update states that revenue is recognized when a customer obtains control of a good or service. Recognition of the revenue will involve a multiple step approach including identifying the contract, identifying the separate performance obligations, determining the transaction price, allocating the price to the performance obligations and then recognizing the revenue as the obligations are satisfied. Additional disclosures will be required to provide adequate information to understand the nature, amount, timing and uncertainty of reported revenues and revenues expected to be recognized. The accounting standards update will be effective on a retrospective or modified retrospective basis for annual reporting periods beginning after December 15, 2017, and interim periods within those years, with early adoption permitted, no earlier than January 1, 2017. We are in the process of determining the impact of the new standard on our consolidated financial statements.

3. MPLX LP

MPLX is a publicly traded master limited partnership that was formed by us to own, operate, develop and acquire pipelines and other midstream assets related to the transportation and storage of crude oil, refined products and other hydrocarbon-based products.

As of June 30, 2015, we owned a 71.5 percent interest in MPLX, including the two percent general partner interest. We consolidate this entity for financial reporting purposes since we have a controlling financial interest, and we record a noncontrolling interest for the interest owned by the public. As of June 30, 2015, MPLX’s assets consisted of a 99.5 percent general partner interest in MPLX Pipe Line Holdings LP (“Pipe Line Holdings”), which owns a network of common carrier crude oil and product pipeline systems and associated storage assets in the Midwest and Gulf Coast regions of the United States. MPLX also owns a 100 percent interest in a butane cavern in Neal, West Virginia.

Sales and Contributions to MPLX

On March 1, 2014, we sold MPLX a 13 percent interest in Pipe Line Holdings for $310 million. MPLX financed this transaction with $40 million of cash on-hand and $270 million of borrowings on its bank revolving credit facility.

On December 1, 2014, we sold and contributed interests in Pipe Line Holdings totaling 30.5 percent to MPLX for $600 million in cash and 2.9 million MPLX common units valued at $200 million. MPLX financed the cash portion of this transaction with $600 million of borrowings on its bank revolving credit facility.

8

The sales and contribution of our interests in Pipe Line Holdings to MPLX resulted in a change in our ownership in Pipe Line Holdings, but not a change in control. We accounted for them as transactions between entities under common control and did not record a gain or loss.

Public Offerings

On December 8, 2014, MPLX completed a public offering of 3.5 million common units at a price to the public of $66.68 per common unit, for aggregate net proceeds of $221 million. MPLX used the net proceeds from this offering to repay borrowings under its bank revolving credit facility and for general partnership purposes. On December 10, 2014, we exercised our right to maintain our two percent general partner interest in MPLX by purchasing 130 thousand general partner units for $9 million.

On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of four percent unsecured senior notes due February 15, 2025 (the “MPLX Senior Notes”). See Note 16 for more information.

4. Acquisitions and Investments

Acquisition of Hess’ Retail Operations and Related Assets

On September 30, 2014, we acquired from Hess Corporation (“Hess”) all of Hess’ retail locations, transport operations and shipper history on various pipelines, including approximately 40,000 barrels per day on Colonial Pipeline for $2.82 billion. We refer to these assets as “Hess’ Retail Operations and Related Assets.” The transaction was funded with a combination of debt and available cash. The transaction provided for an adjustment for working capital, which was finalized during the first quarter of 2015, resulting in a $3 million reduction to our total consideration. This amount is consistent with the estimate we used in prior periods and therefore, the fair value of the assets acquired and liabilities assumed remain unchanged from year-end 2014.

The purchase price allocation resulted in the recognition of $629 million in goodwill by our Speedway segment. The goodwill primarily relates to the expected benefits of a significantly expanded retail platform that should enable growth in new markets, as well as the potential for higher merchandise sales by utilizing Speedway’s marketing approach at the acquired locations. We also expect strategic benefits from the financial and operational scale we expect to realize across our entire retail network. The goodwill is deductible for tax purposes.

The following unaudited pro forma financial information presents consolidated results assuming the acquisition of Hess’ Retail Operations and Related Assets occurred on January 1, 2013. The pro forma financial information does not give effect to potential synergies that could result from the acquisition and is not necessarily indicative of the results of future operations.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions, except per share data)	2014		2014
Sales and other operating revenues (including consumer excise taxes)	$	29,931	$	55,948
Net income attributable to MPC	869		1,051
Net income attributable to MPC per share – basic	$	1.51	$	1.81
Net income attributable to MPC per share – diluted	1.50		1.80

The pro forma information includes adjustments to align accounting policies, an adjustment to depreciation expense to reflect the fair value of property, plant and equipment, increased amortization expense related to identifiable intangible assets, additional interest expense related to financing the acquisition, as well as the related income tax effects.

Acquisition of Biodiesel Facility

On April 1, 2014, we purchased a biodiesel facility in Cincinnati, Ohio from Felda Iffco Sdn Bhd, Malaysia for $40 million. The plant currently produces biodiesel, glycerin and other by-products and has a capacity of approximately 60 million gallons per year.

Neither goodwill nor a gain from a bargain purchase was recognized in conjunction with the acquisition.

Assuming the acquisition had been made at the beginning of any period presented, the consolidated pro forma results would not be materially different from reported results.

9

Investments in Pipeline Companies

In July 2014, we exercised our option to acquire a 35 percent ownership interest in Enbridge Inc.’s Southern Access Extension pipeline (“SAX”) through our investment in Illinois Extension Pipeline Company, LLC (“Illinois Extension Pipeline”). During the six months ended June 30, 2015, we made contributions of $94 million to Illinois Extension Pipeline to fund our portion of the construction costs for the SAX project. We have contributed $214 million since project inception. We account for our ownership interest in Illinois Extension Pipeline as an equity method investment. See Note 21 for information on future contributions to Illinois Extension Pipeline.

In March 2014, we acquired from Chevron Raven Ridge Pipe Line Company an additional seven percent interest in Explorer Pipeline Company (“Explorer”) for $77 million, bringing our ownership interest to 25 percent. As a result of this increase in our ownership, we now account for our investment in Explorer using the equity method of accounting rather than the cost method. The cumulative impact of the change was applied as an adjustment to 2014 retained earnings.

5. Variable Interest Entity

As stated in Note 4, we have a 35 percent ownership interest in Illinois Extension Pipeline. Illinois Extension Pipeline Company LLC is considered a VIE because it is a development stage entity and the equity in the entity is not sufficient to fund the construction of the SAX pipeline. Our maximum exposure to loss due to this VIE at June 30, 2015 was $214 million, which equates to our contributions to-date to fund our portion of the construction costs for the project.

We are not the primary beneficiary of this VIE because we do not have the power to control the activities that significantly influence the economic performance of the entity and, therefore, do not consolidate the entity. The activities that most significantly impact the VIE’s economic performance are the actual construction costs and risks associated with the on-going construction. Through our vote, we have shared power to direct the construction activities, but do not have the sole ability to control the construction activities.

6. Related Party Transactions

Our related parties include:

• Centennial Pipeline LLC (“Centennial”), in which we have a 50 percent noncontrolling interest. Centennial owns a refined products pipeline and storage facility.

• Explorer, in which we have a 25 percent interest. Explorer owns and operates a refined products pipeline.

• LOCAP LLC (“LOCAP”), in which we have a 59 percent noncontrolling interest. LOCAP owns and operates a crude oil pipeline.

• LOOP LLC (“LOOP”), in which we have a 51 percent noncontrolling interest. LOOP owns and operates the only U.S. deepwater oil port.

• TAAE, in which we have a 43 percent noncontrolling interest, TACE, in which we have a 60 percent noncontrolling interest and TAME, in which we have a 67 percent direct and indirect noncontrolling interest. These companies each own and operate an ethanol production facility.

• Other equity method investees.

We believe that transactions with related parties were conducted on terms comparable to those with unaffiliated parties.

Sales to related parties, which are included in sales and other operating revenues (including consumer excise taxes) on the consolidated statements of income, were $2 million for both the three months ended June 30, 2015 and 2014 and $3 million and $4 million for the six months ended June 30, 2015 and 2014, respectively.

10

Purchases from related parties were as follows:

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015		2014			2015		2014
Centennial	$	—	$	(2	)	$	—	$	7
Explorer	7		9			14		22
LOCAP	6		5			11		10
LOOP	13		12			26		65
TAAE	15		26			28		42
TACE	15		30			31		57
TAME	23		48			43		82
Other equity method investees	3		2			5		4
Total	$	82	$	130		$	158	$	289

Related party purchases from Centennial consist primarily of refinery feedstocks and refined product transportation costs. Related party purchases from Explorer consist primarily of refined product transportation costs. Related party purchases from LOCAP, LOOP and other equity method investees consist primarily of crude oil transportation costs and crude oil purchases. Related party purchases from TAAE, TACE and TAME consist of ethanol purchases.

Receivables from related parties, which are included in receivables, less allowance for doubtful accounts on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Centennial	$	1	$	2
Explorer	—		2
TAME	—		3
Total	$	1	$	7

Payables to related parties, which are included in accounts payable on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Explorer	$	4	$	3
LOCAP	2		2
LOOP	5		4
TAAE	1		2
TACE	2		2
TAME	3		5
Total	$	17	$	18

7. Income per Common Share

We compute basic earnings per share by dividing net income attributable to MPC by the weighted average number of shares of common stock outstanding. The average number of shares of common stock and per share amounts have been retroactively restated to reflect the two-for-one stock split completed in June 2015. Diluted income per share assumes exercise of certain stock-based compensation awards, provided the effect is not anti-dilutive.

MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities. Due to the presence of participating securities, we have calculated our earnings per share using the two-class method.

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	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Basic earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – basic	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Basic earnings per share	$	1.52	$	1.49	$	3.16	$	1.81
Diluted earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – diluted	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Effect of dilutive securities	3		4		4		4
Weighted average common shares, including dilutive effect	544		578		547		584
Diluted earnings per share	$	1.51	$	1.48	$	3.14	$	1.80

The following table summarizes the shares that were anti-dilutive, and therefore, were excluded from the diluted share calculation.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions)	2015	2014	2015	2014
Shares issued under stock-based compensation plans	1	1	1	1

8. Equity

On April 29, 2015, our board of directors approved a two-for-one stock split in the form of a stock dividend, which was distributed on June 10, 2015 to shareholders of record at the close of business on May 20, 2015. The total number of authorized shares of common stock and common stock par value per share remain unchanged. All historical share and per share data included in this report have been retroactively restated on a post-split basis.

Since January 1, 2012, we have repurchased a total of $6.89 billion of our common stock, leaving $1.11 billion available for repurchases as of June 30, 2015. We have acquired 191 million shares at an average cost per share of $36.12 under these authorizations. On July 29, 2015, our board of directors approved an additional $2.0 billion share repurchase authorization expiring in July 2017, bringing the total share repurchase authorizations to $10.0 billion.

We may utilize various methods to effect the repurchases, which could include open market repurchases, negotiated block transactions, accelerated share repurchases or open market solicitations for shares, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be discontinued at any time.

Total share repurchases were as follows for the three and six months ended June 30, 2015 and 2014:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Number of shares repurchased	8		10		12		26
Cash paid for shares repurchased	$	408	$	459	$	617	$	1,148
Effective average cost per delivered share	$	50.97	$	44.07	$	49.75	$	43.91

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At June 30, 2015, we had agreements to acquire 173,532 common shares for $9 million, which were settled in early July 2015.

9. Segment Information

We have three reportable segments: Refining & Marketing; Speedway; and Pipeline Transportation. Each of these segments is organized and managed based upon the nature of the products and services it offers.

• Refining & Marketing – refines crude oil and other feedstocks at our refineries in the Gulf Coast and Midwest regions of the United States, purchases ethanol and refined products for resale and distributes refined products through various means, including barges, terminals and trucks that we own or operate. We sell refined products to wholesale marketing customers domestically and internationally, to buyers on the spot market, to our Speedway segment and to independent entrepreneurs who operate Marathon^® retail outlets.

• Speedway – sells transportation fuels and convenience merchandise in retail markets in the Midwest, East Coast and Southeast regions of the United States.

• Pipeline Transportation – transports crude oil and other feedstocks to our refineries and other locations, delivers refined products to wholesale and retail market areas. This segment includes the aggregated operations of MPLX.

On September 30, 2014, we acquired Hess’ Retail Operations and Related Assets, substantially all of which are part of the Speedway segment. Segment information for the periods prior to the acquisition do not include amounts for these operations. See Note 4.

Segment income represents income from operations attributable to the reportable segments. Corporate administrative expenses and costs related to certain non-operating assets are not allocated to the reportable segments. In addition, certain items that affect comparability (as determined by the chief operating decision maker) are not allocated to the reportable segments.

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2015
Revenues:
Customer	$	15,192	$	5,329	$	16	$	20,537
Intersegment(a)	3,425		2		148		3,575
Segment revenues	$	18,617	$	5,331	$	164	$	24,112
Segment income from operations(b)	$	1,206	$	127	$	79	$	1,412
Income from equity method investments	8		—		12		20
Depreciation and amortization(c)	268		62		19		349
Capital expenditures and investments(d)	207		100		157		464

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2014
Revenues:
Customer	$	22,917	$	3,908	$	19	$	26,844
Intersegment(a)	2,590		1		131		2,722
Segment revenues	$	25,507	$	3,909	$	150	$	29,566
Segment income from operations(b)	$	1,260	$	94	$	81	$	1,435
Income from equity method investments	35		—		22		57
Depreciation and amortization(c)	264		29		19		312
Capital expenditures and investments(d)	235		44		64		343

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(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2015
Revenues:
Customer	$	27,836	$	9,860	$	32	$	37,728
Intersegment(a)	6,158		2		282		6,442
Segment revenues	$	33,994	$	9,862	$	314	$	44,170
Segment income from operations(b)	$	2,522	$	295	$	146	$	2,963
Income from equity method investments	14		—		21		35
Depreciation and amortization(c)	535		125		39		699
Capital expenditures and investments(d)	436		145		238		819

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2014
Revenues:
Customer	$	42,727	$	7,366	$	36	$	50,129
Intersegment(a)	4,823		2		260		5,085
Segment revenues	$	47,550	$	7,368	$	296	$	55,214
Segment income from operations(b)	$	1,622	$	152	$	153	$	1,927
Income from equity method investments	59		—		33		92
Depreciation and amortization(c)	525		57		38		620
Capital expenditures and investments(d)	413		76		194		683

^(a)  Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below.

^(d)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

The following reconciles segment income from operations to income before income taxes as reported in the consolidated statements of income:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Segment income from operations	$	1,412		$	1,435		$	2,963		$	1,927
Items not allocated to segments:
Corporate and other unallocated items(a)(b)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses(c)	(1		)	(5		)	(2		)	(69		)
Net interest and other financial income (costs)	(64		)	(48		)	(145		)	(94		)
Income before income taxes	$	1,271		$	1,321		$	2,660		$	1,636

^(a)  Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  See Note 19.

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The following reconciles segment capital expenditures and investments to total capital expenditures:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions)	2015		2014		2015		2014
Segment capital expenditures and investments	$	464	$	343	$	819	$	683
Less: Investments in equity method investees	107		41		149		164
Plus: Items not allocated to segments:
Capital expenditures not allocated to segments	41		13		62		38
Capitalized interest	8		7		16		13
Total capital expenditures(a)	$	406	$	322	$	748	$	570

^(a)  Capital expenditures include changes in capital accruals. See Note 17 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

10. Other Items

Net interest and other financial income (costs) was:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Interest income	$	2		$	1		$	3		$	3
Interest expense	(69		)	(49		)	(149		)	(98		)
Interest capitalized	8			7			16			13
Other financial costs	(5		)	(7		)	(15		)	(12		)
Net interest and other financial income (costs)	$	(64	)	$	(48	)	$	(145	)	$	(94	)

11. Income Taxes

The combined federal, state and foreign income tax rate was 34 percent and 35 percent for the three months ended June 30, 2015 and 2014, respectively and 35 percent for both the six months ended June 30, 2015 and 2014. The effective tax rate for the three and six months ended June 30, 2015 and 2014 is equivalent to or slightly less than the U.S. statutory rate of 35 percent primarily due to certain permanent benefit differences, including the domestic manufacturing deduction, partially offset by state and local tax expense.

We are continuously undergoing examination of our income tax returns, which have been completed for our U.S. federal and state income tax returns through the 2009 and 2003 tax years, respectively. We had $12 million of unrecognized tax benefits as of June 30, 2015. Pursuant to our tax sharing agreement with Marathon Oil, the unrecognized tax benefits related to pre-spinoff operations for which Marathon Oil was the taxpayer remain the responsibility of Marathon Oil and we have indemnified Marathon Oil accordingly. See Note 21 for indemnification information.

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12. Inventories

(In millions)	June 30, 2015		December 31, 2014
Crude oil and refinery feedstocks	$	2,147	$	2,219
Refined products	2,880		2,955
Materials and supplies	338		302
Merchandise	175		166
Total (at cost)	$	5,540	$	5,642

Inventories are carried at the lower of cost or market value. The cost of inventories of crude oil and refinery feedstocks, refined products and merchandise is determined primarily under the last-in, first-out (“LIFO”) method. During the six months ended June 30, 2015, we recorded LIFO liquidations caused by permanently decreased levels in refined products inventory volumes. Cost of revenues increased and income from operations decreased by approximately $30 million for the six months ended June 30, 2015 as a result of the LIFO liquidations. There were no liquidations of LIFO inventories for the six months ended June 30, 2014.

13. Property, Plant and Equipment

(In millions)	June 30, 2015		December 31, 2014
Refining & Marketing	$	18,434	$	18,001
Speedway	4,762		4,639
Pipeline Transportation	2,132		2,044
Corporate and Other	679		618
Total	26,007		25,302
Less accumulated depreciation	9,724		9,041
Property, plant and equipment, net	$	16,283	$	16,261

Included in construction in progress at June 30, 2015 is $136 million of costs associated with a residual fuel hydrocracker project at our Garyville refinery, which is intended to increase margins by upgrading residual fuel to ultra-low sulfur diesel and gas oil. We are deferring a final investment decision on this project as we further evaluate the implications of current market conditions on the project. If a decision is made to not pursue this project, there could be a future impairment of the costs incurred for the project.

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14. Fair Value Measurements

Fair Values—Recurring

The following tables present assets and liabilities accounted for at fair value on a recurring basis as of June 30, 2015 and December 31, 2014 by fair value hierarchy level. We have elected to offset the fair value amounts recognized for multiple derivative contracts executed with the same counterparty, including any related cash collateral as shown below; however, fair value amounts by hierarchy level are presented on a gross basis in the following tables.

	June 30, 2015
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	61	$	—	$	—	$	(43	)	$	18	$	20
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	63	$	—	$	—	$	(43	)	$	20	$	20
Commodity derivative instruments, liabilities	$	55	$	—	$	—	$	(55	)	$	—	$	—
Contingent consideration, liability(c)	—		—		307		N/A			307		—
Total liabilities at fair value	$	55	$	—	$	307	$	(55	)	$	307	$	—

	December 31, 2014
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	317	$	—	$	—	$	(258	)	$	59	$	—
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	319	$	—	$	—	$	(258	)	$	61	$	—
Commodity derivative instruments, liabilities	$	180	$	—	$	—	$	(180	)	$	—	$	—
Contingent consideration, liability(c)	—		—		478		N/A			478		—
Total liabilities at fair value	$	180	$	—	$	478	$	(180	)	$	478	$	—

^(a)  Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of June 30, 2015, cash collateral of $12 million was netted with the mark-to-market derivative liabilities. As of December 31, 2014, $78 million was netted with mark-to-market derivative assets.

^(b)  We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.

^(c)  Includes $190 million and $174 million classified as current at June 30, 2015 and December 31, 2014, respectively.

Commodity derivatives in Level 1 are exchange-traded contracts for crude oil and refined products measured at fair value with a market approach using the close-of-day settlement prices for the market. Commodity derivatives are covered under master netting agreements with an unconditional right to offset. Collateral deposits in futures commission merchant accounts covered by master netting agreements related to Level 1 commodity derivatives are classified as Level 1 in the fair value hierarchy.

The contingent consideration represents the fair value as of June 30, 2015 and December 31, 2014 of the remaining amount we expect to pay to BP related to the earnout provision associated with our 2013 acquisition of BP’s refinery in Texas City, Texas and related logistics and marketing assets. We refer to these assets as the “Galveston Bay Refinery and Related Assets.” The fair value of the remaining contingent consideration was estimated using an income approach and is therefore a Level 3 liability. The amount of cash to be paid under the arrangement is based on both a market-based crack spread and refinery throughput volumes for the months during which the earnout applies, as well as established thresholds that cap the annual and total payment. The earnout payment cannot exceed $200 million per year for the first three years of the arrangement or $250 million per year for the last three years of the arrangement, with the total cumulative payment capped at $700 million over the six-year period commencing in 2014. Any excess or shortfall from the annual cap for a current year’s earnout calculation will not affect subsequent years’ calculations. The fair value calculation used significant unobservable inputs, including: (1) an estimate of monthly refinery throughput volumes; (2) a range of internal and external monthly crack spread forecasts from approximately $8 to $20 per barrel; and (3) a range of risk-adjusted discount rates from five percent to 10 percent. An increase or decrease in crack spread forecasts or refinery throughput volume expectations may result in a corresponding increase or decrease in the fair value. Increases to the fair value as a result of increasing forecasts for both of these unobservable inputs,

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however, are limited as the earnout payment is subject to annual caps. An increase or decrease in the discount rate may result in a decrease or increase to the fair value, respectively. The fair value of the contingent consideration is reassessed each quarter, with changes in fair value recorded in cost of revenues.

In June 2015, we paid BP $189 million for the second year’s contingent earnout. On the consolidated statements of cash flows for the six months ended June 30, 2015, $175 million of the contingent earnout payment is included as a financing activity with the remainder included as an operating activity. In the third quarter of 2014, we paid BP $180 million for the first year’s contingent earnout.

The following is a reconciliation of the beginning and ending balances recorded for liabilities classified as Level 3 in the fair value hierarchy.

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015			2014		2015			2014
Beginning balance	$	490		$	639	$	478		$	625
Contingent consideration payment	(189		)	—		(189		)	—
Unrealized and realized losses included in net income	6			8		18			22
Ending balance	$	307		$	647	$	307		$	647

We did not hold any Level 3 derivative instruments during the three and six months ended June 30, 2015 and 2014. See Note 15 for the income statement impacts of our derivative instruments.

Fair Values - Nonrecurring

The following table shows the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition.

	Six Months Ended June 30,
	2015				2014
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Other noncurrent assets	$	—	$	—	$	—	$	11

Based on the financial and operational status of a company in which we have an interest, we fully impaired our $11 million investment in that company during the second quarter of 2014. Our investment in this company was accounted for using the cost method and was included in our Refining & Marketing segment. The impairment is included in other income on the consolidated statements of income. The fair value of our investment in this cost company was measured using an income approach. This measurement is classified as Level 3.

Fair Values – Reported

The following table summarizes financial instruments on the basis of their nature, characteristics and risk at June 30, 2015 and December 31, 2014, excluding the derivative financial instruments and contingent consideration reported above.

	June 30, 2015				December 31, 2014
(In millions)	Fair Value		Carrying Value		Fair Value		Carrying Value
Financial assets:
Investments	$	34	$	2	$	26	$	2
Other	32		31		32		32
Total financial assets	$	66	$	33	$	58	$	34
Financial liabilities:
Long-term debt(a)	$	6,537	$	6,376	$	6,571	$	6,265
Deferred credits and other liabilities	19		19		17		17
Total financial liabilities	$	6,556	$	6,395	$	6,588	$	6,282

^(a)  Excludes capital leases and debt issuance costs, however, includes amount classified as short-term debt.

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Our current assets and liabilities include financial instruments, the most significant of which are trade accounts receivable and payables. We believe the carrying values of our current assets and liabilities approximate fair value. Our fair value assessment incorporates a variety of considerations, including (1) the short-term duration of the instruments, (2) our investment-grade credit rating and (3) our historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk.

Fair values of our financial assets included in investments and other financial assets and of our financial liabilities included in deferred credits and other liabilities are measured primarily using an income approach and most inputs are internally generated, which results in a Level 3 classification. Estimated future cash flows are discounted using a rate deemed appropriate to obtain the fair value. Other financial assets primarily consist of environmental remediation receivables. Deferred credits and other liabilities primarily consist of insurance liabilities and environmental remediation liabilities.

Fair value of fixed-rate long-term debt is measured using a market approach, based upon the average of quotes from major financial institutions and a third-party service for our debt. Because these quotes cannot be independently verified to the market, they are considered Level 3 inputs. Fair value of variable-rate long-term debt approximates the carrying value.

15. Derivatives

For further information regarding the fair value measurement of derivative instruments, including any effect of master netting agreements or collateral, see Note 14. We do not designate any of our commodity derivative instruments as hedges for accounting purposes.

Derivatives that are not designated as accounting hedges may include commodity derivatives used to hedge price risk on (1) inventories, (2) fixed price sales of refined products, (3) the acquisition of foreign-sourced crude oil and (4) the acquisition of ethanol for blending with refined products.

The following table presents the gross fair values of derivative instruments, excluding cash collateral, and where they appear on the consolidated balance sheets as of June 30, 2015 and December 31, 2014:

	June 30, 2015
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	61	$	55	Other current assets
	December 31, 2014
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	317	$	180	Other current assets

The table below summarizes open commodity derivative contracts as of June 30, 2015.

	Position	Total Barrels (In thousands)
Crude oil(a)
Exchange-traded	Long	12,403
Exchange-traded	Short	(24,938	)
Refined Products(b)
Exchange-traded	Long	4,004
Exchange-traded	Short	(2,439	)

^(a)  96.5 percent of these contracts expire in the third quarter of 2015.

^(b)  100 percent of these contracts expire in the third quarter of 2015.

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The following table summarizes the effect of all commodity derivative instruments in our consolidated statements of income:

	Gain (Loss)						Gain (Loss)
(In millions)	Three Months Ended June 30,						Six Months Ended June 30,
Income Statement Location	2015			2014			2015			2014
Sales and other operating revenues	$	(3	)	$	(2	)	$	11		$	8
Cost of revenues	(70		)	(114		)	(25		)	(175		)
Total	$	(73	)	$	(116	)	$	(14	)	$	(167	)

16. Debt

Our outstanding borrowings at June 30, 2015 and December 31, 2014 consisted of the following:

(In millions)	June 30, 2015			December 31, 2014
Marathon Petroleum Corporation:
3.500% senior notes due March 1, 2016	$	750		$	750
Revolving credit agreement due 2017	—			—
Term loan agreement due 2019	700			700
5.125% senior notes due March 1, 2021	1,000			1,000
3.625% senior notes due September 15, 2024	750			750
6.500% senior notes due March 1, 2041	1,250			1,250
4.750% senior notes due September 15, 2044	800			800
5.000% senior notes due September 15, 2054	400			400
Consolidated subsidiaries:
Capital lease obligations due 2015-2028	360			372
MPLX bank revolving credit facility due 2019	—			385
MPLX term loan facility due 2019	250			250
MPLX 4.000% senior notes due February 15, 2025	500			—
Trade receivables securitization facility due 2016	—			—
Total	6,760			6,657
Unamortized debt issuance costs(a)	(38		)	(35		)
Unamortized discount	(27		)	(26		)
Fair value adjustments(b)	3			6
Amounts due within one year	(780		)	(27		)
Total long-term debt due after one year	$	5,918		$	6,575

^(a)  We adopted the updated FASB debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented. We reclassified unamortized debt issuance costs related to term debt from other noncurrent assets to long-term debt.

^(b)  The $20 million gain on the termination of our interest rate swap agreements in 2012 is being amortized over the remaining life of the 3.50 percent senior notes.

MPLX Senior Notes – On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of MPLX Senior Notes, the net proceeds of which were approximately $495 million, after deducting underwriting discounts. The net proceeds of this offering were used to repay the amounts outstanding under the MPLX revolving credit agreement (the “MPLX Credit Agreement”), as well as for general partnership purposes. Interest is payable semi-annually in arrears on February 15 and August 15 of each year, commencing on August 15, 2015.

There were no borrowings or letters of credit outstanding under the MPC revolving credit facility or the trade receivables securitization facility at June 30, 2015. As of June 30, 2015, eligible trade receivables supported available borrowings of $1.2 billion under the $1.3 billion trade receivables facility. During the six months ended June 30, 2015, MPLX borrowed $30 million under the MPLX Credit Agreement at an average interest rate of 1.5 percent, per annum, and repaid $415 million of these borrowings. At June 30, 2015, MPLX had no borrowings and no letters of credit outstanding under the MPLX Credit Agreement, resulting in total unused loan availability of $1 billion, or 100 percent of the borrowing capacity.

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17. Supplemental Cash Flow Information

	Six Months Ended   June 30,
(In millions)	2015		2014
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$	130	$	82
Net income taxes paid to taxing authorities	1,039		299
Non-cash investing and financing activities:
Property, plant and equipment sold	4		4
Property, plant and equipment acquired	4		4

The consolidated statements of cash flows exclude changes to the consolidated balance sheets that did not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditures:

	Six Months Ended   June 30,
(In millions)	2015			2014
Additions to property, plant and equipment per consolidated statements of cash flows	$	764		$	569
Non-cash additions to property, plant and equipment	4			4
Asset retirement expenditures	—			1
Decrease in capital accruals	(20		)	(31		)
Total capital expenditures before acquisitions	$	748		$	543
Acquisitions	—			27
Total capital expenditures	$	748		$	570

18. Accumulated Other Comprehensive Loss

The following table shows the changes in accumulated other comprehensive loss by component. Amounts in parentheses indicate debits.

(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2013	$	(161	)	$	(50	)	$	4	$	3		$	(204	)
Other comprehensive income (loss) before reclassifications	(65		)	8			—		(1		)	(58		)
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			1			—		—			27
– settlement loss(a)	69			—			—		—			69
Tax effect	(28		)	1			—		—			(27		)
Other comprehensive income (loss)	(21		)	8			—		(1		)	(14		)
Balance as of June 30, 2014	$	(182	)	$	(42	)	$	4	$	2		$	(218	)

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(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2014	$	(217	)	$	(104	)	$	4	$	4		$	(313	)
Other comprehensive loss before reclassifications	(12		)	14			—		(2		)	—
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			4			—		—			30
– settlement loss(a)	2			—			—		—			2
Tax effect	(2		)	(1		)	—		—			(3		)
Other comprehensive income (loss)	(9		)	15			—		(2		)	4
Balance as of June 30, 2015	$	(226	)	$	(89	)	$	4	$	2		$	(309	)

^(a)  These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 19.

19. Defined Benefit Pension and Other Postretirement Plans

The following summarizes the components of net periodic benefit costs:

	Three Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	28		$	20		$	7		$	6
Interest cost	18			18			8			9
Expected return on plan assets	(24		)	(26		)	—			—
Amortization – prior service credit	(11		)	(11		)	(1		)	(1		)
– actuarial loss	13			13			1			—
– settlement loss	1			5			—			—
Net periodic benefit cost	$	25		$	19		$	15		$	14

	Six Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	51		$	43		$	15		$	13
Interest cost	36			38			16			17
Expected return on plan assets	(50		)	(54		)	—			—
Amortization – prior service credit	(23		)	(23		)	(2		)	(2		)
– actuarial loss	26			26			4			1
– settlement loss	2			69			—			—
Net periodic benefit cost	$	42		$	99		$	33		$	29

During the six months ended June 30, 2015, we made no contributions to our funded pension plans. We have no required funding for 2015, but may make voluntary contributions at our discretion. Current benefit payments related to unfunded pension and other postretirement benefit plans were $6 million and $12 million, respectively, during the six months ended June 30, 2015.

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During the six months ended June 30, 2015 and 2014, we determined that lump sum payments to employees retiring in the respective years will exceed the plans’ total service and interest costs for the year. Settlement losses are required to be recorded when lump sum payments exceed total service and interest costs. As a result, during the six months ended June 30, 2015 and 2014, we recorded pension settlement expenses of $2 million and $69 million related to our lump sum payments made during the first six months of 2015 and 2014, respectively.

20. Stock-Based Compensation Plans

Stock Option Awards

The following table presents a summary of our stock option award activity for the six months ended June 30, 2015:

	Number of Shares		Weighted Average Exercise Price
Outstanding at December 31, 2014	9,502,876		$	22.74
Granted	1,094,676		50.89
Exercised	(1,492,710	)	17.49
Forfeited, canceled or expired	(48,766	)	39.84
Outstanding at June 30, 2015	9,056,076		26.91

The grant date fair value of stock option awards granted during the six months ended June 30, 2015 was $13.45 per share. The fair value of stock options granted to our employees is estimated on the date of the grant using the Black Scholes option-pricing model, which employs various assumptions.

Restricted Stock Awards

The following table presents a summary of restricted stock award activity for the six months ended June 30, 2015:

	Shares of Restricted Stock (“RS”)				Restricted Stock Units (“RSU”)
	Number of Shares		Weighted Average Grant Date Fair Value		Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	1,030,146		$	38.62	822,186		$	18.65
Granted	505,698		50.86		23,831		48.65
RS’s Vested/RSU’s Issued	(516,406	)	34.12		(944	)	34.26
Forfeited	(34,396	)	39.22		(850	)	44.77
Outstanding at June 30, 2015	985,042		47.24		844,223		19.45

Performance Unit Awards

The following table presents a summary of the activity for performance unit awards to be settled in shares for the six months ended June 30, 2015:

	Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	5,791,825		$	0.88
Granted	2,389,450		0.95
Settled	(2,035,833	)	0.85
Outstanding at June 30, 2015	6,145,442		0.92

The performance unit awards granted during the six months ended June 30, 2015 have a grant date fair value of $0.95 per unit, as calculated using a Monte Carlo valuation model.

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MPLX Awards

During the six months ended June 30, 2015, MPLX granted equity-based compensation awards under the MPLX LP 2012 Incentive Compensation Plan. The compensation expense for these awards is not material to our consolidated financial statements.

21. Commitments and Contingencies

We are the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which we have not recorded an accrued liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings and discovery. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material.

Environmental matters—We are subject to federal, state, local and foreign laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites and certain other locations including presently or formerly owned or operated retail marketing sites. Penalties may be imposed for noncompliance.

At June 30, 2015 and December 31, 2014, accrued liabilities for remediation totaled $172 million and $185 million, respectively. It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties if any that may be imposed. Receivables for recoverable costs from certain states, under programs to assist companies in clean-up efforts related to underground storage tanks at presently or formerly owned or operated retail marketing sites, was $66 million and $67 million at June 30, 2015 and December 31, 2014, respectively.

We are involved in a number of environmental enforcement matters arising in the ordinary course of business. While the outcome and impact on us cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on our consolidated results of operations, financial position or cash flows.

Lawsuits—In May 2015, the Kentucky attorney general filed a lawsuit against our wholly owned subsidiary, Marathon Petroleum Company LP (“MPCLP”) in the United States District Court for the Western District of Kentucky asserting claims under federal and state antitrust statutes, the Kentucky Consumer Protection Act, and state common law. The complaint, as amended in July 2015, alleges that MPCLP used deed restrictions, supply agreements with customers and exchange agreements with competitors to unreasonably restrain trade in areas within Kentucky and seeks declaratory relief, unspecified damages, civil penalties, restitution and disgorgement of profits. At this early stage, the ultimate outcome of this litigation remains uncertain, and neither the likelihood of an unfavorable outcome nor the ultimate liability, if any, can be determined, and we are unable to estimate a reasonably possible loss (or range of loss) for this matter. We intend to vigorously defend ourselves in this matter.

In May 2007, the Kentucky attorney general filed a lawsuit against us and Marathon Oil in state court in Franklin County, Kentucky for alleged violations of Kentucky’s emergency pricing and consumer protection laws following Hurricanes Katrina and Rita in 2005. The lawsuit alleges that we overcharged customers by $89 millionduring September and October 2005. The complaint seeks disgorgement of these sums, as well as penalties, under Kentucky’s emergency pricing and consumer protection laws. We are vigorously defending this litigation. We believe that this is the first lawsuit for damages and injunctive relief under the Kentucky emergency pricing laws to progress this far and it contains many novel issues. In May 2011, the Kentucky attorney general amended his complaint to include a request for immediate injunctive relief as well as unspecified damages and penalties related to our wholesale gasoline pricing in April and May 2011 under statewide price controls that were activated by the Kentucky governor on April 26, 2011 and which have since expired. The court denied the attorney general’s request for immediate injunctive relief, and the remainder of the 2011 claims likely will be resolved along with those dating from 2005. If the lawsuit is resolved unfavorably in its entirety, it could materially impact our consolidated results of operations, financial position or cash flows. However, management does not believe the ultimate resolution of this litigation will have a material adverse effect.

We are also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to us cannot be predicted with certainty, we believe that the resolution of these other lawsuits and proceedings will not have a material adverse effect on our consolidated financial position, results of operations or cash flows.

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Guarantees—We have provided certain guarantees, direct and indirect, of the indebtedness of other companies. Under the terms of most of these guarantee arrangements, we would be required to perform should the guaranteed party fail to fulfill its obligations under the specified arrangements. In addition to these financial guarantees, we also have various performance guarantees related to specific agreements.

Guarantees related to indebtedness of equity method investees—We hold interests in an offshore oil port, LOOP, and a crude oil pipeline system, LOCAP. Both LOOP and LOCAP have secured various project financings with throughput and deficiency agreements. Under the agreements, we are required to advance funds if the investees are unable to service their debt. Any such advances are considered prepayments of future transportation charges. The duration of the agreements vary but tend to follow the terms of the underlying debt, which extend through 2037. Our maximum potential undiscounted payments under these agreements for the debt principal totaled $172 million as of June 30, 2015.

We hold an interest in a refined products pipeline through our investment in Centennial, and have guaranteed our portion of the payment of Centennial’s principal, interest and prepayment costs, if applicable, under a Master Shelf Agreement, which is scheduled to expire in 2024. The guarantee arose in order for Centennial to obtain adequate financing. Our maximum potential undiscounted payments under this agreement for debt principal totaled $36 million as of June 30, 2015.

Marathon Oil indemnifications—In conjunction with our spinoff from Marathon Oil, we have entered into arrangements with Marathon Oil providing indemnities and guarantees with recorded values of $2 million as of June 30, 2015, which consist of unrecognized tax benefits related to MPC, its consolidated subsidiaries and the refining, marketing and transportation business operations prior to our spinoff which are not already reflected in the unrecognized tax benefits described in Note 11, and other contingent liabilities Marathon Oil may incur related to taxes. Furthermore, the separation and distribution agreement and other agreements with Marathon Oil to effect our spinoff provide for cross-indemnities between Marathon Oil and us. In general, Marathon Oil is required to indemnify us for any liabilities relating to Marathon Oil’s historical oil and gas exploration and production operations, oil sands mining operations and integrated gas operations, and we are required to indemnify Marathon Oil for any liabilities relating to Marathon Oil’s historical refining, marketing and transportation operations. The terms of these indemnifications are indefinite and the amounts are not capped.

Other guarantees—We have entered into other guarantees with maximum potential undiscounted payments totaling $82 million as of June 30, 2015, which primarily consist of a commitment to contribute cash to an equity method investee for certain catastrophic events, up to $50 million per event, in lieu of procuring insurance coverage and leases of assets containing general lease indemnities and guaranteed residual values.

General guarantees associated with dispositions – Over the years, we have sold various assets in the normal course of our business. Certain of the related agreements contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require us to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. We are typically not able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the underlying triggering event has little or no past experience upon which a reasonable prediction of the outcome can be based.

Contractual commitments—At June 30, 2015, our contractual commitments to acquire property, plant and equipment and advance funds to equity method investees totaled $1.7 billion, which includes $331 million of contingent consideration associated with the acquisition of the Galveston Bay Refinery and Related Assets, $659 million for contributions to North Dakota Pipeline Company LLC and $116 million for contributions to Illinois Extension Pipeline. See Note 4 for additional information on our investments in the SAX project. See Note 14 for additional information on the contingent consideration.

22. Subsequent Events

On July 11, 2015, MPLX and MarkWest Energy Partners, L.P. (“MWE”) entered into a definitive merger agreement whereby MWE would become a wholly owned subsidiary of MPLX. Under the terms of the agreement, each common unit of MWE issued and outstanding will be converted into the right to receive 1.09 common units of MPLX representing limited partner interests in MPLX, plus a one-time cash payment to MWE unitholders. As of the close of trading on Friday, July 10, 2015, the implied total enterprise value for MWE was approximately $20 billion, including the assumption of debt of approximately $4.2 billion. MPC would contribute $675 million of cash to MPLX to fund the one-time cash payment. The transaction between MPLX and MWE, which is subject to approval by MWE unitholders and to customary closing conditions and regulatory approvals, is expected to close in the fourth quarter of 2015. Following completion of the transaction, we expect to continue to consolidate MPLX’s financial results.

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The combination of MarkWest and MPLX defers the need for the recently proposed sale of MPC's marine business to MPLX in 2015. As a result, that transaction has been indefinitely postponed.

In July 2015, a purported class action lawsuit asserting claims challenging the proposed merger of MPLX and MWE was filed in the Court of Chancery of the State of Delaware by a purported unitholder of MWE. The lawsuit alleges that the individual members of the board of directors of MarkWest Energy GP, L.L.C. the general partner of MWE, breached their fiduciary and/or contractual duties to the unitholders of MWE and that MPLX, MPC and Sapphire Holdco LLC, a subsidiary of MPLX, aided and abetted those breaches. The complaint seeks to enjoin the proposed merger or, if the merger is consummated, to rescind the transaction or recover rescission damages. The lawsuit also seeks an accounting and recovery of attorneys’ fees, experts’ fees, and other litigation costs. We believe the allegations in the complaint are without merit.

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Item 2: Management’s Discussion and Analysis of Financial Condition and Results of Operations

Management’s Discussion and Analysis of Financial Condition and Results of Operations should be read in conjunction with the unaudited financial statements and accompanying footnotes included under Item 1. Financial Statements and in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2014.

Management’s Discussion and Analysis of Financial Condition and Results of Operations includes various forward-looking statements concerning trends or events potentially affecting our business. You can identify our forward-looking statements by words such as “anticipate,” “believe,” “estimate,” “objective,” “expect,” “forecast,” “goal,” “intend,” “plan,” “predict,” “project,” “potential,” “seek,” “target,” “could,” “may,” “should,” “would,” “will” or other similar expressions that convey the uncertainty of future events or outcomes. In accordance with “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, these statements are accompanied by cautionary language identifying important factors, though not necessarily all such factors, which could cause future outcomes to differ materially from those set forth in forward-looking statements. For additional risk factors affecting our business, see Item 1A. Risk Factors in our Annual Report on Form 10-K for the year ended December 31, 2014.

Corporate Overview

We are an independent petroleum refining and marketing, retail marketing and pipeline transportation company. We currently own and operate seven refineries, all located in the United States, with an aggregate crude oil refining capacity of approximately 1.7 million barrels per calendar day. Our refineries supply refined products to resellers and consumers within our market areas, including the Midwest, Gulf Coast, East Coast and Southeast regions of the United States. We distribute refined products to our customers through one of the largest private domestic fleets of inland petroleum product barges, one of the largest terminal operations in the United States, and a combination of MPC-owned and third-party-owned trucking and rail assets. We are one of the largest wholesale suppliers of gasoline and distillates to resellers within our market area.

We have two strong retail brands: Speedway^® and Marathon^®. We believe that Speedway LLC, a wholly-owned subsidiary, operates the second largest chain of company-owned and operated retail gasoline and convenience stores in the United States, with approximately 2,760 convenience stores in 22 states throughout the Midwest, East Coast and Southeast. The Marathon brand is an established motor fuel brand in the Midwest and Southeast regions of the United States, and is available through approximately 5,500 retail outlets operated by independent entrepreneurs in 19 states.

We currently own, lease or have ownership interests in approximately 8,300 miles of crude oil and refined product pipelines to deliver crude oil to our refineries and other locations and refined products to wholesale and retail market areas. We are one of the largest petroleum pipeline companies in the United States on the basis of total volumes delivered.

Our operations consist of three reportable operating segments: Refining & Marketing; Speedway; and Pipeline Transportation. Each of these segments is organized and managed based upon the nature of the products and services it offers.

• Refining & Marketing—refines crude oil and other feedstocks at our seven refineries in the Gulf Coast and Midwest regions of the United States, purchases refined products and ethanol for resale and distributes refined products through various means, including barges, terminals and trucks that we own or operate. We sell refined products to wholesale marketing customers domestically and internationally, buyers on the spot market, our Speedway business segment and to independent entrepreneurs who operate Marathon^® retail outlets.

• Speedway—sells transportation fuels and convenience merchandise in the retail market in the Midwest, East Coast and Southeast regions of the United States.

• Pipeline Transportation—transports crude oil and other feedstocks to our refineries and other locations, delivers refined products to wholesale and retail market areas and includes the aggregated operations of MPLX.

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Executive Summary

Results

Select results for the three and six months ended June 30, 2015 and 2014 are reflected in the following table.

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Income from Operations by segment
Refining & Marketing	$	1,206	$	1,260	$	2,522	$	1,622
Speedway	127		94		295		152
Pipeline Transportation	79		81		146		153
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Net income attributable to MPC per diluted share	$	1.51	$	1.48	$	3.14	$	1.80

Net income attributable to MPC was $826 million, or $1.51 per diluted share, in the second quarter and $1.72 billion, or $3.14 per diluted share, in the first six months of2015 compared to $855 million, or $1.48 per diluted share, and $1.05 billion, or $1.80 per diluted share, for the same periods of 2014.

Refining & Marketing segment income from operations decreased $54 million in the second quarter and increased $900 millionin the first six months of2015compared to the same periods of2014. The decrease in the second quarter was primarily due to a $1.18 per barrel decrease in gross margin, resulting from less favorable product price realizations compared to the spot market reference prices and less favorable crude oil acquisition costs relative to benchmark Light Louisiana Sweet crude oil. Results were also affected by a charge of $46 million to recognize estimated costs for compliance with the recently proposed renewable fuel standards for 2014 and 2015, particularly those for bio-mass based diesel and advanced biofuels. These decreases were almost completely offset by the favorable effects that market structure had on crude oil acquisition prices and lower direct operating costs. The higher year to date results were primarily due to higher U.S. Gulf Coast (“USGC”) crack spreads and lower turnaround and other direct operating costs.

Speedway segment income from operations increased $33 million in the second quarter and $143 millionin the first six months of2015compared to the same periods of2014. The increases in both periods were primarily the result of higher merchandise and light product margins and the addition of newly acquired locations, partially offset by higher operating and administrative expenses.

Pipeline Transportation segment income from operations decreased $2 million in the second quarter and $7 millionin the first six months of2015compared to the same periods of2014, primarily due to lower equity affiliate income and increases in various operating expenses, partially offset by increases in pipeline transportation revenue reflecting higher crude and refined product throughput across the system.

MPLX LP

We own a 71.5 percent interest in MPLX, including the two percent general partner interest. Effective March 1, 2014, we sold MPLX a 13 percent interest in Pipe Line Holdings for $310 million. MPLX financed this transaction with $40 million of cash on-hand and $270 million of borrowings on its bank revolving credit agreement. On December 1, 2014, we sold and contributed interests in Pipe Line Holdings totaling 30.5 percent to MPLX for $600 million in cash and 2.9 million MPLX common units valued at $200 million. MPLX financed the sales portion of this transaction with $600 million of borrowings on its bank revolving credit facility. See Note 3 to the unaudited consolidated financial statements for additional information on MPLX.

The following table summarizes the cash distributions we received from MPLX during the first six months of 2015 and 2014.

	Six Months Ended   June 30,
(In millions)	2015		2014
Cash distributions received from MPLX:
General partner distributions, including incentive distribution rights	$	6	$	1
Limited partner distributions	45		35
Total	$	51	$	36

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The market value of the 19,980,619 MPLX common units and 36,951,515 MPLX subordinated units we owned at June 30, 2015 was $4.1 billion based on the June 30, 2015 closing unit price of $71.38. Over time, we believe there will be substantial value attributable to our general partnership interests.

On July 21, 2015, MPLX declared a quarterly cash distribution of $0.4400 per unit, totaling $42 million. This distribution will be paid on August 14, 2015. MPC’s portion of this cash distribution is approximately $31 million. As a result, upon payment of the second-quarter distribution, the financial tests required for conversion of all of the MPLX subordinated units, which are owned by a subsidiary of MPC, will have been met. Accordingly, the subordinated units will convert into common units on a one-for-one basis effective Aug. 17, 2015, the first business day following the payment of the second quarter distribution.

On July 11, 2015, MPLX and MarkWest Energy Partners, L.P. (“MWE”) entered into a definitive merger agreement whereby MWE would become a wholly owned subsidiary of MPLX. Under the terms of the agreement, each common unit of MWE issued and outstanding will be converted into the right to receive 1.09 common units of MPLX representing limited partner interests in MPLX, plus a one-time cash payment to MWE unitholders. As of the close of trading on Friday, July 10, 2015, the implied total enterprise value for MWE was approximately $20 billion, including the assumption of debt of approximately $4.2 billion. MPC would contribute $675 million of cash to MPLX to fund the one-time cash payment. The transaction between MPLX and MWE, which is subject to approval by MWE unitholders and to customary closing conditions and regulatory approvals, is expected to close in the fourth quarter of 2015. Following completion of the transaction, we expect to continue to consolidate MPLX’s financial results.

The combination of MWE and MPLX defers the need for the recently proposed sale of MPC's marine business to MPLX in 2015. As a result, that transaction has been indefinitely postponed.

On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of MPLX Senior Notes. See Note 16 to the unaudited consolidated financial statements for more information.

Acquisitions and Investments

On September 30, 2014, we acquired from Hess all of its retail locations, transport operations and shipper history on various pipelines, including approximately 40,000 barrels per day on Colonial Pipeline for $2.82 billion. We refer to these assets as “Hess’ Retail Operations and Related Assets” and substantially all of these assets are part of our Speedway segment. This acquisition significantly expands our Speedway presence from nine to 22 states throughout the East Coast and Southeast and is aligned with our strategy to grow higher-valued, stable cash flow businesses. This acquisition also enables us to further leverage our integrated refining and transportation operations, providing an outlet for an incremental 200 thousand barrels per day (“mbpd”) of assured sales from our refining system. The transaction was funded with a combination of debt and available cash. Our financial results and operating statistics for the periods prior to the acquisition do not include amounts for Hess’ Retail Operations and Related Assets. See Note 4 to the unaudited consolidated financial statements for additional information on this acquisition.

In July 2014, we exercised our option to acquire a 35 percent ownership interest in Enbridge Inc.’s SAX pipeline through our investment in Illinois Extension Pipeline. During the six months ended June 30, 2015, we made contributions of $94 million to Illinois Extension Pipeline to fund our portion of the construction costs for the SAX project. We have contributed $214 million since project inception. See Note 21 to the unaudited consolidated financial statements for information regarding our future contributions to the SAX pipeline project.

In March 2014, we acquired from Chevron Raven Ridge Pipe Line Company an additional seven percent interest in Explorer for $77 million, bringing our ownership interest to 25 percent. Due to this increase in our ownership percentage, we now account for our investment in Explorer using the equity method of accounting and report Explorer as a related party. Explorer owns approximately 1,900 miles of refined products pipeline from Lake Charles, Louisiana to Hammond, Indiana.

Share Repurchases and Dividends

Since January 1, 2012, we have repurchased a total of $6.89 billion of our common stock, leaving $1.11 billion available for repurchases as of June 30, 2015. On July 29, 2015, our board of directors approved an additional $2.0 billion share repurchase authorization expiring in July 2017, bringing the total share repurchase authorizations to $10.0 billion. See Note 8 to the unaudited consolidated financial statements.

On July 29, 2015, our board of directors approved a dividend of $0.32 per share on common stock, a 28 percent increase in its quarterly dividend over the first quarter of 2015, after adjusting to reflect the two-for-one stock split that occurred in the second quarter. The dividend is payable September 10, 2015, to shareholders of record as of the close of business on August 19, 2015.

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Liquidity

As of June 30, 2015, we had cash and cash equivalents of $1.88 billion, an unused $2.5 billion revolving credit agreement, and $1.2 billion of availability under our $1.3 billion trade receivables securitization facility based on eligible trade receivables. At June 30, 2015, MPLX had no borrowings and no letters of credit outstanding under its $1 billion credit agreement.

Employees

New collective bargaining agreements for the hourly refinery workers at our Canton, Catlettsburg and Texas City refineries were ratified in March and April, 2015. The agreements for Canton and Catlettsburg are scheduled to expire on January 31, 2019, and the agreement for Texas City is scheduled to expire on March 31, 2019. The labor agreement for our Galveston Bay refinery was ratified on June 23, 2015 and will expire on January 31, 2019.

Stock Split

On April 29, 2015, our Board of Directors approved a two-for-one stock split in the form of a stock dividend, which was distributed on June 10, 2015 to shareholders of record at the close of business on May 20, 2015. The total number of authorized common shares and common stock par value remained unchanged. All historical share and per share data included in this report has been retroactively restated on a post-split basis.

The above discussion contains forward-looking statements with respect to the impact of the acquisition of Hess’ Retail Operations and Related Assets, the proposed transaction between MPLX and MWE, the estimated construction costs and completion of the SAX pipeline project and the share repurchase authorizations. Factors that could affect the impact of the acquisition of Hess’ Retail Operations and Related Assets include, but are not limited to, our ability to successfully integrate the acquired Hess retail operations and achieve the strategic and other expected objectives related to the acquisition. Factors that could affect the proposed transaction between MPLX and MWE include, but are not limited to, the ability of MPLX and MWE to complete the proposed transaction on anticipated terms and timetable, the ability to obtain approval of the proposed transaction by the unitholders of MWE and satisfy other conditions to the closing of the transaction contemplated by the merger agreement, the ability to obtain governmental approvals of the proposed transaction based on the proposed terms and schedule, and any conditions imposed on the combined company in connection with consummation of the proposed transaction. Factors that could affect the estimated construction costs, timing and completion of the SAX pipeline project, include, but are not limited to, availability of materials and labor, unforeseen hazards such as weather conditions, delays in obtaining or conditions imposed by necessary government and third party approvals and other risks customarily associated with construction projects. Factors that could affect the share repurchase authorizations and the timing of any repurchases include, but are not limited to, business conditions, availability of liquidity and the market price of our common stock. These factors, among others, could cause actual results to differ materially from those set forth in the forward-looking statements.

Overview of Segments

Refining & Marketing

Refining & Marketing segment income from operations depends largely on our Refining & Marketing gross margin and refinery throughputs.

Our Refining & Marketing gross margin is the difference between the prices of refined products sold and the costs of crude oil and other charge and blendstocks refined, including the costs to transport these inputs to our refineries and the costs of products purchased for resale. The crack spread is a measure of the difference between market prices for refined products and crude oil, commonly used by the industry as a proxy for the refining margin. Crack spreads can fluctuate significantly, particularly when prices of refined products do not move in the same relationship as the cost of crude oil. As a performance benchmark and a comparison with other industry participants, we calculate Midwest (Chicago) and USGC crack spreads that we believe most closely track our operations and slate of products. Light Louisiana Sweet (“LLS”) prices and a 6-3-2-1 ratio of products (6 barrels of LLS crude oil producing 3 barrels of unleaded regular gasoline, 2 barrels of ultra-low sulfur diesel and 1 barrel of three percent residual fuel oil) are used for these crack-spread calculations.

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Refined product prices have historically moved relative to international crude oil prices like Brent crude. In recent years, domestic U.S. crude oils, such as West Texas Intermediate (“WTI”) and LLS, traded at prices less than Brent due to the growth in U.S. crude oil production, logistical constraints and other market factors. These price discounts compared to Brent favorably impacted the LLS 6-3-2-1 crack spread. During the first half of 2013, WTI traded at prices significantly less than Brent and LLS, which favorably impacted our Refining & Marketing gross margin. The differential between WTI and LLS significantly narrowed during the second half of 2013 with a further narrowing broadly continuing until late 2014. Since late 2014, LLS has seen volatile differentials to both WTI and Brent. The spread between domestic crude oils and Brent could narrow further if there is a change in existing U.S. energy policy regarding crude oil exports, or if low crude oil prices reduce U.S. crude oil production growth substantially. If either were to occur, it could reduce our Refining & Marketing gross margin.

Our refineries can process significant amounts of sour crude oil, which typically can be purchased at a discount to sweet crude oil. The amount of this discount, the sweet/sour differential, can vary significantly, causing our Refining & Marketing gross margin to differ from crack spreads based on sweet crude oil. In general, a larger sweet/sour differential will enhance our Refining & Marketing gross margin.

Future crude oil differentials will be dependent on a variety of market and economic factors, as well as U.S. energy policy.

The following table provides sensitivities showing an estimated change in annual net income due to potential changes in market conditions.

(In millions, after-tax)
LLS 6-3-2-1 crack spread sensitivity(a) (per $1.00/barrel change)	$	450
Sweet/sour differential sensitivity(b)(per $1.00/barrel change)	200
LLS-WTI differential sensitivity(c)(per $1.00/barrel change)	100
Natural gas price sensitivity (per $1.00/million British thermal unit change)	140

^(a)  Weighted 38 percent Chicago and 62 percent USGC LLS 6-3-2-1 crack spreads and assumes all other differentials and pricing relationships remain unchanged.

^(b)  LLS (prompt) - [delivered cost of sour crude oil: Arab Light, Kuwait, Maya, Western Canadian Select and Mars].

^(c)  Assumes 20 percent of crude oil throughput volumes are WTI-based domestic crude oil.

In addition to the market changes indicated by the crack spreads, the sweet/sour differential and the discount of WTI to LLS, our Refining & Marketing gross margin is impacted by factors such as:

• the types of crude oil and other charge and blendstocks processed;

• our refinery yields;

• the selling prices realized for refined products;

• the impact of commodity derivative instruments used to hedge price risk;

• the cost of products purchased for resale;

• the potential impact of lower of cost or market adjustments to inventories in periods of declining prices; and

• the impact of liquidations of last in, first out (“LIFO”) inventory layers with costs significantly above current market prices.

Inventories are stated at the lower of cost or market. The cost of our crude oil and refined product inventories is determined under the LIFO method. During periods of rapidly declining prices, the LIFO cost basis of our crude oil and refined product inventories may have to be written down to market value.

During the first quarter of 2015, we recognized a permanent reduction in our refined product inventories for LIFO accounting purposes. The cost of these inventories was based on prices in early 2014, which were much higher than current prices. As a result, we recognized a pre-tax charge of approximately $30 million in connection with this LIFO inventory reduction.

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Refining & Marketing segment income from operations is also affected by changes in refinery direct operating costs, which include turnaround and major maintenance, depreciation and amortization and other manufacturing expenses. Changes in manufacturing costs are primarily driven by the cost of energy used by our refineries, including purchased natural gas, and the level of maintenance costs. Planned major maintenance activities, or turnarounds, requiring temporary shutdown of certain refinery operating units, are periodically performed at each refinery. Costs for planned turnaround, major maintenance and engineering projects are expensed in the period incurred. We had significantly less planned turnaround and major maintenance activities at our Galveston Bay, Texas and Robinson, Illinois refineries during the first six months of 2015 compared to same period in 2014.

Speedway

Our retail marketing gross margin for gasoline and distillate, which is the price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, impacts the Speedway segment profitability. Numerous factors impact gasoline and distillate demand, including local competition, seasonal demand fluctuations, the available wholesale supply, the level of economic activity in our marketing areas and weather conditions. Market demand increases for gasoline and distillate generally increase the product margin we can realize.

The gross margin on merchandise sold at convenience stores historically has been less volatile and has contributed substantially to Speedway’s gross margin. Speedway’s convenience stores offer a wide variety of merchandise, including prepared foods, beverages and non-food items. Approximately two-thirds of Speedway’s gross margin was derived from merchandise sales in the second quarter of 2015 which is consistent with the same period of 2014. For the first six months of 2015, approximately half of Speedway’s gross margin was derived from merchandise sales compared to two-thirds in the same period of 2014. This change is the result of higher light product gross margins during the first six months of 2015 and the effects of the recently acquired Hess convenience stores.

Pipeline Transportation

The profitability of our pipeline transportation operations primarily depends on tariff rates and the volumes shipped through the pipelines. A majority of the crude oil and refined product shipments on our common carrier pipelines serve our Refining & Marketing segment. The volume of crude oil that we transport is directly affected by the supply of, and refiner demand for, crude oil in the markets served directly by our crude oil pipelines. Key factors in this supply and demand balance are the production levels of crude oil by producers in various regions or fields, the availability and cost of alternative modes of transportation, the volumes of crude oil processed at refineries and refinery and transportation system maintenance levels. The volume of refined products that we transport is directly affected by the production levels of, and user demand for, refined products in the markets served by our refined product pipelines. In most of our markets, demand for gasoline and distillate peaks during the summer driving season, which extends from May through September of each year, and declines during the fall and winter months. As with crude oil, other transportation alternatives and system maintenance levels influence refined product movements.

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Results of Operations

Consolidated Results of Operations

	Three Months Ended   June 30,									Six Months Ended   June 30,
(In millions)	2015			2014			Variance			2015			2014			Variance
Revenues and other income:
Sales and other operating revenues (including consumer excise taxes)	$	20,537		$	26,844		$	(6,307	)	$	37,728		$	50,129		$	(12,401	)
Income from equity method investments	20			57			(37		)	35			92			(57		)
Net gain (loss) on disposal of assets	(1		)	11			(12		)	4			12			(8		)
Other income	25			21			4			54			45			9
Total revenues and other income	20,581			26,933			(6,352		)	37,821			50,278			(12,457		)
Costs and expenses:
Cost of revenues (excludes items below)	16,366			23,096			(6,730		)	29,410			43,636			(14,226		)
Purchases from related parties	82			130			(48		)	158			289			(131		)
Consumer excise taxes	1,939			1,599			340			3,771			3,114			657
Depreciation and amortization	362			325			37			725			645			80
Selling, general and administrative expenses	393			316			77			751			662			89
Other taxes	104			98			6			201			202			(1		)
Total costs and expenses	19,246			25,564			(6,318		)	35,016			48,548			(13,532		)
Income from operations	1,335			1,369			(34		)	2,805			1,730			1,075
Net interest and other financial income (costs)	(64		)	(48		)	(16		)	(145		)	(94		)	(51		)
Income before income taxes	1,271			1,321			(50		)	2,660			1,636			1,024
Provision for income taxes	432			457			(25		)	918			565			353
Net income	839			864			(25		)	1,742			1,071			671
Less net income attributable to noncontrolling interests	13			9			4			25			17			8
Net income attributable to MPC	$	826		$	855		$	(29	)	$	1,717		$	1,054		$	663

Net income attributable to MPC decreased $29 million in the second quarter and increased $663 millionin the first six months of2015compared to the same periods of2014, primarily due to our Refining & Marketing segment income from operations, which decreased $54 million in the second quarter and increased $900 million in the first six months compared to the same periods of2014. Additionally, our Speedway segment income increased $33 million in the second quarter and $143 million in the first six months. The decrease for the Refining & Marketing segment in the second quarter was primarily due to a $1.18 per barrel decrease in gross margin, resulting from less favorable product price realizations compared to the spot market reference prices and less favorable crude oil acquisition costs relative to benchmark Light Louisiana Sweet crude oil. Results were also affected by a charge of $46 million to recognize increased estimated costs for compliance with the recently proposed renewable fuel standards for 2014 and 2015, particularly those for bio-mass based diesel and advanced biofuels. These decreases were almost completely offset by the favorable effects that market structure had on crude oil acquisition prices and lower direct operating costs. The year to date increase was primarily due to higher USGC crack spreads and lower turnaround and other direct operating costs. The increases in Speedway segment income for both periods were primarily the result of higher merchandise and light product margins and the addition of newly acquired locations, partially offset by higher operating and administrative expenses.

Sales and other operating revenues (including consumer excise taxes) decreased$6.31 billion in the second quarter and $12.40 billionin the first six months of2015compared to the same periods of2014. The decreases were primarily due to lower refined product sales prices partially offset by increases in refined product sales volumes. For the second quarter and first six months of 2015, average refined product sales prices decreased $1.00 per gallon and $1.07 per gallon, respectively, and refined product sales volumes increased 184 mbpd and 233 mbpd, respectively.

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Income from equity method investments decreased$37 million in the second quarter and $57 millionin the first six months of2015compared to the same periods of2014, primarily due to decreases in income from our ethanol affiliates of $27 million and $45 million, respectively, and decreases in income from LOOP of $11 million for both periods. The decreased results from our ethanol affiliates was mainly due to lower ethanol prices.

Net gain on disposal of assets decreased$12 million in the second quarter and $8 millionin the first six months of2015compared to the same periods of2014, primarily due to the sale of two terminals in the second quarter of 2014 compared to the sale of one terminal in the first quarter of 2015.

Other income increased$4 million in the second quarter and $9 millionin the first six months of2015compared to the same periods of2014, primarily due to an $11 million impairment of an investment in a company accounted for using the cost method in the second quarter of 2014, offset by gains on the sales of excess Renewable Identification Numbers (“RINs”) in the second quarter and first six months of 2015.

Cost of revenues decreased$6.73 billion in the second quarter and $14.23 billionin the first six months of2015compared to the same periods of2014. The decreases were primarily due to:

• decreases in refined product cost of sales of $6.92 billion and $14.32 billion, respectively, primarily due to decreases in raw material costs, partially offset by increases in refined product sales volumes; and

• decreases in refinery direct operating costs, including costs associated with significant planned turnaround activity, of $131 million, or $1.17 per barrel of total refinery throughput, and $633 million, or $2.58 per barrel of total refinery throughput, respectively.

Purchases from related parties decreased$48 million in the second quarter and $131 millionin the first six months of2015compared to the same periods of2014, primarily due to:

• decreases in prices and volumes for ethanol purchases from TAME, TACE, and TAAE of $51 million for the second quarter and $79 million in the first six months of 2015; and

• increase in volume purchased from LOOP and Centennial of $3 million in the second quarter and a decrease of $46 million in the first six months of 2015.

Depreciation and amortization increased$37 million in the second quarter and $80 millionin the first six months of2015compared to the same periods of2014, primarily due to depreciation of the assets acquired from Hess by our Speedway segment and projects placed into service in the Refining & Marketing segment.

Selling, general and administrative expenses increased$77 million in the second quarter and $89 millionin the first six months of2015compared to the same periods of2014 primarily due to increases in employee benefit costs, contract services and additional expenses related to the convenience stores acquired from Hess. These increases in the first six months were partially offset by decreased pension settlement expenses of $67 million.

Other taxes increased$6 million in the second quarter and decreased$1 millionin the first six months of2015compared to the same periods of2014. In the second quarter and first six months of 2015, property taxes increased, primarily attributable the Hess convenience stores acquired in September 2014, partially offset by decreases in sales and use taxes resulting from decreased maintenance work at various refineries. In the first six months, this net increase was offset by tax credits received in the first quarter of 2015.

Net interest and other financial costs increased $16 million in the second quarter and $51 millionin the first six months of2015compared to the same periods of2014 primarily due to increased borrowings on the MPC senior notes, MPLX revolver and the MPLX and MPC term loans. The MPC senior notes and term loan were used to fund the acquired Hess convenience stores in September 2014 and the MPLX revolver and term loans were used to fund its acquisitions of additional interest in Pipeline Holdings.

Provision for income taxes decreased$25 million in the second quarter and increased$353 millionin the first six months of2015compared to the same periods of2014, primarily due to a decrease of $50 million in income before income taxes in the second quarter and an increase of $1.02 billion in income before taxes for the first six months. The effective tax rates for the second quarter of both 2015 and 2014 are equivalent to or slightly less than the U.S. statutory rate of 35 percent primarily due to certain permanent benefit differences, including the domestic manufacturing deduction, partially offset by state and local tax expense.

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Segment Results

Revenues

Revenues, including intersegment sales, are summarized by segment in the following table.

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions)	2015		2014		2015		2014
Refining & Marketing	$	18,617	$	25,507	$	33,994	$	47,550
Speedway	5,331		3,909		9,862		7,368
Pipeline Transportation	164		150		314		296
Segment revenues	$	24,112	$	29,566	$	44,170	$	55,214
Items included in both revenues and costs:
Consumer excise taxes	$	1,939	$	1,599	$	3,771	$	3,114

Refining & Marketing segment revenues decreased $6.89 billion in the second quarter and $13.56 billionin the first six months of2015compared to the same periods of2014. The decreases were primarily due to decreases in refined product sales prices, partially offset by an increase in refined product sales volumes. The table below shows our Refining & Marketing segment refined product sales volumes, sales destined for export and average sales prices.

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
Refining & Marketing segment:
Refined product sales volumes (thousands of barrels per day)(a)	2,329		2,145		2,281		2,048
Refined product sales destined for export (thousands of barrels per day)	330		298		307		260
Average refined product sales prices (dollars per gallon)	$	1.98	$	2.98	$	1.86	$	2.93

^(a)  Includes intersegment sales and sales destined for export.

The table below shows the average refined product benchmark prices for our marketing areas.

	Three Months Ended   June 30,				Six Months Ended   June 30,
(Dollars per gallon)	2015		2014		2015		2014
Chicago spot unleaded regular gasoline	$	1.89	$	2.89	$	1.69	$	2.79
Chicago spot ultra-low sulfur diesel	1.81		2.96		1.74		2.98
USGC spot unleaded regular gasoline	1.85		2.80		1.69		2.73
USGC spot ultra-low sulfur diesel	1.83		2.92		1.76		2.92

Refining & Marketing intersegment sales to our Speedway segment increased $835 million in the second quarter and $1.34 billionin the first six months of2015compared to the same periods of2014. The increases in intersegment refined product sales volumes were primarily due to the acquisition of convenience stores from Hess, partially offset by lower refined product sales prices. The table below shows our Refining & Marketing intersegment sales to our Speedway segment.

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
Refining & Marketing intersegment sales to Speedway:
Intersegment sales (in millions)	$	3,425	$	2,590	$	6,158	$	4,823
Refined product sales volumes (millions of gallons)	1,473		773		2,861		1,496
Average refined product sales prices (dollars per gallon)	$	2.32	$	3.34	$	2.15	$	3.21

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Speedway segment revenues increased $1.42 billion in the second quarter and $2.49 billionin the first six months of2015compared to the same periods of2014, primarily due to increases in gasoline and distillate sales of $971 million and $1.64 billion, respectively, and increases in merchandise sales of $434 million and $823 million, respectively. The increases in gasoline and distillate sales were primarily due to volume increases of 708 million gallons and 1.37 billion gallons, respectively, primarily due to increases in the number of convenience stores resulting from the acquisition of convenience stores from Hess on September 30, 2014, partially offset by a decrease in average gasoline and distillate selling prices of $1.07 per gallon and $1.08 per gallon, respectively. The increase in merchandise sales was primarily due to an increase in the number of convenience stores.

The following table includes certain revenue statistics for the Speedway segment and includes results of the convenience stores acquired from Hess on September 30, 2014.

	Three Months Ended   June 30,						Six Months Ended   June 30,
	2015			2014			2015			2014
Convenience stores at period-end	2,755			1,492
Gasoline & distillate sales (millions of gallons)	1,514			806			2,946			1,579
Average gasoline & distillate sales prices (dollars per gallon)	$	2.59		$	3.66		$	2.45		$	3.53
Merchandise sales (in millions)	$	1,264		$	830		$	2,375		$	1,552
Same store gasoline sales volume (period over period)(b)	(0.2		%)	(1.5		%)	(0.7		%)	(1.1		%)
Same store merchandise sales (period over period)(a)(b)	4.6		%	4.6		%	5.4		%	4.9		%

^(a)  Excludes cigarettes.

^(b)  Same store comparison includes only locations owned at least 13 months, and therefore excludes locations acquired from Hess.

Pipeline Transportation segment revenue increased $14 million in the second quarter and $18 millionin the first six months of2015compared to the same periods of2014, primarily due to higher average tariffs received on crude oil and refined products shipped and higher throughput volumes. Crude oil pipeline throughput volumes increased 91 mbpd in the second quarter and 71 mbpd for the six months and refined products pipeline throughput volumes increased 70 mbpd and 68 mbpd, respectively.

The following table includes throughput volumes for the Pipeline Transportation segment.

	Three Months Ended   June 30,		Six Months Ended   June 30,
	2015	2014	2015	2014
Pipeline Throughputs (thousands of barrels per day):(a)
Crude oil pipelines	1,385	1,294	1,304	1,233
Refined products pipelines	941	871	913	845
Total	2,326	2,165	2,217	2,078

^(a)  On owned common-carrier pipelines, excluding equity method investments.

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Income from Operations

Income before income taxes and income from operations by segment are presented in the following table.

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Income from Operations by segment
Refining & Marketing	$	1,206		$	1,260		$	2,522		$	1,622
Speedway	127			94			295			152
Pipeline Transportation(a)	79			81			146			153
Items not allocated to segments:
Corporate and other unallocated items(a)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses	(1		)	(5		)	(2		)	(69		)
Income from operations	1,335			1,369			2,805			1,730
Net interest and other financial income (costs)	(64		)	(48		)	(145		)	(94		)
Income before income taxes	$	1,271		$	1,321		$	2,660		$	1,636

^(a)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

Refining & Marketing segment income from operations decreased $54 million in the second quarter and increased $900 millionin the first six months of2015compared to the same periods of2014. The decrease in the second quarter was primarily due to a $1.18 per barrel decrease in gross margin, resulting from less favorable product price realizations compared to the spot market reference prices and less favorable crude oil acquisition costs relative to benchmark Light Louisiana Sweet crude oil. Results were also affected by a charge of $46 million to recognize increased estimated costs for compliance with the recently proposed renewable fuel standards for 2014 and 2015, particularly those for bio-mass based diesel and advanced biofuels. These decreases were almost completely offset by the favorable effects that market structure had on crude oil acquisition prices and lower direct operating costs. The year to date increase was primarily due to higher USGC crack spreads and lower turnaround and other direct operating costs.

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The following table presents certain market indicators that we believe are helpful in understanding the results of our Refining & Marketing segment’s business.

	Three Months Ended   June 30,				Six Months Ended   June 30,
(Dollars per barrel)	2015		2014		2015		2014
Chicago LLS 6-3-2-1 crack spread(a)(b)	$	10.56	$	11.90	$	9.78	$	10.38
USGC LLS 6-3-2-1 crack spread(a)	10.05		9.48		10.09		8.40
Blended 6-3-2-1 crack spread(a)(c)	10.24		10.40		9.97		9.15
LLS	62.94		105.55		57.96		104.93
WTI	57.95		102.99		53.34		100.84
LLS—WTI crude oil differential(a)	4.99		2.56		4.62		4.09
Sweet/Sour crude oil differential(a)(d)	4.92		6.39		5.99		7.29

^(a)  All spreads and differentials are measured against prompt LLS.

^(b)  Calculation utilizes USGC three percent residual fuel oil price as a proxy for Chicago three percent residual fuel oil price.

^(c)  Blended Chicago/USGC crack spread is 38 percent/62 percent based on our refining capacity by region.

^(d)  LLS (prompt) - [delivered cost of sour crude oil: Arab Light, Kuwait, Maya, Western Canadian Select and Mars].

Based on the market indicators above and our refinery throughputs, we estimate the following impacts on Refining & Marketing segment income from operations for the second quarter and first six months of2015compared to the same periods of2014:

• The USGC LLS 6-3-2-1 crack spread increased $0.57 per barrel for the second quarter and $1.69 per barrel for the first six months, which had a positive impact on segment income of $127 million for the second quarter and $513 million for the first six months.

• The Chicago LLS 6-3-2-1 crack spread decreased $1.34 per barrel for the second quarter which had a negative impact on segment income of $41 million for the second quarter. The spread decreased $0.60 per barrel for the first six months, however, volume increases offset the narrowing crack spread resulting in a positive impact on segment income of $37 million for the first six months.

• The sweet/sour crude oil differential decreased by $1.47 per barrel for the second quarter and $1.30 per barrel for the first six months which had a negative impact on segment income of $88 million for the second quarter and $33 million for the first six months. In both periods, the narrowing differentials were partially offset by increased volumes.

• The LLS-WTI crude oil differential increased $2.43 per barrel for the second quarter and $0.53 per barrel for the first six months had a positive impact on segment income of $93 million for the second quarter and $67 million for the first six months.

The above market indicators use spot market values and an estimated mix of crude purchases and product sales. Differences in our results compared to these market indicators, including product price realizations, mix and crude costs as well as other items like refinery yields and other feedstock variances, had estimated negative impacts on Refining & Marketing segment income of $458 million for the second quarter and $565 million for the first six months of2015compared to the same periods of2014.

The following table summarizes our refinery throughputs.

	Three Months Ended   June 30,		Six Months Ended   June 30,
	2015	2014	2015	2014
Refinery Throughputs (thousands of barrels per day):
Crude oil refined	1,789	1,674	1,731	1,563
Other charge and blendstocks	162	158	171	178
Total	1,951	1,832	1,902	1,741
Sour crude oil throughput percent	55	54	55	52
WTI-priced crude oil throughput percent	19	17	20	19

Crude oil throughputs increased 115 mbpd in the second quarter and 168 mbpd in the first six months of2015compared to the same periods of2014, primarily due to higher planned turnaround and major maintenance activity at the Robinson refinery in the second quarter of 2014 and the Galveston Bay refinery in the first six months of 2014.

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The following table includes certain key operating statistics for the Refining & Marketing segment.

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
Refining & Marketing gross margin (dollars per barrel)(a)	$	14.84	$	16.02	$	15.47	$	15.28
Refinery direct operating costs (dollars per barrel):(b)
Planned turnaround and major maintenance	$	0.66	$	0.94	$	0.73	$	1.98
Depreciation and amortization	1.33		1.39		1.38		1.47
Other manufacturing(c)	3.94		4.77		4.08		5.32
Total	$	5.93	$	7.10	$	6.19	$	8.77

^(a)  Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.

^(b)  Per barrel of total refinery throughputs.

^(c)  Includes utilities, labor, routine maintenance and other operating costs.

Refinery direct operating costs decreased $1.17 per barrel in the second quarter and $2.58 per barrel in the first six months of2015compared to the same periods of2014, reflecting decreases in planned turnaround and major maintenance costs of $0.28 per barrel and $1.25 per barrel, respectively, and decreases in other manufacturing costs of $0.83 per barrel and $1.24 per barrel, respectively. The decreases in planned turnaround and major maintenance costs were primarily attributable to significant turnaround costs incurred by the Robinson refinery in the second quarter of 2014 and the Galveston Bay refinery in the first six months of 2014. The decreases in other manufacturing costs were primarily attributable to lower costs for energy, catalyst and routine maintenance.

We purchase RINs to satisfy a portion of our Renewable Fuel Standard compliance. Our expense associated with purchased RINs increased to $75 million in the second quarter and $117 million in the first six months of2015 from $22 million in the second quarter and $93 million in the first six months of2014, primarily due to $46 million charge in the second quarter to recognize increased estimated costs for compliance with the recently proposed renewable fuel standards for 2014 and 2015, particularly those for bio-mass based diesel and advanced biofuels. For the first six months, this increase was partially offset by lower average costs of biodiesel RINs.

The following table includes margin statistics for the Speedway segment.

	Three Months Ended   June 30,						Six Months Ended   June 30,
	2015			2014			2015			2014
Gasoline & distillate gross margin (dollars per gallon)(a)	$	0.1351		$	0.1282		$	0.1652		$	0.1220
Merchandise gross margin (in millions)	$	359		$	224		$	670		$	416
Merchandise gross margin percent	28.5		%	27.1		%	28.2		%	26.8		%

^(a)  The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.

Speedway segment income from operations increased $33 million in the second quarter and $143 millionin the first six months of2015compared to the same periods of2014. The increases in segment income were primarily due to increases in our merchandise gross margin of $135 million and $254 million, respectively, and increases in our gasoline and distillate gross margin of $101 million, or $0.0069 per gallon, and $294 million, or $0.0432 per gallon, respectively, partially offset by higher operating and administrative expenses. Merchandise, gasoline and distillate gross margins along with operating and administrative expenses were higher primarily due to the results of the acquired convenience stores from Hess.

Pipeline Transportation segment income from operations decreased $2 million in the second quarter and $7 millionin the first six months of2015compared to the same periods of2014, primarily due to lower equity affiliate income and increases in various operating expenses, partially offset by an increase in pipeline transportation revenue reflecting higher crude and refined product throughput across the system.

Corporate and other unallocated items increased $15 million in the second quarter of 2015, largely due to increased annual pension expense resulting from updates to actuarial estimates. In addition, for the first six months of 2015, the $28 million increase also reflected lower allocated employee benefit costs.

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We recorded pretax pension settlement expenses of $1 million in the second quarter and $2 million in the first six months of2015 compared to $5 million in the second quarter and $69 million in the first six months of2014 resulting from the level of employee lump sum retirement distributions that occurred during those periods.

Liquidity and Capital Resources

Cash Flows

Our cash and cash equivalents balance was $1.88 billion at June 30, 2015 compared to $1.49 billion at December 31, 2014. Net cash provided by (used in) operating activities, investing activities and financing activities for the first six months of 2015 and 2014 are presented in the following table.

	Six Months Ended   June 30,
(In millions)	2015			2014
Net cash provided by (used in):
Operating activities	$	2,184		$	1,644
Investing activities	(856		)	(681		)
Financing activities	(941		)	(1,130		)
Total	$	387		$	(167	)

Net cash provided by operating activities increased$540 million in the first six months of 2015 compared to the first six months of 2014 primarily due to an increase in net income of $671 million, partially offset by an unfavorable change in working capital of $200 million. Changes in working capital were a net $292 million use of cash in the first six months of 2015 compared to a net $92 million use of cash in the first six months of 2014. The net $292 million use of cash in the first six months of 2015 was primarily due to a decrease in accounts payable and accrued liabilities, partially offset by decreases in current receivables and inventory. The above changes in working capital exclude changes in short-term debt. Changes from December 31, 2014 to June 30, 2015 per the consolidated balance sheets were as follows:

• Accounts payable decreased$436 million from year-end 2014, primarily due to lower crude oil prices.

• Current receivables decreased$182 million from year-end 2014, primarily due to lower refined product and crude oil prices.

• Inventories decreased$102 million from year-end 2014, primarily due to decreases in crude oil and refined productinventory volumes.

The net $92 million use of cash from working capital changes in the first six months of 2014 was primarily due to increases in inventories and current receivables, partially offset by an increase in accounts payable. Changes from December 31, 2013 to June 30, 2014 per the consolidated balance sheets were as follows:

• Inventories increased $932 million from year-end 2013, primarily due to an increase in crude oil inventory volumes.

• Current receivables increased $166 million from year-end 2013, primarily due to higher crude oil and refined product prices, partially offset by lower outstanding refined product volumes.

• Accounts payable increased $700 million from year-end 2013, primarily due to higher crude oil payable prices and volumes.

Net cash used in investing activities was $175 million higher in the first six months of 2015 compared to the first six months of 2014, primarily due to an increase in additions to property, plant and equipment, partially offset by a decrease in acquisitions and investments in affiliates.

The consolidated statements of cash flows exclude changes to the consolidated balance sheets that did not affect cash. A reconciliation of additions to property, plant and equipment to reported total capital expenditures and investments follows.

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	Six Months Ended   June 30,
(In millions)	2015			2014
Additions to property, plant and equipment per consolidated statements of cash flows	$	764		$	569
Non-cash additions to property, plant and equipment	4			4
Acquisitions	—			27
Asset retirement expenditures	—			1
Decrease in capital accruals	(20		)	(31		)
Total capital expenditures	748			570
Investments in equity method investees	149			164
Total capital expenditures and investments	$	897		$	734

Capital expenditures and investments are summarized by segment below.

	Six Months Ended   June 30,
(In millions)	2015		2014
Refining & Marketing	$	436	$	413
Speedway	145		76
Pipeline Transportation	238		194
Corporate and Other(a)	78		51
Total	$	897	$	734

^(a)  Includes capitalized interest of $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

Net cash used for additions to property, plant and equipment increased $195 million for the first six months of 2015 compared to the first six months of 2014, primarily due to increases in capital expenditures in our Speedway and Pipeline Transportation segments. The increase in capital expenditures for our Speedway segment is primarily due to the conversion of convenience stores acquired from Hess in September 2014. The increase in capital expenditures for our Pipeline Transportation segment primarily reflects increased spending on the Robinson butane cavern, Patoka tank farm expansion and Cornerstone pipeline projects. Net cash used in equity method investments decreased $16 million for the first six months of 2015 compared to the first six months of 2014, primarily due to our acquisition of an additional seven percent interest in Explorer for $77 million and contributions to North Dakota Pipeline of $75 million to fund our portion of the Sandpiper pipeline project in the first six months of 2014, as compared to our contributions to Illinois Extension Pipeline of $94 million to fund the SAX pipeline project and $44 million to North Dakota Pipeline to fund our portion of the Sandpiper pipeline project in the first six months of 2015.

Financing activities were a net $941 million use of cash in the first six months of 2015 compared to a net $1.13 billion use of cash in the first six months of 2014. The uses of cash for both periods included common stock repurchases under our share repurchase authorizations and dividend payments offset by sources of cash from net borrowing activity. In addition, in the first six months of 2015, uses of cash also included a significant portion of the contingent consideration payment to the seller of the Galveston Bay refinery.

Long-term debt borrowings and repayments were a net $101 million source of cash in the first six months of 2015 compared to a net $244 million source of cash in the first six months of 2014. During the first six months of 2015, MPLX used proceeds from its $500 million of MPLX Senior Notes to repay $385 million outstanding under the MPLX Credit Agreement. During the first six months of 2014, MPLX borrowed $270 million under its revolving credit facility to fund MPLX’s acquisition of an additional interest in Pipe Line Holdings.

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Cash used in common stock repurchases decreased $531 million in the first six months of 2015 compared to the first six months of 2014. The table below summarizes our total share repurchases for these periods. See Note 8 to the unaudited consolidated financial statements for further discussion of the share repurchase authorizations.

	Six Months Ended   June 30,
(In millions, except per share data)	2015		2014
Number of shares repurchased	12		26
Cash paid for shares repurchased	$	617	$	1,148
Effective average cost per delivered share	$	49.75	$	43.91

Cash used in dividend payments increased $27 million in the first six months of 2015 compared to the first six months of 2014, primarily due to an $0.08 per share increase in our quarterly dividend payment, partially offset by a decrease in the number of outstanding shares of our common stock attributable to share repurchases. Our dividend payments were $0.50 per common share in the first six months of 2015 compared to $0.42 per common share in the first six months of 2014.

Derivative Instruments

See Item 3. Quantitative and Qualitative Disclosures about Market Risk for a discussion of derivative instruments and associated market risk.

Capital Resources

Our liquidity totaled $5.58 billion at June 30, 2015 consisting of:

	June 30, 2015
(In millions)	Total Capacity		Outstanding Borrowings		Available Capacity
Revolving credit agreement(a)	$	2,500	$	—	$	2,500
Trade receivables securitization facility(b)	1,203		—		1,203
Total	$	3,703	$	—	$	3,703
Cash and cash equivalents					1,881
Total liquidity					$	5,584

^(a)  Excludes MPLX’s $1 billion revolving credit agreement, which had $1 billion available as of June 30, 2015.

^(b)  Availability under our $1.3 billion trade receivables securitization facility is a function of eligible trade receivables, which will be lower in a sustained lower price environment for refined products. As of July 31, 2015, eligible trade receivables supported borrowings of $906 million.

Because of the alternatives available to us, including internally generated cash flow and access to capital markets, we believe that our short-term and long-term liquidity is adequate to fund not only our current operations, but also our near-term and long-term funding requirements, including capital spending programs, the repurchase of shares of our common stock, dividend payments, defined benefit plan contributions, repayment of debt maturities and other amounts that may ultimately be paid in connection with contingencies.

The MPC term loan agreement (the “Term Loan Agreement”), MPC Credit Agreement and MPLX Credit Agreement contain representations and warranties, affirmative and negative covenants and events of default that we consider usual and customary for agreements of these types. The financial covenant included in the Term Loan Agreement and the MPC Credit Agreement requires us to maintain, as of the last day of each fiscal quarter, a ratio of Consolidated Net Debt to Total Capitalization (as defined in the Term Loan Agreement and the MPC Credit Agreement) of no greater than 0.65 to 1.00. As of June 30, 2015, we were in compliance with this debt covenant with a ratio of Consolidated Net Debt to Total Capitalization of 0.30 to 1.00, as well as the other covenants contained in the Term Loan Agreement and the MPC Credit Agreement.

The financial covenant included in the MPLX Credit Agreement requires MPLX to maintain a ratio of Consolidated Total Debt (as defined in the MPLX Credit Agreement) as of the end of each fiscal quarter to Consolidated EBITDA (as defined in the MPLX Credit Agreement) for the prior four fiscal quarters of not greater than 5.0 to 1.0 (or 5.5 to 1.0 during the six-month period following certain acquisitions). Consolidated EBITDA is subject to adjustments for certain acquisitions completed and capital projects undertaken during the relevant period. As of June 30, 2015, MPLX was in compliance with this debt covenant with a ratio of Consolidated Total Debt to Consolidated EBITDA of 3.1 to 1.0, as well as the other covenants contained in the MPLX Credit Agreement.

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Our intention is to maintain an investment grade credit profile. As of June 30, 2015, the credit ratings on our senior unsecured debt were at or above investment grade level as follows.

Rating Agency	Rating
Moody’s	Baa2 (stable outlook)
Standard & Poor’s	BBB (stable outlook)
Fitch	BBB (stable outlook)

The ratings reflect the respective views of the rating agencies. Although it is our intention to maintain a credit profile that supports an investment grade rating, there is no assurance that these ratings will continue for any given period of time. The ratings may be revised or withdrawn entirely by the rating agencies if, in their respective judgments, circumstances so warrant.

Neither the Term Loan Agreement, MPC Credit Agreement, MPLX Credit Agreement nor our trade receivables securitization facility contain credit rating triggers that would result in the acceleration of interest, principal or other payments in the event that our credit ratings are downgraded. However, any downgrades of our senior unsecured debt ratings would increase the applicable interest rates, yields and other fees payable under the Term Loan Agreement, the MPC Credit Agreement and our trade receivables securitization facility. In addition, a downgrade of our senior unsecured debt rating to below investment grade levels could, under certain circumstances, decrease the amount of trade receivables that are eligible to be sold under our trade receivables securitization facility, impact our ability to purchase crude oil on an unsecured basis and could result in us having to post letters of credit under existing transportation services agreements.

Debt-to-Total-Capital Ratio

Our debt-to-total capital ratio (total debt to total debt-plus-equity) was 35 percent at June 30, 2015 and 37 percent at December 31, 2014.

(In millions)	June 30, 2015			December 31, 2014
Long-term debt due within one year	$	780		$	27
Long-term debt	5,918			6,575
Total debt	$	6,698		$	6,602
Calculation of debt-to-total-capital ratio:
Total debt	$	6,698		$	6,602
Total equity	12,290			11,390
Total capital	$	18,988		$	17,992
Debt-to-total-capital ratio	35		%	37		%

Capital Requirements

We have a capital and investment budget for 2015 of $2.53 billion, excluding capitalized interest. This budget also does not include the $675 million contribution to MPLX in connection with the pending merger with MWE. The budget includes spending on refining, retail marketing, transportation, logistics and brand marketing projects as well as amounts designated for corporate activities. During the six months ended June 30, 2015, our capital expenditures and investments were $881 million, excluding capitalized interest. There have been no material changes to our 2015 capital and investment budget since our Annual Report on Form 10-K for the year ended December 31, 2014 was filed. We continuously evaluate our capital budget and make changes as conditions warrant.

During 2014, we worked on a front-end engineering and design study and procured certain long lead time items for a residual fuel hydrocracker project at our Garyville refinery, with estimated total costs of $2.2 billion to $2.5 billion, intended to increase margins by upgrading residual fuel to ULSD and gas oil. We are deferring a final investment decision on this project as we further evaluate the implications of current market conditions on the project. As of June 30, 2015, we have capitalized $136 million of costs associated with this project. If a decision is made to not pursue this project, there could be a future impairment of the costs incurred for the project.

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Pursuant to the purchase and sale agreement for the Galveston Bay Refinery and Related Assets, we may be required to pay the seller a contingent earnout of up to an additional $700 million over six years, subject to certain conditions. In June 2015 and July 2014, we paid $189 million and $180 million for the first and second year’s contingent earnout, respectively. We currently estimate the fair value of the remaining payments to be $307 million. See Note 14 to the unaudited consolidated financial statements.

Centennial experienced a significant reduction in shipment volumes in the second half of 2011 that has continued through the second quarter of 2015. At June 30, 2015, Centennial was not shipping product. As a result, we continued to evaluate the carrying value of our equity investment in Centennial. We concluded that no impairment was required given our assessment of its fair value based on market participant assumptions for various potential uses and future cash flows of Centennial’s assets. If market conditions were to change and the owners of Centennial are unable to find an alternative use for the assets, there could be a future impairment of our Centennial interest. As of June 30, 2015, our equity investment in Centennial was $36 million and we had a $36 million guarantee associated with 50 percent of Centennial’s outstanding debt. See Note 21 to the unaudited consolidated financial statements for additional information on the debt guarantee.

During the six months ended June 30, 2015, we did not make any contributions to our funded pension plans. While we have no required contributions, we may make additional contributions to our funded pension plans in 2015 depending on the anticipated funding status and plan asset performance.

On July 29, 2015, our board of directors approved a dividend of $0.32 per share on common stock, a 28 percent increase in its quarterly dividend over the first quarter of 2015, after adjusting to reflect the two-for-one stock split that occurred in the second quarter. The dividend is payable September 10, 2015, to shareholders of record as of the close of business on August 19, 2015.

During the first six months of 2015, we paid $617 million to acquire 12 million common shares through open market share repurchases. The effective average cost was $49.75 per delivered share. At June 30, 2015, we also had agreements to repurchase additional common shares for $9 million, which were settled in July 2015. As of June 30, 2015, we had $1.11 billion of remaining share repurchase authorization. On July 29, 2015, our board of directors approved an additional $2.0 billion share repurchase authorization expiring in July 2017. See Note 8 to the unaudited consolidated financial statements.

We may utilize various methods to effect additional share repurchases, which could include open market purchases, negotiated block transactions, accelerated share repurchases or open market solicitations for shares, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future share repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be discontinued at any time.

The above discussion contains forward-looking statements with respect to a decision on the residual fuel hydrocracker project at our Garyville refinery, the contingent earnout payment to the seller of the Galveston Bay Refinery and Related Assets, the carrying value of our Centennial equity investment, future contributions to our funded pension plans and share repurchases. Forward-looking statements about our capital requirements are based on current expectations, estimates and projections and are not guarantees of future performance. Factors that could cause actual results to differ materially from those included in our forward-looking statements regarding capital requirements include the availability of liquidity, business conditions, a further decline or improvement in the long-term outlook of the potential uses of Centennial’s assets and the pursuit of different strategic alternatives for such assets, market price of our common stock, prices of and demand for crude oil and refinery feedstocks and refined products, actions of competitors, delays in obtaining necessary third-party approvals, changes in labor, materials, and equipment costs and availability, planned and unplanned outages, the delay of, cancellation of or failure to implement planned capital projects, project cost overruns, disruptions or interruptions of our refining operations due to the shortage of skilled labor and unforeseen hazards such as weather conditions, acts of war or terrorist acts and the governmental or military response, and other operating and economic considerations. These factors, among others, could cause actual results to differ materially from those set forth in the forward-looking statements.

Contractual Cash Obligations

As of June 30, 2015, our contractual cash obligations included long-term debt, capital and operating lease obligations, purchase obligations and other long-term liabilities. During the first six months of 2015, our long-term debt commitments increased $154 million. The increase was due to the issuance of MPLX senior notes, partially offset by the repayment of the MPLX Credit Agreement.

There were no other material changes to our contractual cash obligations outside the ordinary course of business.

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Off-Balance Sheet Arrangements

Off-balance sheet arrangements comprise those arrangements that may potentially impact our liquidity, capital resources and results of operations, even though such arrangements are not recorded as liabilities under accounting principles generally accepted in the United States. Our off-balance sheet arrangements are limited to indemnities and guarantees that are described below. Although these arrangements serve a variety of our business purposes, we are not dependent on them to maintain our liquidity and capital resources, and we are not aware of any circumstances that are reasonably likely to cause the off-balance sheet arrangements to have a material adverse effect on liquidity and capital resources.

We have provided various guarantees related to equity method investees. In conjunction with our spinoff from Marathon Oil, we entered into various indemnities and guarantees to Marathon Oil. These arrangements are described in Note 21 to the unaudited consolidated financial statements.

Our opinions concerning liquidity and capital resources and our ability to avail ourselves in the future of the financing options mentioned in the above forward-looking statements are based on currently available information. If this information proves to be inaccurate, future availability of financing may be adversely affected. Factors that affect the availability of financing include our performance (as measured by various factors, including cash provided by operating activities), the state of worldwide debt and equity markets, investor perceptions and expectations of past and future performance, the global financial climate, and, in particular, with respect to borrowings, the levels of our outstanding debt and credit ratings by rating agencies. The discussion of liquidity and capital resources above also contains forward-looking statements regarding expected capital and investment spending. The forward-looking statements about our capital and investment budget are based on current expectations, estimates and projections and are not guarantees of future performance. Actual results may differ materially from these expectations, estimates and projections and are subject to certain risks, uncertainties and other factors, some of which are beyond our control and are difficult to predict. Some factors that could cause actual results to differ materially include prices of and demand for crude oil and refinery feedstocks and refined products, actions of competitors, delays in obtaining necessary third-party approvals, changes in labor, materials, and equipment costs and availability, planned and unplanned outages, the delay of, cancellation of or failure to implement planned capital projects, project cost overruns, disruptions or interruptions of our refining operations due to the shortage of skilled labor and unforeseen hazards such as weather conditions, acts of war or terrorist acts and the governmental or military response, and other operating and economic considerations.

Transactions with Related Parties

We believe that transactions with related parties were conducted under terms comparable to those with unrelated parties.

Environmental Matters and Compliance Costs

We have incurred and may continue to incur substantial capital, operating and maintenance, and remediation expenditures as a result of environmental laws and regulations. If these expenditures, as with all costs, are not ultimately reflected in the prices of our products and services, our operating results will be adversely affected. We believe that substantially all of our competitors must comply with similar environmental laws and regulations. However, the specific impact on each competitor may vary depending on a number of factors, including the age and location of its operating facilities, marketing areas, production processes and whether it is also engaged in the petrochemical business or the marine transportation of crude oil and refined products.

On March 3, 2014, the U.S. Environmental Protection Agency (“EPA”) signed the final Tier 3 fuel standards. The final Tier 3 fuel standards require, among other things, a lower annual average sulfur level in gasoline to no more than 10 parts per million (“ppm”) beginning in calendar year 2017. In addition, gasoline refiners and importers may not exceed a maximum per-gallon sulfur standard of 80 ppm while retailers may not exceed a maximum per-gallon sulfur standard of 95 ppm. We anticipate that we will spend an estimated $750 million to $1 billion between 2014 and 2019 for capital expenditures necessary to comply with these standards.

There have been no other significant changes to our environmental matters and compliance costs during the six months ended June 30, 2015.

Critical Accounting Estimates

There have been no significant changes to our critical accounting estimates during the six months ended June 30, 2015.

Accounting Standards Not Yet Adopted

As discussed in Note 2 to our Consolidated Financial Statements, certain new financial accounting pronouncements will be effective for our financial statements in the future.

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Item 3. Quantitative and Qualitative Disclosures about Market Risk

For a detailed discussion of our risk management strategies and our derivative instruments, see Item 7A. Quantitative and Qualitative Disclosures about Market Risk in our Annual Report on Form 10-K for the year ended December 31, 2014.

See Notes 14 and 15 to the unaudited consolidated financial statements for more information about the fair value measurement of our derivatives, as well as the amounts recorded in our consolidated balance sheets and statements of income. We do not designate any of our commodity derivative instruments as hedges for accounting purposes.

Sensitivity analysis of the effects on income from operations (“IFO”) of hypothetical 10 percent and 25 percent increases and decreases in commodity prices for open commodity derivative instruments as of June 30, 2015 is provided in the following table.

	Change in IFO from a Hypothetical Price Increase of						Change in IFO from a Hypothetical Price Decrease of
(In millions)	10%			25%			10%			25%
As of June 30, 2015
Crude	$	(70	)	$	(174	)	$	78		$	199
Refined products	15			37			(15		)	(37		)

We remain at risk for possible changes in the market value of commodity derivative instruments; however, such risk should be mitigated by price changes in the underlying physical commodity. Effects of these offsets are not reflected in the above sensitivity analysis.

We evaluate our portfolio of commodity derivative instruments on an ongoing basis and add or revise strategies in anticipation of changes in market conditions and in risk profiles. Changes to the portfolio after June 30, 2015 would cause future IFO effects to differ from those presented above.

Sensitivity analysis of the effect of a hypothetical 100-basis-point change in interest rates on long-term debt, including the portion classified as current and excluding capital leases, as of June 30, 2015 is provided in the following table. Fair value of cash and cash equivalents, receivables, accounts payable and accrued interest approximate carrying value and are relatively insensitive to changes in interest rates due to the short-term maturity of the instruments. Accordingly, these instruments are excluded from the table.

(In millions)	Fair Value as of June 30, 2015(a)		Change in Fair Value(b)		Change in Net Income for the Three Months Ended June 30, 2015(c)
Long-term debt
Fixed-rate	$	5,587	$	556	n/a
Variable-rate	950		n/a		5

^(a)  Fair value was based on market prices, where available, or current borrowing rates for financings with similar terms and maturities.

^(b)  Assumes a 100-basis-point decrease in the weighted average yield-to-maturity at June 30, 2015.

^(c)  Assumes a 100-basis-point change in interest rates. The change to net income was based on the weighted average balance of debt outstanding for the six months ended June 30, 2015.

At June 30, 2015, our portfolio of long-term debt was comprised of fixed-rate instruments and variable-rate borrowings under the Term Loan Agreement and the MPLX term loan agreement. There were no borrowings under the MPLX Credit Agreement as of June 30, 2015. The fair value of our fixed-rate debt is relatively sensitive to interest rate fluctuations. Our sensitivity to interest rate declines and corresponding increases in the fair value of our debt portfolio unfavorably affects our results of operations and cash flows only when we elect to repurchase or otherwise retire fixed-rate debt at prices above carrying value. Interest rate fluctuations generally do not impact the fair value of borrowings under the Term Loan Agreement and the MPLX Credit Agreement, but may affect our results of operations and cash flows.

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Item 4. Controls and Procedures

Disclosure Controls and Procedures

An evaluation of the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rules 13(a)-15(e) and 15(d)-15(e) under the Securities Exchange Act of 1934, as amended) was carried out under the supervision and with the participation of our management, including our chief executive officer and chief financial officer. Based upon that evaluation, the chief executive officer and chief financial officer concluded that the design and operation of these disclosure controls and procedures were effective as of June 30, 2015, the end of the period covered by this report.

Internal Control over Financial Reporting and Changes in Internal Control over Financial Reporting

During the quarter ended June 30, 2015, there were no changes in our internal control over financial reporting that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Income from Operations by segment
Refining & Marketing	$	1,206		$	1,260		$	2,522		$	1,622
Speedway	127			94			295			152
Pipeline Transportation(a)	79			81			146			153
Items not allocated to segments:
Corporate and other unallocated items(a)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses	(1		)	(5		)	(2		)	(69		)
Income from operations	$	1,335		$	1,369		$	2,805		$	1,730
Capital Expenditures and Investments(b)
Refining & Marketing	$	207		$	235		$	436		$	413
Speedway	100			44			145			76
Pipeline Transportation	157			64			238			194
Corporate and Other(c)	49			20			78			51
Total	$	513		$	363		$	897		$	734

^(a)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(b)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

^(c)  Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

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Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
MPC Consolidated Refined Product Sales Volumes (thousands of barrels per day)(a)(b)	2,341		2,154		2,294		2,059
Refining & Marketing Operating Statistics
Refining & Marketing refined product sales volume (thousands of barrels per day)(c)	2,329		2,145		2,281		2,048
Refining & Marketing gross margin (dollars per barrel)(d)	$	14.84	$	16.02	$	15.47	$	15.28
Crude oil capacity utilization percent(e)	103		98		100		91
Refinery throughputs (thousands of barrels per day):(f)
Crude oil refined	1,789		1,674		1,731		1,563
Other charge and blendstocks	162		158		171		178
Total	1,951		1,832		1,902		1,741
Sour crude oil throughput percent	55		54		55		52
WTI-priced crude oil throughput percent	19		17		20		19
Refined product yields (thousands of barrels per day):(f)
Gasoline	896		852		904		844
Distillates	631		610		592		562
Propane	38		37		37		36
Feedstocks and special products	331		288		315		255
Heavy fuel oil	28		27		29		28
Asphalt	58		51		53		47
Total	1,982		1,865		1,930		1,772
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.66	$	0.94	$	0.73	$	1.98
Depreciation and amortization	1.33		1.39		1.38		1.47
Other manufacturing(h)	3.94		4.77		4.08		5.32
Total	$	5.93	$	7.10	$	6.19	$	8.77
Refining & Marketing Operating Statistics By Region - Gulf Coast
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	1,093		1,031		1,062		946
Other charge and blendstocks	172		156		176		183
Total	1,265		1,187		1,238		1,129
Sour crude oil throughput percent	67		67		68		64
WTI-priced crude oil throughput percent	7		2		6		3
Refined product yields (thousands of barrels per day):(i)
Gasoline	511		500		517		494
Distillates	408		390		375		355
Propane	27		25		26		23
Feedstocks and special products	320		270		314		258
Heavy fuel oil	11		16		13		15
Asphalt	14		13		14		10
Total	1,291		1,214		1,259		1,155
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.51	$	0.57	$	0.65	$	2.11
Depreciation and amortization	1.06		1.13		1.10		1.19
Other manufacturing(h)	3.75		4.77		3.87		5.28
Total	$	5.32	$	6.47	$	5.62	$	8.58

49

Supplementary Statistics (Unaudited)
	Three Months Ended   June 30,						Six Months Ended   June 30,
	2015			2014			2015			2014
Refining & Marketing Operating Statistics By Region – Midwest
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	696			643			669			617
Other charge and blendstocks	36			45			36			46
Total	732			688			705			663
Sour crude oil throughput percent	36			34			35			34
WTI-priced crude oil throughput percent	39			40			41			43
Refined product yields (thousands of barrels per day):(i)
Gasoline	385			352			387			350
Distillates	223			220			217			207
Propane	13			13			13			14
Feedstocks and special products	54			60			39			47
Heavy fuel oil	18			11			17			13
Asphalt	44			38			39			37
Total	737			694			712			668
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.89		$	1.53		$	0.82		$	1.62
Depreciation and amortization	1.72			1.75			1.78			1.83
Other manufacturing(h)	4.00			4.47			4.24			4.97
Total	$	6.61		$	7.75		$	6.84		$	8.42
Speedway Operating Statistics(b)
Convenience stores at period-end	2,755			1,492
Gasoline and distillate sales (millions of gallons)	1,514			806			2,946			1,579
Gasoline and distillate gross margin (dollars per gallon)(j)	$	0.1351		$	0.1282		$	0.1652		$	0.1220
Merchandise sales (in millions)	$	1,264		$	830		$	2,375		$	1,552
Merchandise gross margin (in millions)	$	359		$	224		$	670		$	416
Merchandise gross margin percent	28.5		%	27.1		%	28.2		%	26.8		%
Same store gasoline sales volume (period over period)(k)	(0.2		%)	(1.5		%)	(0.7		%)	(1.1		%)
Same store merchandise sales (period over period)(k)(l)	4.6		%	4.6		%	5.4		%	4.9		%
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day):(m)
Crude oil pipelines	1,385			1,294			1,304			1,233
Refined products pipelines	941			871			913			845
Total	2,326			2,165			2,217			2,078

^(a)  Total average daily volumes of refined product sales to wholesale, branded and retail (Speedway segment) customers.

^(b)  Includes the impact of Hess’ Retail Operations and Related Assets beginning on the September 30, 2014 acquisition date.

^(c)  Includes intersegment sales.

^(d)  Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.

^(e)  Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities.

^(f)  Excludes inter-refinery volumes of 46 mbpd and 43 mbpd for the three months ended June 30, 2015 and 2014, respectively, and 41 mbpd and 51 mbpd for the six months ended June 30, 2015 and 2014.

^(g)  Per barrel of total refinery throughputs.

^(h)  Includes utilities, labor, routine maintenance and other operating costs.

⁽ⁱ⁾  Includes inter-refinery transfer volumes.

^(j)  The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.

^(k)  Same store comparison includes only locations owned at least 13 months, and therefore excludes locations acquired from Hess.

^(l)  Excludes cigarettes.

^(m)   On owned common-carrier pipelines, excluding equity method investments.

50

Part II – Other Information

Item 1. Legal Proceedings

We are the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Specific matters discussed below are either new proceedings or material developments in proceedings previously reported.

Litigation

In July 2015, a purported class action lawsuit asserting claims challenging the proposed merger of MPLX and MWE was filed in the Court of Chancery of the State of Delaware by a purported unitholder of MWE. The lawsuit alleges that the individual members of the board of directors of MarkWest Energy GP, L.L.C. the general partner of MWE, breached their fiduciary and/or contractual duties to the unitholders of MWE and that MPLX, MPC and Sapphire Holdco LLC, a subsidiary of MPLX, aided and abetted those breaches. The complaint seeks to enjoin the proposed merger or, if the merger is consummated, to rescind the transaction or recover rescission damages. The lawsuit also seeks an accounting and recovery of attorneys’ fees, experts’ fees, and other litigation costs. We believe the allegations in the complaint are without merit.

In May 2015, the Kentucky attorney general filed a lawsuit against our wholly owned subsidiary, Marathon Petroleum Company LP (“MPCLP”) in the United States District Court for the Western District of Kentucky asserting claims under federal and state antitrust statutes, the Kentucky Consumer Protection Act, and state common law. The complaint, as amended in July 2015, alleges that MPCLP used deed restrictions, supply agreements with customers and exchange agreements with competitors to unreasonably restrain trade in areas within Kentucky and seeks declaratory relief, unspecified damages, civil penalties, restitution and disgorgement of profits. At this early stage, the ultimate outcome of this litigation remains uncertain, and neither the likelihood of an unfavorable outcome nor the ultimate liability, if any, can be determined, and we are unable to estimate a reasonably possible loss (or range of loss) for this matter. We intend to vigorously defend ourselves in this matter.

We are a party to a number of lawsuits and other proceedings and cannot predict the outcome of every such matter with certainty. While it is possible that an adverse result in one or more of the lawsuits or proceedings in which we are a defendant could be material to us, based upon current information and our experience as a defendant in other matters, we believe that these lawsuits and proceedings, individually or in the aggregate, will not have a material adverse effect on our consolidated results of operations, financial position or cash flows.

Environmental Proceedings

As reported in our Annual Report on Form 10-K for the year ended December 31, 2014, in January 2011, the EPA notified us of alleged violations of various statutory and regulatory provisions related to motor fuels, some of which we had previously self-reported to the EPA. Subsequently, we self-reported four additional alleged Clean Air Act violations related to motor fuels to the EPA. In July 2014, we tentatively agreed to pay a $2.75 million civil penalty as well as undertake certain projects to reduce emissions and retire sulfur credits. In August and December 2014, we self-reported three similar alleged violations to the EPA. The EPA agreed to include these incidents in the consent decree and increased the civil penalty to $2.9 million. We finalized the consent decree with the agency in May 2015.

We are involved in a number of other environmental proceedings arising in the ordinary course of business. While the outcome and impact on us cannot be predicted with certainty, we believe the resolution of these environmental proceedings will not have a material adverse effect on our consolidated results of operations, financial position or cash flows.

Item 1A. Risk Factors

We are subject to various risks and uncertainties in the course of our business. The discussion of such risks and uncertainties may be found under Item 1A. Risk Factors in our Annual Report on Form 10-K for the year ended December 31, 2014.

51

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

On April 29, 2015 the Company announced a two-for-one stock split in the form of a stock dividend (the "Stock Split"). The record date for the Stock Split was May 20, 2015, and the additional shares were distributed on June 10, 2015. Each shareholder of record on the close of business on the record date received one additional share of common stock for each share held. All share and per share data presented herein reflects the impact of the Stock Split, as appropriate.

The following table sets forth a summary of our purchases during the quarter ended June 30, 2015, of equity securities that are registered by MPC pursuant to Section 12 of the Securities Exchange Act of 1934, as amended.

Period	Total Number of Shares Purchased(a)	Average Price Paid per Share(b)		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs	Maximum Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs(c)
04/01/2015-04/30/2015	1,379,146	$	50.14	1,257,506	$	1,454,310,653
05/01/2015-05/31/2015	1,170,186	51.27		1,170,186	1,394,311,607
06/01/2015-06/30/2015	5,579,600	51.10		5,578,854	1,109,219,633
Total	8,128,932	50.96		8,006,546

^(a)  The amounts in this column include 121,640 and 746 shares of our common stock delivered by employees to MPC, upon vesting of restricted stock, to satisfy tax withholding requirements in April and June, respectively.

^(b)  Amounts in this column reflect the weighted average price paid for shares purchased under our share repurchase authorizations and for shares tendered to us in satisfaction of employee tax withholding obligations upon the vesting of restricted stock granted under our stock plans. The weighted average price includes commissions paid to brokers on shares purchased under our share repurchase authorizations.

^(c)  As of June 30, 2015, we had approximately $1.11 billion of share repurchase authorization remaining. On July 29, 2015, our board of directors approved an additional $2.0 billion share repurchase authorization expiring on July 31, 2017, resulting in $10.0 billion of total share repurchase authorizations since January 1, 2012.

52

Item 6. Exhibits

			Incorporated by Reference			Filed Herewith	Furnished Herewith
Exhibit Number	Exhibit Description	Form	Exhibit	Filing Date	SEC File No.
2.1*	Agreement and Plan of Merger, dated as of July 11, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation.	8-K	2.1	7/16/2015	001-35054
3.1	Restated Certificate of Incorporation of Marathon Petroleum Corporation	8-K	3.1	6/22/2011	001-35054
3.2	Amended and Restated Bylaws of Marathon Petroleum Corporation	10-Q	3.2	8/8/2012	001-35054
10.1	First Amendment to the Marathon Petroleum Corporation Amended and Restated 2011 Incentive Compensation Plan					X
10.2	First Amendment to the Marathon Petroleum Corporation 2012 Incentive Compensation Plan					X
31.1	Certification of President and Chief Executive Officer pursuant to Rule 13(a)-14 and 15(d)-14 under the Securities Exchange Act of 1934					X
31.2	Certification of Senior Vice President and Chief Financial Officer pursuant to Rule 13(a)-14 and 15(d)-14 under the Securities Exchange Act of 1934					X
32.1	Certification of President and Chief Executive Officer pursuant to 18 U.S.C. Section 1350						X
32.2	Certification of Senior Vice President and Chief Financial Officer pursuant to 18 U.S.C. Section 1350						X
101.INS	XBRL Instance Document					X
101.SCH	XBRL Taxonomy Extension Schema					X
101.PRE	XBRL Taxonomy Extension Presentation Linkbase					X
101.CAL	XBRL Taxonomy Extension Calculation Linkbase					X
101.DEF	XBRL Taxonomy Extension Definition Linkbase					X
101.LAB	XBRL Taxonomy Extension Label Linkbase					X

* Certain schedules and exhibits to this agreement have been omitted pursuant to Item 601(b)(2) of Regulation S-K. A copy of any omitted schedule and/or exhibit will be furnished supplementally to the SEC upon request.

53

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

August 3, 2015	MARATHON PETROLEUM CORPORATION
	By:	/s/ John J. Quaid
		John J. Quaid Vice President and Controller

54

EX-10.1

Exhibit 10.1

FIRST AMENDMENT TO

THE MARATHON PETROLEUM CORPORATION

AMENDED AND RESTATED 2011 INCENTIVE COMPENSATION PLAN

WHEREAS, the Board of Directors (“Board”) of the Marathon Petroleum Corporation (“Corporation”) has adopted the Marathon Petroleum Corporation amended and restated 2011 Incentive Compensation Plan (“2011 Plan”) for the benefit of 2011 Plan participants and to retain employees and directors with a high degree of training, experience and ability; to attract new employees and directors whose services are considered particularly valuable; to encourage the sense of proprietorship of such persons; and to promote the active interest of such persons in the development and financial success of the Corporation; and

WHEREAS, the Board adopted the Marathon Petroleum Corporation 2012 Incentive Compensation Plan, effective as of April 25, 2012 (“2012 Plan”); and

WHEREAS, the Board determined that there shall be no new equity grants issued under the 2011 Plan after April 25, 2012 and that all future equity grants are to be issued under the 2012 Plan; and

WHEREAS, on April 29, 2015 the Board approved a two-for-one stock split of the Corporation’s common stock to be effected as a 100% stock dividend and directed that the stock dividend be distributed on June 10, 2015; and

WHEREAS, on April 29, 2015, the Board directed that the 2011 Plan be amended effective as of June 10, 2015 to reflect the effect of the stock dividend of one additional share of the Corporation’s common stock for every one share of common stock issued; and

WHEREAS, paragraph 12 of the 2011 Plan permits the Board to amend the 2011 Plan from time to time, subject only to certain limitations specified therein, none of which are applicable to this amendment; and

WHEREAS, this amendment will not require shareholder approval because it does not represent a material revision to the 2011 Plan; and

WHEREAS, the Board authorized any officer of the Corporation to adopt such amendment on behalf of the Board.

NOW, THEREFORE, the following amendment is hereby made part of the 2011 Plan, effective as of June 10, 2015:

FIRST AND ONLY CHANGE

The introductory paragraph in paragraph 4 of the 2011 Plan is hereby deleted in its entirety and replaced with the following new paragraph to increase the aggregate number of shares of common stock issuable thereunder:

Common Stock Available for Awards. Subject to the provisions of paragraph 14 hereof, there shall be available for Awards under this Plan granted wholly or partly in Common Stock (including rights or options that may be exercised for or settled in Common Stock) an aggregate of 50 million shares of Common Stock. No more than 20 million shares of Common Stock may be the subject of Awards that are not Options or Stock Appreciation Rights. In the sole discretion of the Committee, 20 million shares of Common Stock may be granted as Incentive Stock Options.

IN WITNESS WHEREOF, the Corporation has executed this First Amendment to the Marathon Petroleum Corporation 2011 Incentive Compensation Plan.

MARATHON PETROLEUM CORPORATION
By:	/s/ Rodney P. Nichols
Name:	Rodney P. Nichols
Title:	Senior Vice President Human Resources and Administrative Services
Date:	June 8, 2015

EX-10.2

Exhibit 10.2

FIRST AMENDMENT TO

THE MARATHON PETROLEUM CORPORATION

2012 INCENTIVE COMPENSATION PLAN

WHEREAS, the Board of Directors (“Board”) of the Marathon Petroleum Corporation (“Corporation”) has adopted the Marathon Petroleum Corporation 2012 Incentive Compensation Plan (“Plan”) for the benefit of Plan participants and to retain employees and directors with a high degree of training, experience and ability; to attract new employees and directors whose services are considered particularly valuable; to encourage the sense of proprietorship of such persons; and to promote the active interest of such persons in the development and financial success of the Corporation; and

WHEREAS, on April 29, 2015 the Board approved a two-for-one stock split of the Corporation’s common stock to be effected as a 100% stock dividend and directed that the stock dividend be distributed on June 10, 2015; and

WHEREAS, on April 29, 2015, the Board directed that the Plan be amended effective as of June 10, 2015 to reflect the effect of the stock dividend of one additional share of the Corporation’s common stock for every one share of common stock issued; and

WHEREAS, paragraph 12 of the Plan permits the Board to amend the Plan from time to time, subject only to certain limitations specified therein, none of which are applicable to this amendment; and

WHEREAS, this amendment will not require shareholder approval because it does not represent a material revision of the Plan; and

WHEREAS, the Board authorized any officer of the Corporation to adopt such amendment on behalf of the Board.

NOW, THEREFORE, the following amendment is hereby made part of the Plan, effective as of June 10, 2015:

FIRST AND ONLY CHANGE

The introductory paragraph in paragraph 4 of the Plan is hereby deleted in its entirety and replaced with the following new paragraph to increase the aggregate number of shares of common stock issuable thereunder:

Common Stock Available for Awards. Subject to the provisions of paragraph 14 hereof, there shall be available for Awards under this Plan granted wholly or partly in Common Stock (including rights or options that may be exercised for or settled in Common Stock) an aggregate of 50 million shares of Common Stock. No more than 20 million shares of Common Stock may be the subject of Awards that are not Options or Stock Appreciation Rights. In the sole discretion of the Committee, 20 million shares of Common Stock may be granted as Incentive Stock Options.

IN WITNESS WHEREOF, the Corporation has executed this First Amendment to the Marathon Petroleum Corporation 2012 Incentive Compensation Plan.

MARATHON PETROLEUM CORPORATION
By:	/s/ Rodney P. Nichols
Name:	Rodney P. Nichols
Title:	Senior Vice President Human Resources and Administrative Services
Date:	June 8, 2015

EX-31.1

Exhibit 31.1

MARATHON PETROLEUM CORPORATION

CERTIFICATION PURSUANT TO SECTION 302 OF

THE SARBANES-OXLEY ACT OF 2002

I, Gary R. Heminger, certify that:

1. I have reviewed this report on Form 10-Q of Marathon Petroleum Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date:	August 3, 2015	/s/ Gary R. Heminger
		Gary R. Heminger
		President and Chief Executive Officer

EX-31.2

Exhibit 31.2

MARATHON PETROLEUM CORPORATION

CERTIFICATION PURSUANT TO SECTION 302 OF

THE SARBANES-OXLEY ACT OF 2002

I, Timothy T. Griffith, certify that:

1. I have reviewed this report on Form 10-Q of Marathon Petroleum Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date:	August 3, 2015	/s/ Timothy T. Griffith
		Timothy T. Griffith
		Senior Vice President and Chief Financial Officer

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Marathon Petroleum Corporation (the “Company”) on Form 10-Q for the period ending June 30, 2015 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Gary R. Heminger, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

August 3, 2015

/s/ Gary R. Heminger

Gary R. Heminger

President and Chief Executive Officer

EX-32.2

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Marathon Petroleum Corporation (the “Company”) on Form 10-Q for the period ending June 30, 2015 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Timothy T. Griffith, Senior Vice President and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

August 3, 2015

/s/ Timothy T. Griffith

Timothy T. Griffith

Senior Vice President and Chief Financial Officer

XML

Other Items (Tables)

6 Months Ended

Jun. 30, 2015

Other Income and Expenses [Abstract]

Net Interest And Other Financial Income (Costs)

Net interest and other financial income (costs) was:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Interest income	$	2		$	1		$	3		$	3
Interest expense	(69		)	(49		)	(149		)	(98		)
Interest capitalized	8			7			16			13
Other financial costs	(5		)	(7		)	(15		)	(12		)
Net interest and other financial income (costs)	$	(64	)	$	(48	)	$	(145	)	$	(94	)

XML

Acquisitions and Investments (Schedule of Acquisition Related Pro Forma Financial Information) (Details) - Jun. 30, 2014 - USD ($) $ / shares in Units, $ in Millions	Total	Total
Business Combinations [Abstract]
Sales and other operating revenues (including consumer excise taxes)	$ 29,931	$ 55,948
Net income attributable to MPC	$ 869	$ 1,051
Net income attributable to MPC per share – basic	$ 1.51	$ 1.81
Net income attributable to MPC per share – diluted	$ 1.50	$ 1.80

XML

Stock-Based Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock Option Award Activity

The following table presents a summary of our stock option award activity for the six months ended June 30, 2015:

	Number of Shares		Weighted Average Exercise Price
Outstanding at December 31, 2014	9,502,876		$	22.74
Granted	1,094,676		50.89
Exercised	(1,492,710	)	17.49
Forfeited, canceled or expired	(48,766	)	39.84
Outstanding at June 30, 2015	9,056,076		26.91

Summary of Restricted Stock Award Activity

The following table presents a summary of restricted stock award activity for the six months ended June 30, 2015:

	Shares of Restricted Stock (“RS”)				Restricted Stock Units (“RSU”)
	Number of Shares		Weighted Average Grant Date Fair Value		Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	1,030,146		$	38.62	822,186		$	18.65
Granted	505,698		50.86		23,831		48.65
RS’s Vested/RSU’s Issued	(516,406	)	34.12		(944	)	34.26
Forfeited	(34,396	)	39.22		(850	)	44.77
Outstanding at June 30, 2015	985,042		47.24		844,223		19.45

Schedule of Performance Unit Awards

The following table presents a summary of the activity for performance unit awards to be settled in shares for the six months ended June 30, 2015:

	Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	5,791,825		$	0.88
Granted	2,389,450		0.95
Settled	(2,035,833	)	0.85
Outstanding at June 30, 2015	6,145,442		0.92

XML

Other Items - Net Interest And Other Financial Income (Costs) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Income and Expenses [Abstract]
Interest income	$ 2	$ 1	$ 3	$ 3
Interest expense	(69)	(49)	(149)	(98)
Interest capitalized	8	7	16	13
Other financial costs	(5)	(7)	(15)	(12)
Net interest and other financial income (costs)	$ 64	$ 48	$ 145	$ 94

XML

Acquisitions and Investments (Acquisition of Biodiesel Facility) (Details) - Felda Iffco Sdn Bhd [Member] gallons_per_year in Millions, $ in Millions	1 Months Ended
	Apr. 30, 2014 USD ($)	Apr. 01, 2014 gallons_per_year
Business Acquisition [Line Items]
Cash paid for acquisition	$ 40
Plant capacity volume | gallons_per_year		60

XML

Fair Value Measurements - Reconciliation of Net Beginning and Ending Balances Recorded for Net Assets and Liabilities Classified as Level 3 (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 490	$ 639	$ 478	$ 625
Contingent consideration payment	(189)	0	(189)	0
Unrealized and realized losses included in net income	6	8	18	22
Ending balance	$ 307	$ 647	$ 307	$ 647

XML

Accumulated Other Comprehensive Loss (Tables)

6 Months Ended

Jun. 30, 2015

Equity [Abstract]

Changes in Accumulated Other Comprehensive Loss by Component

The following table shows the changes in accumulated other comprehensive loss by component. Amounts in parentheses indicate debits.

(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2013	$	(161	)	$	(50	)	$	4	$	3		$	(204	)
Other comprehensive income (loss) before reclassifications	(65		)	8			—		(1		)	(58		)
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			1			—		—			27
– settlement loss(a)	69			—			—		—			69
Tax effect	(28		)	1			—		—			(27		)
Other comprehensive income (loss)	(21		)	8			—		(1		)	(14		)
Balance as of June 30, 2014	$	(182	)	$	(42	)	$	4	$	2		$	(218	)

(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2014	$	(217	)	$	(104	)	$	4	$	4		$	(313	)
Other comprehensive loss before reclassifications	(12		)	14			—		(2		)	—
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			4			—		—			30
– settlement loss(a)	2			—			—		—			2
Tax effect	(2		)	(1		)	—		—			(3		)
Other comprehensive income (loss)	(9		)	15			—		(2		)	4
Balance as of June 30, 2015	$	(226	)	$	(89	)	$	4	$	2		$	(309	)

^(a)  These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 19.

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Description of the Business and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2015

Accounting Policies [Abstract]

Use of estimates

These interim consolidated financial statements are unaudited; however, in the opinion of our management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal, recurring nature unless otherwise disclosed. These interim consolidated financial statements, including the notes, have been prepared in accordance with the rules of the Securities and Exchange Commission applicable to interim period financial statements and do not include all of the information and disclosures required by United States generally accepted accounting principles (“U.S. GAAP”) for complete financial statements.

Inventories

Inventories are carried at the lower of cost or market value. The cost of inventories of crude oil and refinery feedstocks, refined products and merchandise is determined primarily under the last-in, first-out (“LIFO”) method.

Derivative instruments

Derivatives that are not designated as accounting hedges may include commodity derivatives used to hedge price risk on (1) inventories, (2) fixed price sales of refined products, (3) the acquisition of foreign-sourced crude oil and (4) the acquisition of ethanol for blending with refined products.

Stock-based compensation arrangements

The fair value of stock options granted to our employees is estimated on the date of the grant using the Black Scholes option-pricing model, which employs various assumptions.

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Fair Value Measurements Fair Value Measurements - Nonrecurring (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	$ 0	$ 0
Other asset impairment charges	$ 0	$ 11

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Inventories - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Inventory Disclosure [Abstract]
Impact on revenues and costs as a result of LIFO liquidations	$ (30)	$ 0

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Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				$ (313)	$ (204)
Other comprehensive loss before reclassifications				0	(58)
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]			(25)	(25)
Amortization - actuarial loss	[1]			30	27
Amortization - settlement loss	[1]			2	69
Tax effect				(3)	(27)
Other comprehensive income (loss)		$ 4	$ (13)	4	(14)
Ending balance		(309)	(218)	(309)	(218)
Accumulated Defined Benefit Plans Adjustment | Pension Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(217)	(161)
Other comprehensive loss before reclassifications				(12)	(65)
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]			(23)	(23)
Amortization - actuarial loss	[1]			26	26
Amortization - settlement loss	[1]			2	69
Tax effect				(2)	(28)
Other comprehensive income (loss)				(9)	(21)
Ending balance		(226)	(182)	(226)	(182)
Accumulated Defined Benefit Plans Adjustment | Other Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(104)	(50)
Other comprehensive loss before reclassifications				14	8
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]			(2)	(2)
Amortization - actuarial loss	[1]			4	1
Amortization - settlement loss				0	0
Tax effect				(1)	1
Other comprehensive income (loss)				15	8
Ending balance		(89)	(42)	(89)	(42)
Gain on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				4	4
Other comprehensive loss before reclassifications				0	0
Amounts reclassified from accumulated other comprehensive loss:
Tax effect				0	0
Other comprehensive income (loss)				0	0
Ending balance		4	4	4	4
Workers Compensation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				4	3
Other comprehensive loss before reclassifications				(2)	(1)
Amounts reclassified from accumulated other comprehensive loss:
Tax effect				0	0
Other comprehensive income (loss)				(2)	(1)
Ending balance		$ 2	$ 2	$ 2	$ 2

[1] These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 19.

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Variable Interest Entity (Details) $ in Millions	Jun. 30, 2015 USD ($)
Illinois Extension Pipeline Company LLC | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE, maximum loss exposure, amount	$ 214

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Fair Value Measurements - Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash collateral netted with derivative liabilities		$ 12
Cash collateral netted with derivative assets			$ (78)
Contingent consideration, current		190	174
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - netting and collateral	[1]	(43)	(258)
Commodity derivative instruments, assets - net	[2]	18	59
Commodity derivative instruments, assets - collateral pledged not offset		20	0
Other		2	2
Total assets at fair value		20	61
Commodity derivative instruments, liabilities - netting and collateral	[1]	(55)	(180)
Commodity derivative instruments, liabilities - net	[2]	0	0
Commodity derivative instruments, liabilities - collateral pledged not offset		0	0
Contingent consideration, liability	[3]	307	478
Total liabilities at fair value		307	478
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		61	317
Other		2	2
Total assets at fair value		63	319
Commodity derivative instruments, liabilities - gross		55	180
Contingent consideration, liability		0	0
Total liabilities at fair value		55	180
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		0	0
Other		0	0
Total assets at fair value		0	0
Commodity derivative instruments, liabilities - gross		0	0
Contingent consideration, liability		0	0
Total liabilities at fair value		0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		0	0
Other		0	0
Total assets at fair value		0	0
Commodity derivative instruments, liabilities - gross		0	0
Contingent consideration, liability	[3]	307	478
Total liabilities at fair value		$ 307	$ 478

[1] Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of June 30, 2015, cash collateral of $12 million was netted with the mark-to-market derivative liabilities. As of December 31, 2014, $78 million was netted with mark-to-market derivative assets.

[2] We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.

[3] Includes $190 million and $174 million classified as current at June 30, 2015 and December 31, 2014, respectively.

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Debt - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
MPC Revolver | Letter of Credit
Line of Credit Facility [Line Items]
Borrowings outstanding	$ 0
MPC Revolver | Line of Credit
Line of Credit Facility [Line Items]
Long-term debt, gross	0	$ 0
Trade Receivables Securitization
Line of Credit Facility [Line Items]
Current borrowing capacity	1,200
Maximum borrowing capacity	1,300
MPLX Revolver | MPLX LP
Line of Credit Facility [Line Items]
Borrowings during period	$ 30
Interest rate during period	1.50%
Repayments during period	$ 415
Remaining borrowing capacity	$ 1,000
Remaining borrowing capacity, percentage	100.00%
MPLX Revolver | MPLX LP | Letter of Credit
Line of Credit Facility [Line Items]
Borrowings outstanding	$ 0
MPLX Revolver | MPLX LP | Line of Credit
Line of Credit Facility [Line Items]
Long-term debt, gross	$ 0	$ 385

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Derivatives - Classification of Gross Fair Values of Derivative Instruments, Excluding Cash Collateral (Detail) - Commodity derivatives - Other current assets - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Asset	$ 61	$ 317
Liability	$ 55	$ 180

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Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$ 130	$ 82
Net income taxes paid to taxing authorities	1,039	299
Non-cash investing and financing activities:
Property, plant and equipment sold	4	4
Property, plant and equipment acquired	$ 4	$ 4

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Fair Value Measurements - Narrative (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) $ / bbl	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Feb. 01, 2013 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized and realized losses included in net income	$ 6,000,000	$ 8,000,000	$ 18,000,000	$ 22,000,000
Fair Value, Measurements, Recurring | Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized and realized losses included in net income	0	0	0	0
Fair Value, Measurements, Recurring | Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized and realized losses included in net income	6,000,000	$ 8,000,000	18,000,000	22,000,000
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other asset impairment charges			$ 0	$ 11,000,000
Galveston Bay Refinery and Related Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maximum earnout payment, year one						$ 200,000,000
Maximum earnout payment, year two						200,000,000
Maximum earnout payment, year three						200,000,000
Maximum earnout payment, year four						250,000,000
Maximum earnout payment, year five						250,000,000
Maximum earnout payment, year six						250,000,000
Total cumulative payment capped over six-year period						$ 700,000,000
Cash paid for acquisition	$ 189,000,000				$ 180,000,000
Galveston Bay Refinery and Related Assets | Fair Value, Measurements, Recurring | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range of internal and external crack spread forecast per barrel | $ / bbl			8
Discount rate			5.00%
Galveston Bay Refinery and Related Assets | Fair Value, Measurements, Recurring | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range of internal and external crack spread forecast per barrel | $ / bbl			20
Discount rate			10.00%

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Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Combined federal, state and foreign income tax rate	34.00%	35.00%	35.00%	35.00%
Statutory rate applied to income before income taxes			35.00%
Unrecognized benefits	$ 12		$ 12

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Debt

6 Months Ended

Jun. 30, 2015

Debt Disclosure [Abstract]

Debt

Debt

Our outstanding borrowings at June 30, 2015 and December 31, 2014 consisted of the following:

(In millions)	June 30, 2015			December 31, 2014
Marathon Petroleum Corporation:
3.500% senior notes due March 1, 2016	$	750		$	750
Revolving credit agreement due 2017	—			—
Term loan agreement due 2019	700			700
5.125% senior notes due March 1, 2021	1,000			1,000
3.625% senior notes due September 15, 2024	750			750
6.500% senior notes due March 1, 2041	1,250			1,250
4.750% senior notes due September 15, 2044	800			800
5.000% senior notes due September 15, 2054	400			400
Consolidated subsidiaries:
Capital lease obligations due 2015-2028	360			372
MPLX bank revolving credit facility due 2019	—			385
MPLX term loan facility due 2019	250			250
MPLX 4.000% senior notes due February 15, 2025	500			—
Trade receivables securitization facility due 2016	—			—
Total	6,760			6,657
Unamortized debt issuance costs(a)	(38		)	(35		)
Unamortized discount	(27		)	(26		)
Fair value adjustments(b)	3			6
Amounts due within one year	(780		)	(27		)
Total long-term debt due after one year	$	5,918		$	6,575

^(a)  We adopted the updated FASB debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented. We reclassified unamortized debt issuance costs related to term debt from other noncurrent assets to long-term debt.

^(b)  The $20 million gain on the termination of our interest rate swap agreements in 2012 is being amortized over the remaining life of the 3.50 percent senior notes.

MPLX Senior Notes – On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of MPLX Senior Notes, the net proceeds of which were approximately $495 million, after deducting underwriting discounts. The net proceeds of this offering were used to repay the amounts outstanding under the MPLX revolving credit agreement (the “MPLX Credit Agreement”), as well as for general partnership purposes. Interest is payable semi-annually in arrears on February 15 and August 15 of each year, commencing on August 15, 2015.

There were no borrowings or letters of credit outstanding under the MPC revolving credit facility or the trade receivables securitization facility at June 30, 2015. As of June 30, 2015, eligible trade receivables supported available borrowings of $1.2 billion under the $1.3 billion trade receivables facility. During the six months ended June 30, 2015, MPLX borrowed $30 million under the MPLX Credit Agreement at an average interest rate of 1.5 percent, per annum, and repaid $415 million of these borrowings. At June 30, 2015, MPLX had no borrowings and no letters of credit outstanding under the MPLX Credit Agreement, resulting in total unused loan availability of $1 billion, or 100 percent of the borrowing capacity.

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MPLX LP (Detail) - Jun. 30, 2015 - MPLX LP	Total
Storage Services Butane Cavern
Noncontrolling Interest [Line Items]
Ownership interest	100.00%
General Partner and Limited Partner
Noncontrolling Interest [Line Items]
MPC's partnership interest in MPLX (in percentage)	71.50%
General Partner
Noncontrolling Interest [Line Items]
MPC's partnership interest in MPLX (in percentage)	2.00%
General Partner | MPLX Pipe Line Holdings LP
Noncontrolling Interest [Line Items]
Ownership interest	99.50%

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Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Assets and Liabilities Accounted for at Fair Value on Recurring Basis

The following tables present assets and liabilities accounted for at fair value on a recurring basis as of June 30, 2015 and December 31, 2014 by fair value hierarchy level. We have elected to offset the fair value amounts recognized for multiple derivative contracts executed with the same counterparty, including any related cash collateral as shown below; however, fair value amounts by hierarchy level are presented on a gross basis in the following tables.

	June 30, 2015
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	61	$	—	$	—	$	(43	)	$	18	$	20
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	63	$	—	$	—	$	(43	)	$	20	$	20
Commodity derivative instruments, liabilities	$	55	$	—	$	—	$	(55	)	$	—	$	—
Contingent consideration, liability(c)	—		—		307		N/A			307		—
Total liabilities at fair value	$	55	$	—	$	307	$	(55	)	$	307	$	—

	December 31, 2014
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	317	$	—	$	—	$	(258	)	$	59	$	—
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	319	$	—	$	—	$	(258	)	$	61	$	—
Commodity derivative instruments, liabilities	$	180	$	—	$	—	$	(180	)	$	—	$	—
Contingent consideration, liability(c)	—		—		478		N/A			478		—
Total liabilities at fair value	$	180	$	—	$	478	$	(180	)	$	478	$	—

^(a)  Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of June 30, 2015, cash collateral of $12 million was netted with the mark-to-market derivative liabilities. As of December 31, 2014, $78 million was netted with mark-to-market derivative assets.

^(b)  We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.

^(c)  Includes $190 million and $174 million classified as current at June 30, 2015 and December 31, 2014, respectively.

Reconciliation of Net Beginning and Ending Balances Recorded for Net Assets and Liabilities Classified as Level 3

The following is a reconciliation of the beginning and ending balances recorded for liabilities classified as Level 3 in the fair value hierarchy.

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015			2014		2015			2014
Beginning balance	$	490		$	639	$	478		$	625
Contingent consideration payment	(189		)	—		(189		)	—
Unrealized and realized losses included in net income	6			8		18			22
Ending balance	$	307		$	647	$	307		$	647

Fair Value Measurements, Nonrecurring

	Six Months Ended June 30,
	2015				2014
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Other noncurrent assets	$	—	$	—	$	—	$	11

Financial Instruments at Fair Value, Excluding Derivative Financial Instruments and Contingent Consideration

The following table summarizes financial instruments on the basis of their nature, characteristics and risk at June 30, 2015 and December 31, 2014, excluding the derivative financial instruments and contingent consideration reported above.

	June 30, 2015				December 31, 2014
(In millions)	Fair Value		Carrying Value		Fair Value		Carrying Value
Financial assets:
Investments	$	34	$	2	$	26	$	2
Other	32		31		32		32
Total financial assets	$	66	$	33	$	58	$	34
Financial liabilities:
Long-term debt(a)	$	6,537	$	6,376	$	6,571	$	6,265
Deferred credits and other liabilities	19		19		17		17
Total financial liabilities	$	6,556	$	6,395	$	6,588	$	6,282

^(a)  Excludes capital leases

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Property, Plant and Equipment Property, Plant and Equipment (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 26,007	$ 25,302
Residual Fuel Hydrocracker - Garyville | Construction in Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 136

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Subsequent Event Subsequent Event (Details) - MPLX LP $ in Millions	Jul. 11, 2015 USD ($)	Jul. 10, 2015 USD ($)	Dec. 10, 2014 USD ($)
Subsequent Event [Line Items]
General partners' contributed capital			$ 9
MarkWest | Subsequent Event
Subsequent Event [Line Items]
Date of merger agreement	Jul. 11, 2015
Common units conversion ratio	1.09
Equity interest issued or issuable, value assigned		$ 20,000
Long-term debt assumed	$ 4,200
General partners' contributed capital	$ 675

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Equity (Tables)

6 Months Ended

Jun. 30, 2015

Equity [Abstract]

Share Repurchases

Total share repurchases were as follows for the three and six months ended June 30, 2015 and 2014:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Number of shares repurchased	8		10		12		26
Cash paid for shares repurchased	$	408	$	459	$	617	$	1,148
Effective average cost per delivered share	$	50.97	$	44.07	$	49.75	$	43.91

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MPLX LP (Public Offerings) (Details) - MPLX LP - USD ($) $ / shares in Units, shares in Thousands, $ in Millions			6 Months Ended
	Feb. 12, 2015	Dec. 08, 2014	Jun. 30, 2015	Dec. 10, 2014
Noncontrolling Interest [Line Items]
Proceeds from issuance of common limited partners units		$ 221
General partners' capital account, units issued				130
General partners' contributed capital				$ 9
4.000% senior notes due two thousand twenty five | Senior Notes
Noncontrolling Interest [Line Items]
Debt instrument, face amount	$ 500
Debt instrument, interest rate	4.00%		4.00%
Debt instrument, maturity date	Feb. 15, 2025		Feb. 15, 2025
Limited Partner
Noncontrolling Interest [Line Items]
Units sold in public offering		3,500
Shares issued, price per share		$ 66.68

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Segment Information - Income From Operations Attributable To Operating Segments (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Revenues		$ 20,537	$ 26,844	$ 37,728	$ 50,129
Income from operations		1,335	1,369	2,805	1,730
Income from equity method investments		20	57	35	92
Depreciation and amortization		362	325	725	645
Capital expenditures and investments	[1],[2]	513	363	897	734
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	[3]	3,575	2,722	6,442	5,085
Operating Segments
Segment Reporting Information [Line Items]
Revenues		24,112	29,566	44,170	55,214
Income from operations	[4]	1,412	1,435	2,963	1,927
Income from equity method investments		20	57	35	92
Depreciation and amortization	[5]	349	312	699	620
Capital expenditures and investments	[6]	464	343	819	683
Refining & Marketing
Segment Reporting Information [Line Items]
Revenues		15,192	22,917	27,836	42,727
Refining & Marketing | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues		3,425	2,590	6,158	4,823
Refining & Marketing | Operating Segments
Segment Reporting Information [Line Items]
Revenues		18,617	25,507	33,994	47,550
Income from operations		1,206	1,260	2,522	1,622
Income from equity method investments		8	35	14	59
Depreciation and amortization		268	264	535	525
Capital expenditures and investments		207	235	436	413
Speedway
Segment Reporting Information [Line Items]
Revenues		5,329	3,908	9,860	7,366
Speedway | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues		2	1	2	2
Speedway | Operating Segments
Segment Reporting Information [Line Items]
Revenues		5,331	3,909	9,862	7,368
Income from operations		127	94	295	152
Income from equity method investments		0	0	0	0
Depreciation and amortization		62	29	125	57
Capital expenditures and investments		100	44	145	76
Pipeline Transportation
Segment Reporting Information [Line Items]
Revenues		16	19	32	36
Pipeline Transportation | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues		148	131	282	260
Pipeline Transportation | Operating Segments
Segment Reporting Information [Line Items]
Revenues		164	150	314	296
Income from operations	[4]	79	81	146	153
Income from equity method investments		12	22	21	33
Depreciation and amortization		19	19	39	38
Capital expenditures and investments		157	64	238	194
Reportable Segment
Segment Reporting Information [Line Items]
Revenues		$ 20,537	$ 26,844	$ 37,728	$ 50,129

[1] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

[2] Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

[3] Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties

[4] Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

[5] Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below.

[6] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

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Related Party Transactions - Payables To Related Parties (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Payables to related parties	$ 17	$ 18
Explorer
Related Party Transaction [Line Items]
Payables to related parties	4	3
LOCAP
Related Party Transaction [Line Items]
Payables to related parties	2	2
LOOP
Related Party Transaction [Line Items]
Payables to related parties	5	4
TAAE
Related Party Transaction [Line Items]
Payables to related parties	1	2
TACE
Related Party Transaction [Line Items]
Payables to related parties	2	2
TAME
Related Party Transaction [Line Items]
Payables to related parties	$ 3	$ 5

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Defined Benefit Pension and Other Postretirement Plans (Tables)

6 Months Ended

Jun. 30, 2015

Compensation and Retirement Disclosure [Abstract]

Components of Net Periodic Benefit Costs

The following summarizes the components of net periodic benefit costs:

	Three Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	28		$	20		$	7		$	6
Interest cost	18			18			8			9
Expected return on plan assets	(24		)	(26		)	—			—
Amortization – prior service credit	(11		)	(11		)	(1		)	(1		)
– actuarial loss	13			13			1			—
– settlement loss	1			5			—			—
Net periodic benefit cost	$	25		$	19		$	15		$	14

	Six Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	51		$	43		$	15		$	13
Interest cost	36			38			16			17
Expected return on plan assets	(50		)	(54		)	—			—
Amortization – prior service credit	(23		)	(23		)	(2		)	(2		)
– actuarial loss	26			26			4			1
– settlement loss	2			69			—			—
Net periodic benefit cost	$	42		$	99		$	33		$	29

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Consolidated Statement of Equity - Shares - shares shares in Millions	Total	Common Stock	Treasury Stock
Number of common shares issued (beginning balance) at Dec. 31, 2013		724
Number of shares issued - stock-based compensation		2
Number of common shares issued (ending balance) at Jun. 30, 2014		726
Number of shares held in treasury (beginning balance) at Dec. 31, 2013			(130)
Number of shares repurchased	(26)		(27)
Number of shares held in treasury (ending balance) at Jun. 30, 2014			(157)
Number of common shares issued (beginning balance) at Dec. 31, 2014	726	726
Number of shares issued - stock-based compensation		2
Number of common shares issued (ending balance) at Jun. 30, 2015	728	728
Number of shares held in treasury (beginning balance) at Dec. 31, 2014	(179)		(179)
Number of shares repurchased	(12)		(12)
Number of shares held in treasury (ending balance) at Jun. 30, 2015	(191)		(191)

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Income Per Common Share - Summary of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic earnings per share:
Net income attributable to MPC	$ 826	$ 855	$ 1,717	$ 1,054
Income allocated to participating securities	1	1	3	2
Income available to common stockholders – basic	$ 825	$ 854	$ 1,714	$ 1,052
Weighted average common shares outstanding (in shares)	541	574	543	580
Basic (in USD per share)	$ 1.52	$ 1.49	$ 3.16	$ 1.81
Diluted earnings per share:
Net income attributable to MPC	$ 826	$ 855	$ 1,717	$ 1,054
Income allocated to participating securities	1	1	3	2
Income available to common stockholders – diluted	$ 825	$ 854	$ 1,714	$ 1,052
Weighted average common shares outstanding (in shares)	541	574	543	580
Effect of dilutive securities (in shares)	3	4	4	4
Weighted average common shares, including dilutive effect (in shares)	544	578	547	584
Diluted (in USD per share)	$ 1.51	$ 1.48	$ 3.14	$ 1.80

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Derivatives (Tables)

6 Months Ended

Jun. 30, 2015

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Classification of Fair Values of Derivative Instruments, Excluding Cash Collateral

The following table presents the gross fair values of derivative instruments, excluding cash collateral, and where they appear on the consolidated balance sheets as of June 30, 2015 and December 31, 2014:

	June 30, 2015
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	61	$	55	Other current assets
	December 31, 2014
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	317	$	180	Other current assets

Open Commodity Derivative Contracts

The table below summarizes open commodity derivative contracts as of June 30, 2015.

	Position	Total Barrels (In thousands)
Crude oil(a)
Exchange-traded	Long	12,403
Exchange-traded	Short	(24,938	)
Refined Products(b)
Exchange-traded	Long	4,004
Exchange-traded	Short	(2,439	)

^(a)  96.5 percent of these contracts expire in the third quarter of 2015.

^(b)  100 percent of these contracts expire in the third quarter of 2015.

Effect of Commodity Derivative Instruments in Statements of Income

The following table summarizes the effect of all commodity derivative instruments in our consolidated statements of income:

	Gain (Loss)						Gain (Loss)
(In millions)	Three Months Ended June 30,						Six Months Ended June 30,
Income Statement Location	2015			2014			2015			2014
Sales and other operating revenues	$	(3	)	$	(2	)	$	11		$	8
Cost of revenues	(70		)	(114		)	(25		)	(175		)
Total	$	(73	)	$	(116	)	$	(14	)	$	(167	)

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Stock-Based Compensation Plans

6 Months Ended

Jun. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation Plans

Stock-Based Compensation Plans

Stock Option Awards

The following table presents a summary of our stock option award activity for the six months ended June 30, 2015:

	Number of Shares		Weighted Average Exercise Price
Outstanding at December 31, 2014	9,502,876		$	22.74
Granted	1,094,676		50.89
Exercised	(1,492,710	)	17.49
Forfeited, canceled or expired	(48,766	)	39.84
Outstanding at June 30, 2015	9,056,076		26.91

The grant date fair value of stock option awards granted during the six months ended June 30, 2015 was $13.45 per share. The fair value of stock options granted to our employees is estimated on the date of the grant using the Black Scholes option-pricing model, which employs various assumptions.

Restricted Stock Awards

The following table presents a summary of restricted stock award activity for the six months ended June 30, 2015:

	Shares of Restricted Stock (“RS”)				Restricted Stock Units (“RSU”)
	Number of Shares		Weighted Average Grant Date Fair Value		Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	1,030,146		$	38.62	822,186		$	18.65
Granted	505,698		50.86		23,831		48.65
RS’s Vested/RSU’s Issued	(516,406	)	34.12		(944	)	34.26
Forfeited	(34,396	)	39.22		(850	)	44.77
Outstanding at June 30, 2015	985,042		47.24		844,223		19.45

Performance Unit Awards

The following table presents a summary of the activity for performance unit awards to be settled in shares for the six months ended June 30, 2015:

	Number of Units		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	5,791,825		$	0.88
Granted	2,389,450		0.95
Settled	(2,035,833	)	0.85
Outstanding at June 30, 2015	6,145,442		0.92

The performance unit awards granted during the six months ended June 30, 2015 have a grant date fair value of $0.95 per unit, as calculated using a Monte Carlo valuation model.

MPLX Awards

During the six months ended June 30, 2015, MPLX granted equity-based compensation awards under the MPLX LP 2012 Incentive Compensation Plan. The compensation expense for these awards is not material to our consolidated financial statements.

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Defined Benefit Pension and Other Postretirement Plans

6 Months Ended

Jun. 30, 2015

Compensation and Retirement Disclosure [Abstract]

Defined Benefit Pension and Other Postretirement Plans

Defined Benefit Pension and Other Postretirement Plans

The following summarizes the components of net periodic benefit costs:

	Three Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	28		$	20		$	7		$	6
Interest cost	18			18			8			9
Expected return on plan assets	(24		)	(26		)	—			—
Amortization – prior service credit	(11		)	(11		)	(1		)	(1		)
– actuarial loss	13			13			1			—
– settlement loss	1			5			—			—
Net periodic benefit cost	$	25		$	19		$	15		$	14

	Six Months Ended June 30,
	Pension Benefits						Other Benefits
(In millions)	2015			2014			2015			2014
Components of net periodic benefit cost:
Service cost	$	51		$	43		$	15		$	13
Interest cost	36			38			16			17
Expected return on plan assets	(50		)	(54		)	—			—
Amortization – prior service credit	(23		)	(23		)	(2		)	(2		)
– actuarial loss	26			26			4			1
– settlement loss	2			69			—			—
Net periodic benefit cost	$	42		$	99		$	33		$	29

During the six months ended June 30, 2015, we made no contributions to our funded pension plans. We have no required funding for 2015, but may make voluntary contributions at our discretion. Current benefit payments related to unfunded pension and other postretirement benefit plans were $6 million and $12 million, respectively, during the six months ended June 30, 2015.

During the six months ended June 30, 2015 and 2014, we determined that lump sum payments to employees retiring in the respective years will exceed the plans’ total service and interest costs for the year. Settlement losses are required to be recorded when lump sum payments exceed total service and interest costs. As a result, during the six months ended June 30, 2015 and 2014, we recorded pension settlement expenses of $2 million and $69 million related to our lump sum payments made during the first six months of 2015 and 2014, respectively.

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Acquisitions and Investments (Investments in Pipeline Companies) (Details) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
	Mar. 04, 2014	Jun. 30, 2015	Jun. 30, 2015	Jul. 01, 2014
Illinois Extension Pipeline Company LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage				35.00%
Cash paid to acquire equity method investments		$ 94	$ 214
Explorer
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		25.00%	25.00%
Cash paid to acquire equity method investments	$ 77
Ownership percentage acquired	7.00%

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Debt (Tables)

6 Months Ended

Jun. 30, 2015

Debt Disclosure [Abstract]

Outstanding Borrowings

Our outstanding borrowings at June 30, 2015 and December 31, 2014 consisted of the following:

(In millions)	June 30, 2015			December 31, 2014
Marathon Petroleum Corporation:
3.500% senior notes due March 1, 2016	$	750		$	750
Revolving credit agreement due 2017	—			—
Term loan agreement due 2019	700			700
5.125% senior notes due March 1, 2021	1,000			1,000
3.625% senior notes due September 15, 2024	750			750
6.500% senior notes due March 1, 2041	1,250			1,250
4.750% senior notes due September 15, 2044	800			800
5.000% senior notes due September 15, 2054	400			400
Consolidated subsidiaries:
Capital lease obligations due 2015-2028	360			372
MPLX bank revolving credit facility due 2019	—			385
MPLX term loan facility due 2019	250			250
MPLX 4.000% senior notes due February 15, 2025	500			—
Trade receivables securitization facility due 2016	—			—
Total	6,760			6,657
Unamortized debt issuance costs(a)	(38		)	(35		)
Unamortized discount	(27		)	(26		)
Fair value adjustments(b)	3			6
Amounts due within one year	(780		)	(27		)
Total long-term debt due after one year	$	5,918		$	6,575

^(a)  We adopted the updated FASB debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented. We reclassified unamortized debt issuance costs related to term debt from other noncurrent assets to long-term debt.

^(b)  The $20 million gain on the termination of our interest rate swap agreements in 2012 is being amortized over the remaining life of the 3.50 percent senior notes.

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Commitments and Contingencies

6 Months Ended

Jun. 30, 2015

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Commitments and Contingencies

We are the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which we have not recorded an accrued liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings and discovery. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material.

Environmental matters—We are subject to federal, state, local and foreign laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites and certain other locations including presently or formerly owned or operated retail marketing sites. Penalties may be imposed for noncompliance.

At June 30, 2015 and December 31, 2014, accrued liabilities for remediation totaled $172 million and $185 million, respectively. It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties if any that may be imposed. Receivables for recoverable costs from certain states, under programs to assist companies in clean-up efforts related to underground storage tanks at presently or formerly owned or operated retail marketing sites, was $66 million and $67 million at June 30, 2015 and December 31, 2014, respectively.

We are involved in a number of environmental enforcement matters arising in the ordinary course of business. While the outcome and impact on us cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on our consolidated results of operations, financial position or cash flows.

Lawsuits—In May 2015, the Kentucky attorney general filed a lawsuit against our wholly owned subsidiary, Marathon Petroleum Company LP (“MPCLP”) in the United States District Court for the Western District of Kentucky asserting claims under federal and state antitrust statutes, the Kentucky Consumer Protection Act, and state common law. The complaint, as amended in July 2015, alleges that MPCLP used deed restrictions, supply agreements with customers and exchange agreements with competitors to unreasonably restrain trade in areas within Kentucky and seeks declaratory relief, unspecified damages, civil penalties, restitution and disgorgement of profits. At this early stage, the ultimate outcome of this litigation remains uncertain, and neither the likelihood of an unfavorable outcome nor the ultimate liability, if any, can be determined, and we are unable to estimate a reasonably possible loss (or range of loss) for this matter. We intend to vigorously defend ourselves in this matter.

In May 2007, the Kentucky attorney general filed a lawsuit against us and Marathon Oil in state court in Franklin County, Kentucky for alleged violations of Kentucky’s emergency pricing and consumer protection laws following Hurricanes Katrina and Rita in 2005. The lawsuit alleges that we overcharged customers by $89 millionduring September and October 2005. The complaint seeks disgorgement of these sums, as well as penalties, under Kentucky’s emergency pricing and consumer protection laws. We are vigorously defending this litigation. We believe that this is the first lawsuit for damages and injunctive relief under the Kentucky emergency pricing laws to progress this far and it contains many novel issues. In May 2011, the Kentucky attorney general amended his complaint to include a request for immediate injunctive relief as well as unspecified damages and penalties related to our wholesale gasoline pricing in April and May 2011 under statewide price controls that were activated by the Kentucky governor on April 26, 2011 and which have since expired. The court denied the attorney general’s request for immediate injunctive relief, and the remainder of the 2011 claims likely will be resolved along with those dating from 2005. If the lawsuit is resolved unfavorably in its entirety, it could materially impact our consolidated results of operations, financial position or cash flows. However, management does not believe the ultimate resolution of this litigation will have a material adverse effect.

We are also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to us cannot be predicted with certainty, we believe that the resolution of these other lawsuits and proceedings will not have a material adverse effect on our consolidated financial position, results of operations or cash flows.

Guarantees—We have provided certain guarantees, direct and indirect, of the indebtedness of other companies. Under the terms of most of these guarantee arrangements, we would be required to perform should the guaranteed party fail to fulfill its obligations under the specified arrangements. In addition to these financial guarantees, we also have various performance guarantees related to specific agreements.

Guarantees related to indebtedness of equity method investees—We hold interests in an offshore oil port, LOOP, and a crude oil pipeline system, LOCAP. Both LOOP and LOCAP have secured various project financings with throughput and deficiency agreements. Under the agreements, we are required to advance funds if the investees are unable to service their debt. Any such advances are considered prepayments of future transportation charges. The duration of the agreements vary but tend to follow the terms of the underlying debt, which extend through 2037. Our maximum potential undiscounted payments under these agreements for the debt principal totaled $172 million as of June 30, 2015.

We hold an interest in a refined products pipeline through our investment in Centennial, and have guaranteed our portion of the payment of Centennial’s principal, interest and prepayment costs, if applicable, under a Master Shelf Agreement, which is scheduled to expire in 2024. The guarantee arose in order for Centennial to obtain adequate financing. Our maximum potential undiscounted payments under this agreement for debt principal totaled $36 million as of June 30, 2015.

Marathon Oil indemnifications—In conjunction with our spinoff from Marathon Oil, we have entered into arrangements with Marathon Oil providing indemnities and guarantees with recorded values of $2 million as of June 30, 2015, which consist of unrecognized tax benefits related to MPC, its consolidated subsidiaries and the refining, marketing and transportation business operations prior to our spinoff which are not already reflected in the unrecognized tax benefits described in Note 11, and other contingent liabilities Marathon Oil may incur related to taxes. Furthermore, the separation and distribution agreement and other agreements with Marathon Oil to effect our spinoff provide for cross-indemnities between Marathon Oil and us. In general, Marathon Oil is required to indemnify us for any liabilities relating to Marathon Oil’s historical oil and gas exploration and production operations, oil sands mining operations and integrated gas operations, and we are required to indemnify Marathon Oil for any liabilities relating to Marathon Oil’s historical refining, marketing and transportation operations. The terms of these indemnifications are indefinite and the amounts are not capped.

Other guarantees—We have entered into other guarantees with maximum potential undiscounted payments totaling $82 million as of June 30, 2015, which primarily consist of a commitment to contribute cash to an equity method investee for certain catastrophic events, up to $50 million per event, in lieu of procuring insurance coverage and leases of assets containing general lease indemnities and guaranteed residual values.

General guarantees associated with dispositions – Over the years, we have sold various assets in the normal course of our business. Certain of the related agreements contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require us to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. We are typically not able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the underlying triggering event has little or no past experience upon which a reasonable prediction of the outcome can be based.

Contractual commitments—At June 30, 2015, our contractual commitments to acquire property, plant and equipment and advance funds to equity method investees totaled $1.7 billion, which includes $331 million of contingent consideration associated with the acquisition of the Galveston Bay Refinery and Related Assets, $659 million for contributions to North Dakota Pipeline Company LLC and $116 million for contributions to Illinois Extension Pipeline. See Note 4 for additional information on our investments in the SAX project. See Note 14 for additional information on the contingent consideration.

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Subsequent Event

6 Months Ended

Jun. 30, 2015

Subsequent Events [Abstract]

Subsequent Event

Subsequent Events

On July 11, 2015, MPLX and MarkWest Energy Partners, L.P. (“MWE”) entered into a definitive merger agreement whereby MWE would become a wholly owned subsidiary of MPLX. Under the terms of the agreement, each common unit of MWE issued and outstanding will be converted into the right to receive 1.09 common units of MPLX representing limited partner interests in MPLX, plus a one-time cash payment to MWE unitholders. As of the close of trading on Friday, July 10, 2015, the implied total enterprise value for MWE was approximately $20 billion, including the assumption of debt of approximately $4.2 billion. MPC would contribute $675 million of cash to MPLX to fund the one-time cash payment. The transaction between MPLX and MWE, which is subject to approval by MWE unitholders and to customary closing conditions and regulatory approvals, is expected to close in the fourth quarter of 2015. Following completion of the transaction, we expect to continue to consolidate MPLX’s financial results.

The combination of MarkWest and MPLX defers the need for the recently proposed sale of MPC's marine business to MPLX in 2015. As a result, that transaction has been indefinitely postponed.

In July 2015, a purported class action lawsuit asserting claims challenging the proposed merger of MPLX and MWE was filed in the Court of Chancery of the State of Delaware by a purported unitholder of MWE. The lawsuit alleges that the individual members of the board of directors of MarkWest Energy GP, L.L.C. the general partner of MWE, breached their fiduciary and/or contractual duties to the unitholders of MWE and that MPLX, MPC and Sapphire Holdco LLC, a subsidiary of MPLX, aided and abetted those breaches. The complaint seeks to enjoin the proposed merger or, if the merger is consummated, to rescind the transaction or recover rescission damages. The lawsuit also seeks an accounting and recovery of attorneys’ fees, experts’ fees, and other litigation costs. We believe the allegations in the complaint are without merit.

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Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2013	$ 11,332	$ 7	$ (4,155)	$ 9,765	$ 5,507	$ (204)	$ 412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,071				1,054		17
Dividends declared	(245)				(245)
Distributions to noncontrolling interests	(12)						(12)
Other comprehensive income (loss)	(14)					(14)
Shares repurchased	(1,148)		(1,148)	0
Shares returned - stock based compensation			(10)
Shares issued - stock based compensation				17
Net shares issued - stock based compensation	7
Stock-based compensation	37			37			0
Other	9				9
Ending balance at Jun. 30, 2014	11,037	7	(5,313)	9,819	6,325	(218)	417
Beginning balance at Dec. 31, 2014	11,390	7	(6,299)	9,841	7,515	(313)	639
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,742				1,717		25
Dividends declared	(273)				(273)
Distributions to noncontrolling interests	(18)						(18)
Other comprehensive income (loss)	4					4
Shares repurchased	(617)		(617)	0
Shares returned - stock based compensation			(10)
Shares issued - stock based compensation				26
Net shares issued - stock based compensation	16
Stock-based compensation	45			45			0
Issuance of MPLX LP common units	1						1
Ending balance at Jun. 30, 2015	$ 12,290	$ 7	$ (6,926)	$ 9,912	$ 8,959	$ (309)	$ 647

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Supplementary Statistics

6 Months Ended

Jun. 30, 2015

Text Block [Abstract]

Supplementary Statistics

Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Income from Operations by segment
Refining & Marketing	$	1,206		$	1,260		$	2,522		$	1,622
Speedway	127			94			295			152
Pipeline Transportation(a)	79			81			146			153
Items not allocated to segments:
Corporate and other unallocated items(a)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses	(1		)	(5		)	(2		)	(69		)
Income from operations	$	1,335		$	1,369		$	2,805		$	1,730
Capital Expenditures and Investments(b)
Refining & Marketing	$	207		$	235		$	436		$	413
Speedway	100			44			145			76
Pipeline Transportation	157			64			238			194
Corporate and Other(c)	49			20			78			51
Total	$	513		$	363		$	897		$	734

^(a)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(b)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

^(c)  Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
MPC Consolidated Refined Product Sales Volumes (thousands of barrels per day)(a)(b)	2,341		2,154		2,294		2,059
Refining & Marketing Operating Statistics
Refining & Marketing refined product sales volume (thousands of barrels per day)(c)	2,329		2,145		2,281		2,048
Refining & Marketing gross margin (dollars per barrel)(d)	$	14.84	$	16.02	$	15.47	$	15.28
Crude oil capacity utilization percent(e)	103		98		100		91
Refinery throughputs (thousands of barrels per day):(f)
Crude oil refined	1,789		1,674		1,731		1,563
Other charge and blendstocks	162		158		171		178
Total	1,951		1,832		1,902		1,741
Sour crude oil throughput percent	55		54		55		52
WTI-priced crude oil throughput percent	19		17		20		19
Refined product yields (thousands of barrels per day):(f)
Gasoline	896		852		904		844
Distillates	631		610		592		562
Propane	38		37		37		36
Feedstocks and special products	331		288		315		255
Heavy fuel oil	28		27		29		28
Asphalt	58		51		53		47
Total	1,982		1,865		1,930		1,772
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.66	$	0.94	$	0.73	$	1.98
Depreciation and amortization	1.33		1.39		1.38		1.47
Other manufacturing(h)	3.94		4.77		4.08		5.32
Total	$	5.93	$	7.10	$	6.19	$	8.77
Refining & Marketing Operating Statistics By Region - Gulf Coast
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	1,093		1,031		1,062		946
Other charge and blendstocks	172		156		176		183
Total	1,265		1,187		1,238		1,129
Sour crude oil throughput percent	67		67		68		64
WTI-priced crude oil throughput percent	7		2		6		3
Refined product yields (thousands of barrels per day):(i)
Gasoline	511		500		517		494
Distillates	408		390		375		355
Propane	27		25		26		23
Feedstocks and special products	320		270		314		258
Heavy fuel oil	11		16		13		15
Asphalt	14		13		14		10
Total	1,291		1,214		1,259		1,155
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.51	$	0.57	$	0.65	$	2.11
Depreciation and amortization	1.06		1.13		1.10		1.19
Other manufacturing(h)	3.75		4.77		3.87		5.28
Total	$	5.32	$	6.47	$	5.62	$	8.58

Supplementary Statistics (Unaudited)
	Three Months Ended   June 30,						Six Months Ended   June 30,
	2015			2014			2015			2014
Refining & Marketing Operating Statistics By Region – Midwest
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	696			643			669			617
Other charge and blendstocks	36			45			36			46
Total	732			688			705			663
Sour crude oil throughput percent	36			34			35			34
WTI-priced crude oil throughput percent	39			40			41			43
Refined product yields (thousands of barrels per day):(i)
Gasoline	385			352			387			350
Distillates	223			220			217			207
Propane	13			13			13			14
Feedstocks and special products	54			60			39			47
Heavy fuel oil	18			11			17			13
Asphalt	44			38			39			37
Total	737			694			712			668
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.89		$	1.53		$	0.82		$	1.62
Depreciation and amortization	1.72			1.75			1.78			1.83
Other manufacturing(h)	4.00			4.47			4.24			4.97
Total	$	6.61		$	7.75		$	6.84		$	8.42
Speedway Operating Statistics(b)
Convenience stores at period-end	2,755			1,492
Gasoline and distillate sales (millions of gallons)	1,514			806			2,946			1,579
Gasoline and distillate gross margin (dollars per gallon)(j)	$	0.1351		$	0.1282		$	0.1652		$	0.1220
Merchandise sales (in millions)	$	1,264		$	830		$	2,375		$	1,552
Merchandise gross margin (in millions)	$	359		$	224		$	670		$	416
Merchandise gross margin percent	28.5		%	27.1		%	28.2		%	26.8		%
Same store gasoline sales volume (period over period)(k)	(0.2		%)	(1.5		%)	(0.7		%)	(1.1		%)
Same store merchandise sales (period over period)(k)(l)	4.6		%	4.6		%	5.4		%	4.9		%
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day):(m)
Crude oil pipelines	1,385			1,294			1,304			1,233
Refined products pipelines	941			871			913			845
Total	2,326			2,165			2,217			2,078

^(a)  Total average daily volumes of refined product sales to wholesale, branded and retail (Speedway segment) customers.

^(b)  Includes the impact of Hess’ Retail Operations and Related Assets beginning on the September 30, 2014 acquisition date.

^(c)  Includes intersegment sales.

^(d)  Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.

^(e)  Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities.

^(f)  Excludes inter-refinery volumes of 46 mbpd and 43 mbpd for the three months ended June 30, 2015 and 2014, respectively, and 41 mbpd and 51 mbpd for the six months ended June 30, 2015 and 2014.

^(g)  Per barrel of total refinery throughputs.

^(h)  Includes utilities, labor, routine maintenance and other operating costs.

⁽ⁱ⁾  Includes inter-refinery transfer volumes.

^(j)  The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.

^(k)  Same store comparison includes only locations owned at least 13 months, and therefore excludes locations acquired from Hess.

^(l)  Excludes cigarettes.

^(m)   On owned common-carrier pipelines, excluding equity method investments.

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Derivatives - Effect of Commodity Derivative Instruments in Statements of Income (Detail) - Commodity derivatives - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ (73)	$ (116)	$ (14)	$ (167)
Sales and other operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	(3)	(2)	11	8
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ (70)	$ (114)	$ (25)	$ (175)

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Inventories (Tables)

6 Months Ended

Jun. 30, 2015

Inventory Disclosure [Abstract]

Summary Of Inventories

(In millions)	June 30, 2015		December 31, 2014
Crude oil and refinery feedstocks	$	2,147	$	2,219
Refined products	2,880		2,955
Materials and supplies	338		302
Merchandise	175		166
Total (at cost)	$	5,540	$	5,642

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Acquisitions and Investments (Acquisition of Hess' Retail Operations and Related Assets) (Details) $ in Millions	Sep. 30, 2014 USD ($) bbl / d	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 1,566	$ 1,566
Hess' Retail Operations and Related Assets
Business Acquisition [Line Items]
Allocation of space on Colonial Pipeline (in barrels per day) | bbl / d	40,000
Cash paid for acquisition	$ 2,820
Net working capital adjustment estimate	(3)
Goodwill	$ 629

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Inventories - Summary Of Inventories (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Crude oil and refinery feedstocks	$ 2,147	$ 2,219
Refined products	2,880	2,955
Materials and supplies	338	302
Merchandise	175	166
Total (at cost)	$ 5,540	$ 5,642

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Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues and other income:
Sales and other operating revenues (including consumer excise taxes)	$ 20,537	$ 26,844	$ 37,728	$ 50,129
Income from equity method investments	20	57	35	92
Net gain (loss) on disposal of assets	(1)	11	4	12
Other income	25	21	54	45
Total revenues and other income	20,581	26,933	37,821	50,278
Costs and expenses:
Cost of revenues (excludes items below)	16,366	23,096	29,410	43,636
Purchases from related parties	82	130	158	289
Consumer excise taxes	1,939	1,599	3,771	3,114
Depreciation and amortization	362	325	725	645
Selling, general and administrative expenses	393	316	751	662
Other taxes	104	98	201	202
Total costs and expenses	19,246	25,564	35,016	48,548
Income from operations	1,335	1,369	2,805	1,730
Net interest and other financial income (costs)	(64)	(48)	(145)	(94)
Income before income taxes	1,271	1,321	2,660	1,636
Provision for income taxes	432	457	918	565
Net income	839	864	1,742	1,071
Less net income attributable to noncontrolling interests	13	9	25	17
Net income attributable to MPC	$ 826	$ 855	$ 1,717	$ 1,054
Basic:
Net income attributable to MPC per share	$ 1.52	$ 1.49	$ 3.16	$ 1.81
Weighted average shares outstanding (in shares)	541	574	543	580
Diluted:
Net income attributable to MPC per share	$ 1.51	$ 1.48	$ 3.14	$ 1.80
Weighted average shares outstanding (in shares)	544	578	547	584
Dividends paid (in USD per share)	$ 0.25	$ 0.21	$ 0.50	$ 0.42

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Supplemental Cash Flow Information (Tables)

6 Months Ended

Jun. 30, 2015

Supplemental Cash Flow Elements [Abstract]

Summary of Supplemental Cash Flow Information

	Six Months Ended   June 30,
(In millions)	2015		2014
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$	130	$	82
Net income taxes paid to taxing authorities	1,039		299
Non-cash investing and financing activities:
Property, plant and equipment sold	4		4
Property, plant and equipment acquired	4		4

Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures

The consolidated statements of cash flows exclude changes to the consolidated balance sheets that did not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditures:

	Six Months Ended   June 30,
(In millions)	2015			2014
Additions to property, plant and equipment per consolidated statements of cash flows	$	764		$	569
Non-cash additions to property, plant and equipment	4			4
Asset retirement expenditures	—			1
Decrease in capital accruals	(20		)	(31		)
Total capital expenditures before acquisitions	$	748		$	543
Acquisitions	—			27
Total capital expenditures	$	748		$	570

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Commitments and Contingencies (Detail) - USD ($)
$ in Millions

6 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Loss Contingencies [Line Items]

Accrued liabilities for remediation

$ 172

$ 185

Receivables for recoverable costs

66

$ 67

Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees

1,700

Galveston Bay Refinery and Related Assets

Loss Contingencies [Line Items]

Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees

331

North Dakota Pipeline

Loss Contingencies [Line Items]

Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees

659

Illinois Extension Pipeline Company LLC

Loss Contingencies [Line Items]

Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees

116

Indemnification Agreement | Marathon Oil Companies

Loss Contingencies [Line Items]

Guarantee obligation current carrying value

2

Other Guarantees | Equity method investees

Loss Contingencies [Line Items]

Maximum potential undiscounted payments

82

Guarantee obligations maximum exposure per event

$ 50

Guarantee of Indebtedness of Others | Financial Guarantee | LOOP and LOCAP LLC

Loss Contingencies [Line Items]

Line of credit facility, expiration date

Dec. 31, 2037

Maximum potential undiscounted payments

$ 172

Master Shelf Agreement | Financial Guarantee | Centennial

Loss Contingencies [Line Items]

Line of credit facility, expiration date

Dec. 31, 2024

Maximum potential undiscounted payments

$ 36

Pending Litigation

Loss Contingencies [Line Items]

Loss contingency, inestimable loss

For matters for which we have not recorded an accrued liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings and discovery.

Pending Litigation | Emergency Pricing And Consumer Protection Laws

Loss Contingencies [Line Items]

Alleged amount overcharged from customers

$ 89

Loss contingency, period of occurrence

during September and October 2005

Plaintiff

Commonwealth of Kentucky

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Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 30	$ 13
Preferred stock:
Shares issued	0	0
Shares outstanding	0	0
Par value	$ 0.01
Shares authorized	30,000,000
Common stock:
Shares issued	728,000,000	726,000,000
Par value	$ 0.01
Shares authorized	1,000,000,000
Treasury stock	(191,000,000)	(179,000,000)

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Stock-Based Compensation Plans - Summary of Restricted Stock Award Activity (Detail) - 6 months ended Jun. 30, 2015 - $ / shares	Total
Restricted Stock
Number of Shares
Outstanding, beginning balance	1,030,146
Granted	505,698
RS’s Vested/RSU’s Issued	(516,406)
Forfeited	(34,396)
Outstanding, ending balance	985,042
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 38.62
Granted (in USD per share)	50.86
RS's Vested/RSU's Issued (in USD per share)	34.12
Forfeited (in USD per share)	39.22
Outstanding, ending balance (in USD per share)	$ 47.24
Restricted Stock Units
Number of Shares
Outstanding, beginning balance	822,186
Granted	23,831
RS’s Vested/RSU’s Issued	(944)
Forfeited	(850)
Outstanding, ending balance	844,223
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 18.65
Granted (in USD per share)	48.65
RS's Vested/RSU's Issued (in USD per share)	34.26
Forfeited (in USD per share)	44.77
Outstanding, ending balance (in USD per share)	$ 19.45

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Related Party Transactions - Purchases from Related Parties (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Related Party Transaction [Line Items]
Purchases from related parties	$ 82	$ 130	$ 158	$ 289
Centennial
Related Party Transaction [Line Items]
Purchases from related parties	0	(2)	0	7
Explorer
Related Party Transaction [Line Items]
Purchases from related parties	7	9	14	22
LOCAP
Related Party Transaction [Line Items]
Purchases from related parties	6	5	11	10
LOOP
Related Party Transaction [Line Items]
Purchases from related parties	13	12	26	65
TAAE
Related Party Transaction [Line Items]
Purchases from related parties	15	26	28	42
TACE
Related Party Transaction [Line Items]
Purchases from related parties	15	30	31	57
TAME
Related Party Transaction [Line Items]
Purchases from related parties	23	48	43	82
Other equity method investees
Related Party Transaction [Line Items]
Purchases from related parties	$ 3	$ 2	$ 5	$ 4

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Supplementary Statistics - Operating Statistics (Detail) bbl / d in Thousands, gal in Millions, $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015 USD ($) bbl / d Store $ / bbl $ / gal gal		Jun. 30, 2014 USD ($) bbl / d Store $ / bbl $ / gal gal		Jun. 30, 2015 USD ($) bbl / d Store $ / bbl $ / gal gal		Jun. 30, 2014 USD ($) bbl / d Store $ / bbl $ / gal gal
Operating Statistics [Line Items ]
MPC Consolidated Refined Product Sales Volumes (thousands of barrels per day)	[2]	2,341	[1]	2,154		2,294	[1]	2,059
Refining & Marketing
Refining & Marketing Operating Statistics
Refining & Marketing refined product sales volume (thousands of barrels per day)		2,329	[3]	2,145	[3]	2,281		2,048
Refining & Marketing gross margin (dollars per barrel) | $ / bbl	[4]	14.84		16.02		15.47		15.28
Crude oil capacity utilization percent	[5]	103.00%		98.00%		100.00%		91.00%
Refinery throughputs (thousands of barrels per day)	[6]	1,951		1,832		1,902		1,741
Sour crude oil throughput percent		55.00%		54.00%		55.00%		52.00%
WTI-priced crude oil throughput percent		19.00%		17.00%		20.00%		19.00%
Refined product yields (thousands of barrels per day)	[6]	1,982		1,865		1,930		1,772
Inter-refinery transfers		46		43		41		51
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	0.66		0.94		0.73		1.98
Depreciation and amortization | $ / bbl	[7]	1.33		1.39		1.38		1.47
Other manufacturing | $ / bbl	[7],[8]	3.94		4.77		4.08		5.32
Total | $ / bbl	[7]	5.93		7.10		6.19		8.77
Refining & Marketing | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[6]	1,789		1,674		1,731		1,563
Refining & Marketing | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[6]	162		158		171		178
Refining & Marketing | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	896		852		904		844
Refining & Marketing | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	631		610		592		562
Refining & Marketing | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	38		37		37		36
Refining & Marketing | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	331		288		315		255
Refining & Marketing | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	28		27		29		28
Refining & Marketing | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	58		51		53		47
Refining & Marketing | Gulf Coast:
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	1,265		1,187		1,238		1,129
Sour crude oil throughput percent		67.00%		67.00%		68.00%		64.00%
WTI-priced crude oil throughput percent		7.00%		2.00%		6.00%		3.00%
Refined product yields (thousands of barrels per day)	[9]	1,291		1,214		1,259		1,155
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	0.51		0.57		0.65		2.11
Depreciation and amortization | $ / bbl	[7]	1.06		1.13		1.10		1.19
Other manufacturing | $ / bbl	[7],[8]	3.75		4.77		3.87		5.28
Total | $ / bbl	[7]	5.32		6.47		5.62		8.58
Refining & Marketing | Gulf Coast: | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	1,093		1,031		1,062		946
Refining & Marketing | Gulf Coast: | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	172		156		176		183
Refining & Marketing | Gulf Coast: | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	511		500		517		494
Refining & Marketing | Gulf Coast: | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	408		390		375		355
Refining & Marketing | Gulf Coast: | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	27		25		26		23
Refining & Marketing | Gulf Coast: | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	320		270		314		258
Refining & Marketing | Gulf Coast: | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	11		16		13		15
Refining & Marketing | Gulf Coast: | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	14		13		14		10
Refining & Marketing | Midwest:
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	732		688		705		663
Sour crude oil throughput percent		36.00%		34.00%		35.00%		34.00%
WTI-priced crude oil throughput percent		39.00%		40.00%		41.00%		43.00%
Refined product yields (thousands of barrels per day)	[9]	737		694		712		668
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	0.89		1.53		0.82		1.62
Depreciation and amortization | $ / bbl	[7]	1.72		1.75		1.78		1.83
Other manufacturing | $ / bbl	[7],[8]	4.00		4.47		4.24		4.97
Total | $ / bbl	[7]	6.61		7.75		6.84		8.42
Refining & Marketing | Midwest: | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	696		643		669		617
Refining & Marketing | Midwest: | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	36		45		36		46
Refining & Marketing | Midwest: | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	385		352		387		350
Refining & Marketing | Midwest: | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	223		220		217		207
Refining & Marketing | Midwest: | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	13		13		13		14
Refining & Marketing | Midwest: | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	54		60		39		47
Refining & Marketing | Midwest: | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	18		11		17		13
Refining & Marketing | Midwest: | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	44		38		39		37
Speedway
Speedway Operating Statistics(b)
Convenience stores at period-end | Store		2,755	[1]	1,492		2,755	[1]	1,492
Gasoline and distillate sales (millions of gallons) | gal		1,514	[1]	806		2,946	[1]	1,579
Gasoline and distillate gross margin (dollars per gallon) | $ / gal		0.1351	[1],[10]	0.1282	[11]	0.1652	[1],[10]	0.1220	[10]
Merchandise sales (in millions) | $		$ 1,264	[1]	$ 830		$ 2,375	[1]	$ 1,552
Merchandise gross margin (in millions) | $		$ 359	[1]	$ 224		$ 670	[1]	$ 416
Merchandise margin percent		28.50%	[1]	27.10%		28.20%	[1]	26.80%
Same store gasoline sales volume (period over period) percentage		(0.20%)	[1],[12]	(1.50%)	[12]	(0.70%)	[1]	(1.10%)
Merchandise sales excluding cigarettes (period over period) percentage	[11]	4.60%	[1],[12]	4.60%	[12]	5.40%	[1]	4.90%
Pipeline Transportation
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day)	[13]	2,326		2,165		2,217		2,078
Pipeline Transportation | Crude oil pipelines
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day)	[13]	1,385		1,294		1,304		1,233
Pipeline Transportation | Refined products pipelines
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day)	[13]	941		871		913		845

[1] Includes the impact of Hess’ Retail Operations and Related Assets beginning on the September 30, 2014 acquisition date.

[2] Total average daily volumes of refined product sales to wholesale, branded and retail (Speedway segment) customers.

[3] Includes intersegment sales.

[4] Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.

[5] Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities.

[6] Excludes inter-refinery volumes of 46 mbpd and 43 mbpd for the three months ended June 30, 2015 and 2014, respectively, and 41 mbpd and 51 mbpd for the six months ended June 30, 2015 and 2014.

[7] Per barrel of total refinery throughputs.

[8] Includes utilities, labor, routine maintenance and other operating costs.

[9] Includes inter-refinery transfer volumes.

[10] The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.

[11] Excludes cigarettes.

[12] Same store comparison includes only locations owned at least 13 months

[13] On owned common-carrier pipelines, excluding equity method investments.

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Related Party Transactions (Tables)

6 Months Ended

Jun. 30, 2015

Related Party Transactions [Abstract]

Purchases From Related Parties

Purchases from related parties were as follows:

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015		2014			2015		2014
Centennial	$	—	$	(2	)	$	—	$	7
Explorer	7		9			14		22
LOCAP	6		5			11		10
LOOP	13		12			26		65
TAAE	15		26			28		42
TACE	15		30			31		57
TAME	23		48			43		82
Other equity method investees	3		2			5		4
Total	$	82	$	130		$	158	$	289

Receivables From Related Parties

Receivables from related parties, which are included in receivables, less allowance for doubtful accounts on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Centennial	$	1	$	2
Explorer	—		2
TAME	—		3
Total	$	1	$	7

Payables To Related Parties

Payables to related parties, which are included in accounts payable on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Explorer	$	4	$	3
LOCAP	2		2
LOOP	5		4
TAAE	1		2
TACE	2		2
TAME	3		5
Total	$	17	$	18

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Equity - Share Repurchases (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended		42 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015
Equity [Abstract]
Number of shares repurchased	8	10	12	26	191
Cash paid for shares repurchased	$ 408	$ 459	$ 617	$ 1,148	$ 6,890
Effective average cost per delivered share	$ 50.97	$ 44.07	$ 49.75	$ 43.91	$ 36.12

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Property, Plant and Equipment

6 Months Ended

Jun. 30, 2015

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

(In millions)	June 30, 2015		December 31, 2014
Refining & Marketing	$	18,434	$	18,001
Speedway	4,762		4,639
Pipeline Transportation	2,132		2,044
Corporate and Other	679		618
Total	26,007		25,302
Less accumulated depreciation	9,724		9,041
Property, plant and equipment, net	$	16,283	$	16,261

Included in construction in progress at June 30, 2015 is $136 million of costs associated with a residual fuel hydrocracker project at our Garyville refinery, which is intended to increase margins by upgrading residual fuel to ultra-low sulfur diesel and gas oil. We are deferring a final investment decision on this project as we further evaluate the implications of current market conditions on the project. If a decision is made to not pursue this project, there could be a future impairment of the costs incurred for the project.

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Income per Common Share (Tables)

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

Summary of Earnings Per Common Share

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Basic earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – basic	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Basic earnings per share	$	1.52	$	1.49	$	3.16	$	1.81
Diluted earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – diluted	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Effect of dilutive securities	3		4		4		4
Weighted average common shares, including dilutive effect	544		578		547		584
Diluted earnings per share	$	1.51	$	1.48	$	3.14	$	1.80

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

The following table summarizes the shares that were anti-dilutive, and therefore, were excluded from the diluted share calculation.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions)	2015	2014	2015	2014
Shares issued under stock-based compensation plans	1	1	1	1

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Supplementary Statistics - Supplementary Statistics (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Supplementary Statistics [Line Items]
Income from operations		$ 1,335		$ 1,369		$ 2,805	$ 1,730
Capital expenditures and investments	[1],[2]	513		363		897	734
Operating Segments
Supplementary Statistics [Line Items]
Income from operations	[3]	1,412		1,435		2,963	1,927
Capital expenditures and investments	[4]	464		343		819	683
Operating Segments | Refining & Marketing
Supplementary Statistics [Line Items]
Income from operations		1,206		1,260		2,522	1,622
Capital expenditures and investments		207		235		436	413
Operating Segments | Speedway
Supplementary Statistics [Line Items]
Income from operations		127		94		295	152
Capital expenditures and investments		100		44		145	76
Operating Segments | Pipeline Transportation
Supplementary Statistics [Line Items]
Income from operations	[3]	79		81		146	153
Capital expenditures and investments		157		64		238	194
Corporate and Other
Supplementary Statistics [Line Items]
Income from operations	[5],[6]	(76)		(61)		(156)	(128)
Capital expenditures and investments		49	[2]	20	[2]	78	51
Capitalized interest		8		7		16	13
Segment Reconciling Items
Supplementary Statistics [Line Items]
Pension settlement expenses	[7]	$ (1)		$ (5)		$ (2)	$ (69)

[1] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

[2] Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

[3] Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

[4] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

[5] Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets.

[6] Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

[7] See Note 19.

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Derivatives

6 Months Ended

Jun. 30, 2015

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives

Derivatives

For further information regarding the fair value measurement of derivative instruments, including any effect of master netting agreements or collateral, see Note 14. We do not designate any of our commodity derivative instruments as hedges for accounting purposes.

Derivatives that are not designated as accounting hedges may include commodity derivatives used to hedge price risk on (1) inventories, (2) fixed price sales of refined products, (3) the acquisition of foreign-sourced crude oil and (4) the acquisition of ethanol for blending with refined products.

The following table presents the gross fair values of derivative instruments, excluding cash collateral, and where they appear on the consolidated balance sheets as of June 30, 2015 and December 31, 2014:

	June 30, 2015
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	61	$	55	Other current assets
	December 31, 2014
(In millions)	Asset		Liability		Balance Sheet Location
Commodity derivatives	$	317	$	180	Other current assets

The table below summarizes open commodity derivative contracts as of June 30, 2015.

	Position	Total Barrels (In thousands)
Crude oil(a)
Exchange-traded	Long	12,403
Exchange-traded	Short	(24,938	)
Refined Products(b)
Exchange-traded	Long	4,004
Exchange-traded	Short	(2,439	)

^(a)  96.5 percent of these contracts expire in the third quarter of 2015.

^(b)  100 percent of these contracts expire in the third quarter of 2015.

The following table summarizes the effect of all commodity derivative instruments in our consolidated statements of income:

	Gain (Loss)						Gain (Loss)
(In millions)	Three Months Ended June 30,						Six Months Ended June 30,
Income Statement Location	2015			2014			2015			2014
Sales and other operating revenues	$	(3	)	$	(2	)	$	11		$	8
Cost of revenues	(70		)	(114		)	(25		)	(175		)
Total	$	(73	)	$	(116	)	$	(14	)	$	(167	)

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Segment Information - Reconciliation Of Segment Income From Operations To Income Before Income Taxes (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations		$ 1,335	$ 1,369	$ 2,805	$ 1,730
Net interest and other financial income (costs)		64	48	145	94
Income before income taxes		1,271	1,321	2,660	1,636
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations	[1]	1,412	1,435	2,963	1,927
Corporate and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations	[2],[3]	(76)	(61)	(156)	(128)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pension settlement expenses	[4]	$ (1)	$ (5)	$ (2)	$ (69)

[1] Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

[2] Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets.

[3] Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

[4] See Note 19.

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Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net income	$ 1,742	$ 1,071
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	725	645
Pension and other postretirement benefits, net	57	109
Deferred income taxes	(12)	(91)
Net gain on disposal of assets	(4)	(12)
Equity method investments, net	14	(44)
Changes in the fair value of derivative instruments	18	(2)
Changes in:
Current receivables	179	(161)
Inventories	102	(923)
Current accounts payable and accrued liabilities	(591)	994
All other, net	(46)	58
Net cash provided by operating activities	2,184	1,644
Investing activities:
Additions to property, plant and equipment	(764)	(569)
Acquisitions	0	(42)
Disposal of assets	12	17
Investments – acquisitions, loans and contributions	(149)	(164)
Investments - redemptions, repayments and return of capital	4	3
All other, net	41	74
Net cash used in investing activities	(856)	(681)
Financing activities:
Long-term debt – borrowings	528	270
Long-term debt – repayments	(427)	(26)
Debt issuance costs	(4)	0
Issuance of common stock	26	17
Common stock repurchased	(617)	(1,148)
Dividends paid	(272)	(245)
Distributions to noncontrolling interests	(18)	(12)
Contingent consideration payment	(175)	0
All other, net	18	14
Net cash used in financing activities	(941)	(1,130)
Net increase (decrease) in cash and cash equivalents	387	(167)
Cash and cash equivalents at beginning of period	1,494	2,292
Cash and cash equivalents at end of period	$ 1,881	$ 2,125

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Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 839	$ 864	$ 1,742	$ 1,071
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $7, ($3), $12 and $1	12	(5)	20	2
Prior service costs, net of tax of ($4), ($4), ($9) and ($9)	(8)	(8)	(16)	(16)
Other comprehensive income (loss)	4	(13)	4	(14)
Comprehensive income	843	851	1,746	1,057
Less comprehensive income attributable to noncontrolling interests	13	9	25	17
Comprehensive income attributable to MPC	$ 830	$ 842	$ 1,721	$ 1,040

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Equity

6 Months Ended

Jun. 30, 2015

Equity [Abstract]

Equity

Equity

On April 29, 2015, our board of directors approved a two-for-one stock split in the form of a stock dividend, which was distributed on June 10, 2015 to shareholders of record at the close of business on May 20, 2015. The total number of authorized shares of common stock and common stock par value per share remain unchanged. All historical share and per share data included in this report have been retroactively restated on a post-split basis.

Since January 1, 2012, we have repurchased a total of $6.89 billion of our common stock, leaving $1.11 billion available for repurchases as of June 30, 2015. We have acquired 191 million shares at an average cost per share of $36.12 under these authorizations. On July 29, 2015, our board of directors approved an additional $2.0 billion share repurchase authorization expiring in July 2017, bringing the total share repurchase authorizations to $10.0 billion.

We may utilize various methods to effect the repurchases, which could include open market repurchases, negotiated block transactions, accelerated share repurchases or open market solicitations for shares, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be discontinued at any time.

Total share repurchases were as follows for the three and six months ended June 30, 2015 and 2014:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Number of shares repurchased	8		10		12		26
Cash paid for shares repurchased	$	408	$	459	$	617	$	1,148
Effective average cost per delivered share	$	50.97	$	44.07	$	49.75	$	43.91

At June 30, 2015, we had agreements to acquire 173,532 common shares for $9 million, which were settled in early July 2015.

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Stock-Based Compensation Plans - Narrative (Detail)	6 Months Ended
	Jun. 30, 2015 $ / shares
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value (in USD per share)	$ 13.45
Performance Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in USD per share)	$ 0.95

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Defined Benefit Pension and Other Postretirement Plans - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Employer contributions			$ 0
Pension settlement expenses	$ 1	$ 5	2	$ 69
Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Benefits paid			6
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefits paid			12
Pension settlement expenses	$ 0	$ 0	$ 0	$ 0

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Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q2
Trading Symbol	MPC
Entity Registrant Name	Marathon Petroleum Corp
Entity Central Index Key	0001510295
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		536,156,786

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Segment Information

6 Months Ended

Jun. 30, 2015

Segment Reporting [Abstract]

Segment Information

Segment Information

We have three reportable segments: Refining & Marketing; Speedway; and Pipeline Transportation. Each of these segments is organized and managed based upon the nature of the products and services it offers.

• Refining & Marketing – refines crude oil and other feedstocks at our refineries in the Gulf Coast and Midwest regions of the United States, purchases ethanol and refined products for resale and distributes refined products through various means, including barges, terminals and trucks that we own or operate. We sell refined products to wholesale marketing customers domestically and internationally, to buyers on the spot market, to our Speedway segment and to independent entrepreneurs who operate Marathon^® retail outlets.

• Speedway – sells transportation fuels and convenience merchandise in retail markets in the Midwest, East Coast and Southeast regions of the United States.

• Pipeline Transportation – transports crude oil and other feedstocks to our refineries and other locations, delivers refined products to wholesale and retail market areas. This segment includes the aggregated operations of MPLX.

On September 30, 2014, we acquired Hess’ Retail Operations and Related Assets, substantially all of which are part of the Speedway segment. Segment information for the periods prior to the acquisition do not include amounts for these operations. See Note 4.

Segment income represents income from operations attributable to the reportable segments. Corporate administrative expenses and costs related to certain non-operating assets are not allocated to the reportable segments. In addition, certain items that affect comparability (as determined by the chief operating decision maker) are not allocated to the reportable segments.

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2015
Revenues:
Customer	$	15,192	$	5,329	$	16	$	20,537
Intersegment(a)	3,425		2		148		3,575
Segment revenues	$	18,617	$	5,331	$	164	$	24,112
Segment income from operations(b)	$	1,206	$	127	$	79	$	1,412
Income from equity method investments	8		—		12		20
Depreciation and amortization(c)	268		62		19		349
Capital expenditures and investments(d)	207		100		157		464

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2014
Revenues:
Customer	$	22,917	$	3,908	$	19	$	26,844
Intersegment(a)	2,590		1		131		2,722
Segment revenues	$	25,507	$	3,909	$	150	$	29,566
Segment income from operations(b)	$	1,260	$	94	$	81	$	1,435
Income from equity method investments	35		—		22		57
Depreciation and amortization(c)	264		29		19		312
Capital expenditures and investments(d)	235		44		64		343

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2015
Revenues:
Customer	$	27,836	$	9,860	$	32	$	37,728
Intersegment(a)	6,158		2		282		6,442
Segment revenues	$	33,994	$	9,862	$	314	$	44,170
Segment income from operations(b)	$	2,522	$	295	$	146	$	2,963
Income from equity method investments	14		—		21		35
Depreciation and amortization(c)	535		125		39		699
Capital expenditures and investments(d)	436		145		238		819

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2014
Revenues:
Customer	$	42,727	$	7,366	$	36	$	50,129
Intersegment(a)	4,823		2		260		5,085
Segment revenues	$	47,550	$	7,368	$	296	$	55,214
Segment income from operations(b)	$	1,622	$	152	$	153	$	1,927
Income from equity method investments	59		—		33		92
Depreciation and amortization(c)	525		57		38		620
Capital expenditures and investments(d)	413		76		194		683

^(a)  Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below.

^(d)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

The following reconciles segment income from operations to income before income taxes as reported in the consolidated statements of income:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Segment income from operations	$	1,412		$	1,435		$	2,963		$	1,927
Items not allocated to segments:
Corporate and other unallocated items(a)(b)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses(c)	(1		)	(5		)	(2		)	(69		)
Net interest and other financial income (costs)	(64		)	(48		)	(145		)	(94		)
Income before income taxes	$	1,271		$	1,321		$	2,660		$	1,636

^(a)  Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  See Note 19.

The following reconciles segment capital expenditures and investments to total capital expenditures:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions)	2015		2014		2015		2014
Segment capital expenditures and investments	$	464	$	343	$	819	$	683
Less: Investments in equity method investees	107		41		149		164
Plus: Items not allocated to segments:
Capital expenditures not allocated to segments	41		13		62		38
Capitalized interest	8		7		16		13
Total capital expenditures(a)	$	406	$	322	$	748	$	570

^(a)  Capital expenditures include changes in capital accruals. See Note 17 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

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Fair Value Measurements - Financial Instruments at Fair Value, Excluding Derivative Financial Instruments and Contingent Consideration (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Fair Value
Financial assets:
Investments		$ 34	$ 26
Other		32	32
Total financial assets		66	58
Financial liabilities:
Long-term debt	[1]	6,537	6,571
Deferred credits and other liabilities		19	17
Total financial liabilities		6,556	6,588
Carrying Value
Financial assets:
Investments		2	2
Other		31	32
Total financial assets		33	34
Financial liabilities:
Long-term debt	[1]	6,376	6,265
Deferred credits and other liabilities		19	17
Total financial liabilities		$ 6,395	$ 6,282

[1] Excludes capital leases and debt issuance costs, however, includes amount classified as short-term debt.

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Defined Benefit Pension and Other Postretirement Plans - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Components of net periodic benefit cost:
Service cost	$ 28	$ 20	$ 51	$ 43
Interest cost	18	18	36	38
Expected return on plan assets	(24)	(26)	(50)	(54)
Amortization – prior service credit	(11)	(11)	(23)	(23)
Amortization – actuarial loss	13	13	26	26
Amortization - settlement loss	1	5	2	69
Net periodic benefit cost	25	19	42	99
Other Benefits
Components of net periodic benefit cost:
Service cost	7	6	15	13
Interest cost	8	9	16	17
Expected return on plan assets	0	0	0	0
Amortization – prior service credit	(1)	(1)	(2)	(2)
Amortization – actuarial loss	1	0	4	1
Amortization - settlement loss	0	0	0	0
Net periodic benefit cost	$ 15	$ 14	$ 33	$ 29

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Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Actuarial changes, tax	$ 7	$ (3)	$ 12	$ 1
Prior service costs, tax	$ (4)	$ (4)	$ (9)	$ (9)

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MPLX LP

6 Months Ended

Jun. 30, 2015

Noncontrolling Interest [Abstract]

MPLX LP

MPLX LP

MPLX is a publicly traded master limited partnership that was formed by us to own, operate, develop and acquire pipelines and other midstream assets related to the transportation and storage of crude oil, refined products and other hydrocarbon-based products.

As of June 30, 2015, we owned a 71.5 percent interest in MPLX, including the two percent general partner interest. We consolidate this entity for financial reporting purposes since we have a controlling financial interest, and we record a noncontrolling interest for the interest owned by the public. As of June 30, 2015, MPLX’s assets consisted of a 99.5 percent general partner interest in MPLX Pipe Line Holdings LP (“Pipe Line Holdings”), which owns a network of common carrier crude oil and product pipeline systems and associated storage assets in the Midwest and Gulf Coast regions of the United States. MPLX also owns a 100 percent interest in a butane cavern in Neal, West Virginia.

Sales and Contributions to MPLX

On March 1, 2014, we sold MPLX a 13 percent interest in Pipe Line Holdings for $310 million. MPLX financed this transaction with $40 million of cash on-hand and $270 million of borrowings on its bank revolving credit facility.

On December 1, 2014, we sold and contributed interests in Pipe Line Holdings totaling 30.5 percent to MPLX for $600 million in cash and 2.9 million MPLX common units valued at $200 million. MPLX financed the cash portion of this transaction with $600 million of borrowings on its bank revolving credit facility.

The sales and contribution of our interests in Pipe Line Holdings to MPLX resulted in a change in our ownership in Pipe Line Holdings, but not a change in control. We accounted for them as transactions between entities under common control and did not record a gain or loss.

Public Offerings

On December 8, 2014, MPLX completed a public offering of 3.5 million common units at a price to the public of $66.68 per common unit, for aggregate net proceeds of $221 million. MPLX used the net proceeds from this offering to repay borrowings under its bank revolving credit facility and for general partnership purposes. On December 10, 2014, we exercised our right to maintain our two percent general partner interest in MPLX by purchasing 130 thousand general partner units for $9 million.

On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of four percent unsecured senior notes due February 15, 2025 (the “MPLX Senior Notes”). See Note 16 for more information.

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Accounting Standards

6 Months Ended

Jun. 30, 2015

Accounting Changes and Error Corrections [Abstract]

Accounting Standards

Accounting Standards

Recently Adopted

In April 2015, the FASB issued an accounting standards update to simplify the presentation of debt issuance costs. The update requires that debt issue costs for term debt are to be presented on the balance sheet as a direct reduction of the term debt liability as opposed to a deferred charge within other noncurrent assets. The change is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Retrospective application is required and early adoption is permitted. Our adoption of this standard in the second quarter of 2015 did not have a material impact on our consolidated results of operations, financial position or cash flows.

In June 2014, the FASB issued an accounting standards update for the elimination of the concept of development stage entity (“DSE”) from U.S. GAAP and removes the related incremental reporting. The standards update eliminates the additional financial statement requirements specific to a DSE and was adopted in the first quarter of 2015. In addition, the portion of the standard to amend the consolidation model that eliminates the special provisions in the variable interest entity ("VIE") rules for assessing the sufficiency of the equity of a DSE is effective in the first quarter of 2016. Adoption of this standards update in the first quarter of 2015 and 2016 has not and is not expected to have an impact on our consolidated results of operations, financial position or cash flows.

In April 2014, the FASB issued an accounting standards update that redefines the criteria for determining discontinued operations and introduces new disclosures related to these disposals. The updated definition of a discontinued operation is the disposal of a component (or components) of an entity or the classification of a component (or components) of an entity as held for sale that represents a strategic shift for an entity and has (or will have) a major impact on an entity’s operations and financial results. The standard requires disclosure of additional financial information for discontinued operations and individually material components not qualifying for discontinued operation presentation, as well as information regarding an entity’s continuing involvement with the discontinued operation. The accounting standards update was effective prospectively for annual periods beginning on or after December 15, 2014, and interim periods within those years. Adoption of this standards update in the first quarter of 2015 did not impact our consolidated results of operations, financial position or cash flows.

Not Yet Adopted

In May 2015, the FASB issued an accounting standard update that eliminates the requirement to categorize in the fair value hierarchy investments that are measured at net asset value using the practical expedient. The standard is effective for fiscal years beginning after December 15, 2015 and interim periods within the fiscal year. Retrospective application is required and early adoption is permitted. While we expect adoption of this standard to affect our fair value hierarchy disclosures, we do not believe it will have an impact on our consolidated results of operations, financial position or cash flows.

In April 2015, the FASB issued an accounting standards update clarifying whether a customer should account for a cloud computing arrangement as an acquisition of a software license or as a service arrangement by providing characteristics that a cloud computing arrangement must have in order to be accounted for as a software license acquisition. The change is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Retrospective or prospective application is allowed and early adoption is permitted. Adoption of this standard is not expected to have a material impact on our consolidated results of operations, financial position or cash flows.

In February 2015, the FASB issued an accounting standards update making targeted changes to the current consolidation guidance. The new standard changes the considerations related to substantive rights, related parties, and decision making fees when applying the VIE consolidation model and eliminates certain guidance for limited partnerships and similar entities under the voting interest consolidation model. The update is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Early adoption is permitted. At this point, we have not determined the impact of the new standards update on our consolidated financial statements and related disclosures. 

In August 2014, the FASB issued an accounting standards update requiring management to assess an entity’s ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. Management will be required to assess if there is substantial doubt about an entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Disclosures will be required if conditions give rise to substantial doubt and the type of disclosure will be determined based on whether management’s plans will be able to alleviate the substantial doubt. The accounting standards update will be effective for the first annual period ending after December 15, 2016, and for annual periods and interim periods thereafter with early application permitted.

In May 2014, the FASB issued an accounting standards update for revenue recognition that is aligned with the International Accounting Standards Board’s revenue recognition standard. The guidance in the update states that revenue is recognized when a customer obtains control of a good or service. Recognition of the revenue will involve a multiple step approach including identifying the contract, identifying the separate performance obligations, determining the transaction price, allocating the price to the performance obligations and then recognizing the revenue as the obligations are satisfied. Additional disclosures will be required to provide adequate information to understand the nature, amount, timing and uncertainty of reported revenues and revenues expected to be recognized. The accounting standards update will be effective on a retrospective or modified retrospective basis for annual reporting periods beginning after December 15, 2017, and interim periods within those years, with early adoption permitted, no earlier than January 1, 2017. We are in the process of determining the impact of the new standard on our consolidated financial statements.

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Fair Value Measurements

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

Fair Values—Recurring

The following tables present assets and liabilities accounted for at fair value on a recurring basis as of June 30, 2015 and December 31, 2014 by fair value hierarchy level. We have elected to offset the fair value amounts recognized for multiple derivative contracts executed with the same counterparty, including any related cash collateral as shown below; however, fair value amounts by hierarchy level are presented on a gross basis in the following tables.

	June 30, 2015
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	61	$	—	$	—	$	(43	)	$	18	$	20
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	63	$	—	$	—	$	(43	)	$	20	$	20
Commodity derivative instruments, liabilities	$	55	$	—	$	—	$	(55	)	$	—	$	—
Contingent consideration, liability(c)	—		—		307		N/A			307		—
Total liabilities at fair value	$	55	$	—	$	307	$	(55	)	$	307	$	—

	December 31, 2014
	Fair Value Hierarchy
(In millions)	Level 1		Level 2		Level 3		Netting and Collateral(a)			Net Carrying Value on Balance Sheet(b)		Collateral Pledged Not Offset
Commodity derivative instruments, assets	$	317	$	—	$	—	$	(258	)	$	59	$	—
Other assets	2		—		—		N/A			2		—
Total assets at fair value	$	319	$	—	$	—	$	(258	)	$	61	$	—
Commodity derivative instruments, liabilities	$	180	$	—	$	—	$	(180	)	$	—	$	—
Contingent consideration, liability(c)	—		—		478		N/A			478		—
Total liabilities at fair value	$	180	$	—	$	478	$	(180	)	$	478	$	—

^(a)  Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of June 30, 2015, cash collateral of $12 million was netted with the mark-to-market derivative liabilities. As of December 31, 2014, $78 million was netted with mark-to-market derivative assets.

^(b)  We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.

^(c)  Includes $190 million and $174 million classified as current at June 30, 2015 and December 31, 2014, respectively.

Commodity derivatives in Level 1 are exchange-traded contracts for crude oil and refined products measured at fair value with a market approach using the close-of-day settlement prices for the market. Commodity derivatives are covered under master netting agreements with an unconditional right to offset. Collateral deposits in futures commission merchant accounts covered by master netting agreements related to Level 1 commodity derivatives are classified as Level 1 in the fair value hierarchy.

The contingent consideration represents the fair value as of June 30, 2015 and December 31, 2014 of the remaining amount we expect to pay to BP related to the earnout provision associated with our 2013 acquisition of BP’s refinery in Texas City, Texas and related logistics and marketing assets. We refer to these assets as the “Galveston Bay Refinery and Related Assets.” The fair value of the remaining contingent consideration was estimated using an income approach and is therefore a Level 3 liability. The amount of cash to be paid under the arrangement is based on both a market-based crack spread and refinery throughput volumes for the months during which the earnout applies, as well as established thresholds that cap the annual and total payment. The earnout payment cannot exceed $200 million per year for the first three years of the arrangement or $250 million per year for the last three years of the arrangement, with the total cumulative payment capped at $700 million over the six-year period commencing in 2014. Any excess or shortfall from the annual cap for a current year’s earnout calculation will not affect subsequent years’ calculations. The fair value calculation used significant unobservable inputs, including: (1) an estimate of monthly refinery throughput volumes; (2) a range of internal and external monthly crack spread forecasts from approximately $8 to $20 per barrel; and (3) a range of risk-adjusted discount rates from five percent to 10 percent. An increase or decrease in crack spread forecasts or refinery throughput volume expectations may result in a corresponding increase or decrease in the fair value. Increases to the fair value as a result of increasing forecasts for both of these unobservable inputs, however, are limited as the earnout payment is subject to annual caps. An increase or decrease in the discount rate may result in a decrease or increase to the fair value, respectively. The fair value of the contingent consideration is reassessed each quarter, with changes in fair value recorded in cost of revenues.

In June 2015, we paid BP $189 million for the second year’s contingent earnout. On the consolidated statements of cash flows for the six months ended June 30, 2015, $175 million of the contingent earnout payment is included as a financing activity with the remainder included as an operating activity. In the third quarter of 2014, we paid BP $180 million for the first year’s contingent earnout.

The following is a reconciliation of the beginning and ending balances recorded for liabilities classified as Level 3 in the fair value hierarchy.

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015			2014		2015			2014
Beginning balance	$	490		$	639	$	478		$	625
Contingent consideration payment	(189		)	—		(189		)	—
Unrealized and realized losses included in net income	6			8		18			22
Ending balance	$	307		$	647	$	307		$	647

We did not hold any Level 3 derivative instruments during the three and six months ended June 30, 2015 and 2014. See Note 15 for the income statement impacts of our derivative instruments.

Fair Values - Nonrecurring

The following table shows the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition.

	Six Months Ended June 30,
	2015				2014
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Other noncurrent assets	$	—	$	—	$	—	$	11

Based on the financial and operational status of a company in which we have an interest, we fully impaired our $11 million investment in that company during the second quarter of 2014. Our investment in this company was accounted for using the cost method and was included in our Refining & Marketing segment. The impairment is included in other income on the consolidated statements of income. The fair value of our investment in this cost company was measured using an income approach. This measurement is classified as Level 3.

Fair Values – Reported

The following table summarizes financial instruments on the basis of their nature, characteristics and risk at June 30, 2015 and December 31, 2014, excluding the derivative financial instruments and contingent consideration reported above.

	June 30, 2015				December 31, 2014
(In millions)	Fair Value		Carrying Value		Fair Value		Carrying Value
Financial assets:
Investments	$	34	$	2	$	26	$	2
Other	32		31		32		32
Total financial assets	$	66	$	33	$	58	$	34
Financial liabilities:
Long-term debt(a)	$	6,537	$	6,376	$	6,571	$	6,265
Deferred credits and other liabilities	19		19		17		17
Total financial liabilities	$	6,556	$	6,395	$	6,588	$	6,282

^(a)  Excludes capital leases and debt issuance costs, however, includes amount classified as short-term debt.

Our current assets and liabilities include financial instruments, the most significant of which are trade accounts receivable and payables. We believe the carrying values of our current assets and liabilities approximate fair value. Our fair value assessment incorporates a variety of considerations, including (1) the short-term duration of the instruments, (2) our investment-grade credit rating and (3) our historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk.

Fair values of our financial assets included in investments and other financial assets and of our financial liabilities included in deferred credits and other liabilities are measured primarily using an income approach and most inputs are internally generated, which results in a Level 3 classification. Estimated future cash flows are discounted using a rate deemed appropriate to obtain the fair value. Other financial assets primarily consist of environmental remediation receivables. Deferred credits and other liabilities primarily consist of insurance liabilities and environmental remediation liabilities.

Fair value of fixed-rate long-term debt is measured using a market approach, based upon the average of quotes from major financial institutions and a third-party service for our debt. Because these quotes cannot be independently verified to the market, they are considered Level 3 inputs. Fair value of variable-rate long-term debt approximates the carrying value.

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Other Items

6 Months Ended

Jun. 30, 2015

Other Income and Expenses [Abstract]

Other Items

Other Items

Net interest and other financial income (costs) was:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Interest income	$	2		$	1		$	3		$	3
Interest expense	(69		)	(49		)	(149		)	(98		)
Interest capitalized	8			7			16			13
Other financial costs	(5		)	(7		)	(15		)	(12		)
Net interest and other financial income (costs)	$	(64	)	$	(48	)	$	(145	)	$	(94	)

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Debt - Outstanding Borrowings (Detail) - USD ($) $ in Millions			6 Months Ended
		Feb. 12, 2015	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total			$ 6,760	$ 6,657
Unamortized debt issuance costs	[1]		(38)	(35)
Unamortized discount			(27)	(26)
Fair value adjustments	[2]		3	6
Amounts due within one year			(780)	(27)
Total long-term debt due after one year			5,918	6,575
Interest Rate Swap
Debt Instrument [Line Items]
Deferred gain on discontinuation of interest rate fair value hedge			20
Consolidated subsidiaries: | Capital Lease Obligations
Debt Instrument [Line Items]
Capital lease obligations			$ 360	372
Debt instrument maturity year, start			Jan. 01, 2015
Debt instrument maturity year, end			Dec. 31, 2028
3.500% senior notes due March 1, 2016 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 750	750
Debt instrument, maturity date			Mar. 01, 2016
Debt instrument, interest rate			3.50%
MPC Revolver | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross			$ 0	0
Line of credit facility, expiration date			Sep. 14, 2017
MPC Term Loan | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt, gross			$ 700	700
Line of credit facility, expiration date			Sep. 30, 2019
5.125% senior notes due March 1, 2021 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 1,000	1,000
Debt instrument, maturity date			Mar. 01, 2021
Debt instrument, interest rate			5.125%
3.625% senior notes due September 15, 2024 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 750	750
Debt instrument, maturity date			Sep. 15, 2024
Debt instrument, interest rate			3.625%
6.500% senior notes due March 1, 2041 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 1,250	1,250
Debt instrument, maturity date			Mar. 01, 2041
Debt instrument, interest rate			6.50%
4.750% senior notes due September 15, 2044 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 800	800
Debt instrument, maturity date			Sep. 15, 2044
Debt instrument, interest rate			4.75%
5.000% senior notes due September 15, 2054 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 400	400
Debt instrument, maturity date			Sep. 15, 2054
Debt instrument, interest rate			5.00%
MPLX Revolver | MPLX LP | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross			$ 0	385
MPLX Term Loan | MPLX LP | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt, gross			$ 250	250
Line of credit facility, expiration date			Dec. 20, 2019
4.000% senior notes due two thousand twenty five | MPLX LP | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 500	0
Debt instrument, maturity date		Feb. 15, 2025	Feb. 15, 2025
Debt instrument, interest rate		4.00%	4.00%
Trade Receivables Securitization | Consolidated subsidiaries: | Secured Debt
Debt Instrument [Line Items]
Long-term debt, gross			$ 0	$ 0
Line of credit facility, expiration date			Dec. 31, 2016

[1] We adopted the updated FASB debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented. We reclassified unamortized debt issuance costs related to term debt from other noncurrent assets to long-term debt.

[2] The $20 million gain on the termination of our interest rate swap agreements in 2012 is being amortized over the remaining life of the 3.50 percent senior notes.

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Related Party Transactions

6 Months Ended

Jun. 30, 2015

Related Party Transactions [Abstract]

Related Party Transactions

Related Party Transactions

Our related parties include:

• Centennial Pipeline LLC (“Centennial”), in which we have a 50 percent noncontrolling interest. Centennial owns a refined products pipeline and storage facility.

• Explorer, in which we have a 25 percent interest. Explorer owns and operates a refined products pipeline.

• LOCAP LLC (“LOCAP”), in which we have a 59 percent noncontrolling interest. LOCAP owns and operates a crude oil pipeline.

• LOOP LLC (“LOOP”), in which we have a 51 percent noncontrolling interest. LOOP owns and operates the only U.S. deepwater oil port.

• TAAE, in which we have a 43 percent noncontrolling interest, TACE, in which we have a 60 percent noncontrolling interest and TAME, in which we have a 67 percent direct and indirect noncontrolling interest. These companies each own and operate an ethanol production facility.

• Other equity method investees.

We believe that transactions with related parties were conducted on terms comparable to those with unaffiliated parties.

Sales to related parties, which are included in sales and other operating revenues (including consumer excise taxes) on the consolidated statements of income, were $2 million for both the three months ended June 30, 2015 and 2014 and $3 million and $4 million for the six months ended June 30, 2015 and 2014, respectively.

Purchases from related parties were as follows:

	Three Months Ended   June 30,					Six Months Ended   June 30,
(In millions)	2015		2014			2015		2014
Centennial	$	—	$	(2	)	$	—	$	7
Explorer	7		9			14		22
LOCAP	6		5			11		10
LOOP	13		12			26		65
TAAE	15		26			28		42
TACE	15		30			31		57
TAME	23		48			43		82
Other equity method investees	3		2			5		4
Total	$	82	$	130		$	158	$	289

Related party purchases from Centennial consist primarily of refinery feedstocks and refined product transportation costs. Related party purchases from Explorer consist primarily of refined product transportation costs. Related party purchases from LOCAP, LOOP and other equity method investees consist primarily of crude oil transportation costs and crude oil purchases. Related party purchases from TAAE, TACE and TAME consist of ethanol purchases.

Receivables from related parties, which are included in receivables, less allowance for doubtful accounts on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Centennial	$	1	$	2
Explorer	—		2
TAME	—		3
Total	$	1	$	7

Payables to related parties, which are included in accounts payable on the consolidated balance sheets, were as follows:

(In millions)	June 30, 2015		December 31, 2014
Explorer	$	4	$	3
LOCAP	2		2
LOOP	5		4
TAAE	1		2
TACE	2		2
TAME	3		5
Total	$	17	$	18

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Related Party Transactions - Receivables From Related Parties (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Current receivables from related parties	$ 1	$ 7
Centennial
Related Party Transaction [Line Items]
Current receivables from related parties	1	2
Explorer
Related Party Transaction [Line Items]
Current receivables from related parties	0	2
TAME
Related Party Transaction [Line Items]
Current receivables from related parties	$ 0	$ 3

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Acquisitions and Investments

6 Months Ended

Jun. 30, 2015

Business Combinations [Abstract]

Acquisitions and Investments

Acquisitions and Investments

Acquisition of Hess’ Retail Operations and Related Assets

On September 30, 2014, we acquired from Hess Corporation (“Hess”) all of Hess’ retail locations, transport operations and shipper history on various pipelines, including approximately 40,000 barrels per day on Colonial Pipeline for $2.82 billion. We refer to these assets as “Hess’ Retail Operations and Related Assets.” The transaction was funded with a combination of debt and available cash. The transaction provided for an adjustment for working capital, which was finalized during the first quarter of 2015, resulting in a $3 million reduction to our total consideration. This amount is consistent with the estimate we used in prior periods and therefore, the fair value of the assets acquired and liabilities assumed remain unchanged from year-end 2014.

The purchase price allocation resulted in the recognition of $629 million in goodwill by our Speedway segment. The goodwill primarily relates to the expected benefits of a significantly expanded retail platform that should enable growth in new markets, as well as the potential for higher merchandise sales by utilizing Speedway’s marketing approach at the acquired locations. We also expect strategic benefits from the financial and operational scale we expect to realize across our entire retail network. The goodwill is deductible for tax purposes.

The following unaudited pro forma financial information presents consolidated results assuming the acquisition of Hess’ Retail Operations and Related Assets occurred on January 1, 2013. The pro forma financial information does not give effect to potential synergies that could result from the acquisition and is not necessarily indicative of the results of future operations.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions, except per share data)	2014		2014
Sales and other operating revenues (including consumer excise taxes)	$	29,931	$	55,948
Net income attributable to MPC	869		1,051
Net income attributable to MPC per share – basic	$	1.51	$	1.81
Net income attributable to MPC per share – diluted	1.50		1.80

The pro forma information includes adjustments to align accounting policies, an adjustment to depreciation expense to reflect the fair value of property, plant and equipment, increased amortization expense related to identifiable intangible assets, additional interest expense related to financing the acquisition, as well as the related income tax effects.

Acquisition of Biodiesel Facility

On April 1, 2014, we purchased a biodiesel facility in Cincinnati, Ohio from Felda Iffco Sdn Bhd, Malaysia for $40 million. The plant currently produces biodiesel, glycerin and other by-products and has a capacity of approximately 60 million gallons per year.

Neither goodwill nor a gain from a bargain purchase was recognized in conjunction with the acquisition.

Assuming the acquisition had been made at the beginning of any period presented, the consolidated pro forma results would not be materially different from reported results.

Investments in Pipeline Companies

In July 2014, we exercised our option to acquire a 35 percent ownership interest in Enbridge Inc.’s Southern Access Extension pipeline (“SAX”) through our investment in Illinois Extension Pipeline Company, LLC (“Illinois Extension Pipeline”). During the six months ended June 30, 2015, we made contributions of $94 million to Illinois Extension Pipeline to fund our portion of the construction costs for the SAX project. We have contributed $214 million since project inception. We account for our ownership interest in Illinois Extension Pipeline as an equity method investment. See Note 21 for information on future contributions to Illinois Extension Pipeline.

In March 2014, we acquired from Chevron Raven Ridge Pipe Line Company an additional seven percent interest in Explorer Pipeline Company (“Explorer”) for $77 million, bringing our ownership interest to 25 percent. As a result of this increase in our ownership, we now account for our investment in Explorer using the equity method of accounting rather than the cost method. The cumulative impact of the change was applied as an adjustment to 2014 retained earnings.

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Variable Interest Entity

6 Months Ended

Jun. 30, 2015

Variable Interest Entity [Abstract]

Variable Interest Entity

Variable Interest Entity

As stated in Note 4, we have a 35 percent ownership interest in Illinois Extension Pipeline. Illinois Extension Pipeline Company LLC is considered a VIE because it is a development stage entity and the equity in the entity is not sufficient to fund the construction of the SAX pipeline. Our maximum exposure to loss due to this VIE at June 30, 2015 was $214 million, which equates to our contributions to-date to fund our portion of the construction costs for the project.

We are not the primary beneficiary of this VIE because we do not have the power to control the activities that significantly influence the economic performance of the entity and, therefore, do not consolidate the entity. The activities that most significantly impact the VIE’s economic performance are the actual construction costs and risks associated with the on-going construction. Through our vote, we have shared power to direct the construction activities, but do not have the sole ability to control the construction activities.

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Income per Common Share

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

Income per Common Share

Income per Common Share

We compute basic earnings per share by dividing net income attributable to MPC by the weighted average number of shares of common stock outstanding. The average number of shares of common stock and per share amounts have been retroactively restated to reflect the two-for-one stock split completed in June 2015. Diluted income per share assumes exercise of certain stock-based compensation awards, provided the effect is not anti-dilutive.

MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities. Due to the presence of participating securities, we have calculated our earnings per share using the two-class method.

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions, except per share data)	2015		2014		2015		2014
Basic earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – basic	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Basic earnings per share	$	1.52	$	1.49	$	3.16	$	1.81
Diluted earnings per share:
Allocation of earnings:
Net income attributable to MPC	$	826	$	855	$	1,717	$	1,054
Income allocated to participating securities	1		1		3		2
Income available to common stockholders – diluted	$	825	$	854	$	1,714	$	1,052
Weighted average common shares outstanding	541		574		543		580
Effect of dilutive securities	3		4		4		4
Weighted average common shares, including dilutive effect	544		578		547		584
Diluted earnings per share	$	1.51	$	1.48	$	3.14	$	1.80

The following table summarizes the shares that were anti-dilutive, and therefore, were excluded from the diluted share calculation.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions)	2015	2014	2015	2014
Shares issued under stock-based compensation plans	1	1	1	1

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Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended		42 Months Ended
	Jul. 29, 2015	Jul. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchase plan authorized amount			$ 8,000		$ 8,000		$ 8,000
Cash paid for shares repurchased			408	$ 459	617	$ 1,148	6,890
Stock repurchase plan remaining authorized amount			$ 1,110		$ 1,110		$ 1,110
Number of shares repurchased			8,000,000	10,000,000	12,000,000	26,000,000	191,000,000
Effective average cost per delivered share			$ 50.97	$ 44.07	$ 49.75	$ 43.91	$ 36.12
Scenario, Forecast
Equity, Class of Treasury Stock [Line Items]
Cash paid for shares repurchased		$ 9
Number of shares repurchased		173,532
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Stock repurchase plan authorized amount	$ 10,000
Share Repurchase Authorization July 2015 | Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Stock repurchase plan authorized amount	$ 2,000
Stock repurchase program expiration date	Jul. 31, 2017

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Debt MPLX Senior Notes (Details) - MPLX LP - Senior Notes - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Feb. 12, 2015
Debt Instrument [Line Items]
Proceeds from (repayments of) debt	$ 495
4.000% senior notes due two thousand twenty five
Debt Instrument [Line Items]
Debt instrument, face amount		$ 500

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Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015 Segment
Segment Reporting [Abstract]
Number of reportable segments	3

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Income Per Common Share - Anti-dilutive Shares (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock Based Compensation Expense [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issued under stock-based compensation plans	1	1	1	1

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Stock-Based Compensation Plans - Summary of Stock Option Award Activity (Detail) - 6 months ended Jun. 30, 2015 - Stock Options - $ / shares	Total
Number of Shares
Outstanding, beginning balance	9,502,876
Granted	1,094,676
Exercised	(1,492,710)
Forfeited, canceled or expired	(48,766)
Outstanding, ending balance	9,056,076
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share)	$ 22.74
Granted (in USD per share)	50.89
Exercised (in USD per share)	17.49
Forfeited, canceled or expired (in USD per share)	39.84
Outstanding, ending balance (in USD per share)	$ 26.91

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Acquisitions and Investments (Tables)

6 Months Ended

Jun. 30, 2015

Business Combinations [Abstract]

Business Acquisition, Pro Forma Information [Table Text Block]

The following unaudited pro forma financial information presents consolidated results assuming the acquisition of Hess’ Retail Operations and Related Assets occurred on January 1, 2013. The pro forma financial information does not give effect to potential synergies that could result from the acquisition and is not necessarily indicative of the results of future operations.

	Three Months Ended   June 30,		Six Months Ended   June 30,
(In millions, except per share data)	2014		2014
Sales and other operating revenues (including consumer excise taxes)	$	29,931	$	55,948
Net income attributable to MPC	869		1,051
Net income attributable to MPC per share – basic	$	1.51	$	1.81
Net income attributable to MPC per share – diluted	1.50		1.80

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MPLX LP (Sales and Contributions) (Details) - USD ($) shares in Millions, $ in Millions	Dec. 01, 2014	Mar. 01, 2014
MPLX LP | Limited Partner
Noncontrolling Interest [Line Items]
Equity interest issued or issuable, number of shares	2.9
Equity interest issued or issuable, value assigned	$ 200
MPLX LP | MPLX Revolver
Noncontrolling Interest [Line Items]
Cash paid for acquisition	$ 600	$ 270
MPLX LP | Cash and cash equivalents
Noncontrolling Interest [Line Items]
Cash paid for acquisition		$ 40
MPLX Pipe Line Holdings LP
Noncontrolling Interest [Line Items]
Additional interest sold	30.50%	13.00%
Proceeds from sale of ownership interest	$ 600	$ 310

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Inventories

6 Months Ended

Jun. 30, 2015

Inventory Disclosure [Abstract]

Inventories

Inventories

(In millions)	June 30, 2015		December 31, 2014
Crude oil and refinery feedstocks	$	2,147	$	2,219
Refined products	2,880		2,955
Materials and supplies	338		302
Merchandise	175		166
Total (at cost)	$	5,540	$	5,642

Inventories are carried at the lower of cost or market value. The cost of inventories of crude oil and refinery feedstocks, refined products and merchandise is determined primarily under the last-in, first-out (“LIFO”) method. During the six months ended June 30, 2015, we recorded LIFO liquidations caused by permanently decreased levels in refined products inventory volumes. Cost of revenues increased and income from operations decreased by approximately $30 million for the six months ended June 30, 2015 as a result of the LIFO liquidations. There were no liquidations of LIFO inventories for the six months ended June 30, 2014.

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Supplemental Cash Flow Information

6 Months Ended

Jun. 30, 2015

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

Supplemental Cash Flow Information

	Six Months Ended   June 30,
(In millions)	2015		2014
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$	130	$	82
Net income taxes paid to taxing authorities	1,039		299
Non-cash investing and financing activities:
Property, plant and equipment sold	4		4
Property, plant and equipment acquired	4		4

The consolidated statements of cash flows exclude changes to the consolidated balance sheets that did not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditures:

	Six Months Ended   June 30,
(In millions)	2015			2014
Additions to property, plant and equipment per consolidated statements of cash flows	$	764		$	569
Non-cash additions to property, plant and equipment	4			4
Asset retirement expenditures	—			1
Decrease in capital accruals	(20		)	(31		)
Total capital expenditures before acquisitions	$	748		$	543
Acquisitions	—			27
Total capital expenditures	$	748		$	570

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Stock-Based Compensation Plans - Summary of Performance Unit Awards (Detail) - 6 months ended Jun. 30, 2015 - Performance Unit Awards - $ / shares	Total
Number of Units
Outstanding, beginning balance	5,791,825
Granted	2,389,450
Settled	(2,035,833)
Outstanding, ending balance	6,145,442
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 0.88
Granted (in USD per share)	0.95
Settled (in USD per share)	0.85
Outstanding, ending balance (in USD per share)	$ 0.92

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Supplementary Statistics (Tables)

6 Months Ended

Jun. 30, 2015

Text Block [Abstract]

Supplementary Statistics

Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Income from Operations by segment
Refining & Marketing	$	1,206		$	1,260		$	2,522		$	1,622
Speedway	127			94			295			152
Pipeline Transportation(a)	79			81			146			153
Items not allocated to segments:
Corporate and other unallocated items(a)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses	(1		)	(5		)	(2		)	(69		)
Income from operations	$	1,335		$	1,369		$	2,805		$	1,730
Capital Expenditures and Investments(b)
Refining & Marketing	$	207		$	235		$	436		$	413
Speedway	100			44			145			76
Pipeline Transportation	157			64			238			194
Corporate and Other(c)	49			20			78			51
Total	$	513		$	363		$	897		$	734

^(a)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(b)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

^(c)  Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

Operating Statistics

Supplementary Statistics (Unaudited)

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2015		2014		2015		2014
MPC Consolidated Refined Product Sales Volumes (thousands of barrels per day)(a)(b)	2,341		2,154		2,294		2,059
Refining & Marketing Operating Statistics
Refining & Marketing refined product sales volume (thousands of barrels per day)(c)	2,329		2,145		2,281		2,048
Refining & Marketing gross margin (dollars per barrel)(d)	$	14.84	$	16.02	$	15.47	$	15.28
Crude oil capacity utilization percent(e)	103		98		100		91
Refinery throughputs (thousands of barrels per day):(f)
Crude oil refined	1,789		1,674		1,731		1,563
Other charge and blendstocks	162		158		171		178
Total	1,951		1,832		1,902		1,741
Sour crude oil throughput percent	55		54		55		52
WTI-priced crude oil throughput percent	19		17		20		19
Refined product yields (thousands of barrels per day):(f)
Gasoline	896		852		904		844
Distillates	631		610		592		562
Propane	38		37		37		36
Feedstocks and special products	331		288		315		255
Heavy fuel oil	28		27		29		28
Asphalt	58		51		53		47
Total	1,982		1,865		1,930		1,772
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.66	$	0.94	$	0.73	$	1.98
Depreciation and amortization	1.33		1.39		1.38		1.47
Other manufacturing(h)	3.94		4.77		4.08		5.32
Total	$	5.93	$	7.10	$	6.19	$	8.77
Refining & Marketing Operating Statistics By Region - Gulf Coast
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	1,093		1,031		1,062		946
Other charge and blendstocks	172		156		176		183
Total	1,265		1,187		1,238		1,129
Sour crude oil throughput percent	67		67		68		64
WTI-priced crude oil throughput percent	7		2		6		3
Refined product yields (thousands of barrels per day):(i)
Gasoline	511		500		517		494
Distillates	408		390		375		355
Propane	27		25		26		23
Feedstocks and special products	320		270		314		258
Heavy fuel oil	11		16		13		15
Asphalt	14		13		14		10
Total	1,291		1,214		1,259		1,155
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.51	$	0.57	$	0.65	$	2.11
Depreciation and amortization	1.06		1.13		1.10		1.19
Other manufacturing(h)	3.75		4.77		3.87		5.28
Total	$	5.32	$	6.47	$	5.62	$	8.58

Supplementary Statistics (Unaudited)
	Three Months Ended   June 30,						Six Months Ended   June 30,
	2015			2014			2015			2014
Refining & Marketing Operating Statistics By Region – Midwest
Refinery throughputs (thousands of barrels per day):(i)
Crude oil refined	696			643			669			617
Other charge and blendstocks	36			45			36			46
Total	732			688			705			663
Sour crude oil throughput percent	36			34			35			34
WTI-priced crude oil throughput percent	39			40			41			43
Refined product yields (thousands of barrels per day):(i)
Gasoline	385			352			387			350
Distillates	223			220			217			207
Propane	13			13			13			14
Feedstocks and special products	54			60			39			47
Heavy fuel oil	18			11			17			13
Asphalt	44			38			39			37
Total	737			694			712			668
Refinery direct operating costs (dollars per barrel):(g)
Planned turnaround and major maintenance	$	0.89		$	1.53		$	0.82		$	1.62
Depreciation and amortization	1.72			1.75			1.78			1.83
Other manufacturing(h)	4.00			4.47			4.24			4.97
Total	$	6.61		$	7.75		$	6.84		$	8.42
Speedway Operating Statistics(b)
Convenience stores at period-end	2,755			1,492
Gasoline and distillate sales (millions of gallons)	1,514			806			2,946			1,579
Gasoline and distillate gross margin (dollars per gallon)(j)	$	0.1351		$	0.1282		$	0.1652		$	0.1220
Merchandise sales (in millions)	$	1,264		$	830		$	2,375		$	1,552
Merchandise gross margin (in millions)	$	359		$	224		$	670		$	416
Merchandise gross margin percent	28.5		%	27.1		%	28.2		%	26.8		%
Same store gasoline sales volume (period over period)(k)	(0.2		%)	(1.5		%)	(0.7		%)	(1.1		%)
Same store merchandise sales (period over period)(k)(l)	4.6		%	4.6		%	5.4		%	4.9		%
Pipeline Transportation Operating Statistics
Pipeline throughputs (thousands of barrels per day):(m)
Crude oil pipelines	1,385			1,294			1,304			1,233
Refined products pipelines	941			871			913			845
Total	2,326			2,165			2,217			2,078

^(a)  Total average daily volumes of refined product sales to wholesale, branded and retail (Speedway segment) customers.

^(b)  Includes the impact of Hess’ Retail Operations and Related Assets beginning on the September 30, 2014 acquisition date.

^(c)  Includes intersegment sales.

^(d)  Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.

^(e)  Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities.

^(f)  Excludes inter-refinery volumes of 46 mbpd and 43 mbpd for the three months ended June 30, 2015 and 2014, respectively, and 41 mbpd and 51 mbpd for the six months ended June 30, 2015 and 2014.

^(g)  Per barrel of total refinery throughputs.

^(h)  Includes utilities, labor, routine maintenance and other operating costs.

⁽ⁱ⁾  Includes inter-refinery transfer volumes.

^(j)  The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.

^(k)  Same store comparison includes only locations owned at least 13 months, and therefore excludes locations acquired from Hess.

^(l)  Excludes cigarettes.

^(m)   On owned common-carrier pipelines, excluding equity method investments.

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Property, Plant and Equipment (Tables)

6 Months Ended

Jun. 30, 2015

Property, Plant and Equipment [Abstract]

Summary Of Property, Plant And Equipment

(In millions)	June 30, 2015		December 31, 2014
Refining & Marketing	$	18,434	$	18,001
Speedway	4,762		4,639
Pipeline Transportation	2,132		2,044
Corporate and Other	679		618
Total	26,007		25,302
Less accumulated depreciation	9,724		9,041
Property, plant and equipment, net	$	16,283	$	16,261

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Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 1,881	$ 1,494
Receivables, less allowance for doubtful accounts of $30 and $13	3,876	4,058
Inventories	5,540	5,642
Other current assets	134	145
Total current assets	11,431	11,339
Equity method investments	994	865
Property, plant and equipment, net	16,283	16,261
Goodwill	1,566	1,566
Other noncurrent assets	379	394
Total assets	30,653	30,425
Current liabilities:
Accounts payable	6,225	6,661
Payroll and benefits payable	369	427
Consumer excise taxes payable	469	463
Accrued taxes	517	647
Long-term debt due within one year	780	27
Other current liabilities	365	354
Total current liabilities	8,725	8,579
Long-term debt	5,918	6,575
Deferred income taxes	2,011	2,014
Defined benefit postretirement plan obligations	1,143	1,099
Deferred credits and other liabilities	566	768
Total liabilities	$ 18,363	$ 19,035
Commitments and contingencies (see Note 21)
MPC stockholders’ equity:
Preferred stock, no shares issued and outstanding (par value $0.01 per share, 30 million shares authorized)	$ 0	$ 0
Common stock:
Issued – 728 million and 726 million shares (par value $0.01 per share, 1 billion shares authorized)	7	7
Held in treasury, at cost – 191 million and 179 million shares	(6,926)	(6,299)
Additional paid-in capital	9,912	9,841
Retained earnings	8,959	7,515
Accumulated other comprehensive loss	(309)	(313)
Total MPC stockholders’ equity	11,643	10,751
Noncontrolling interests	647	639
Total equity	12,290	11,390
Total liabilities and equity	$ 30,653	$ 30,425

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Supplemental Cash Flow Information - Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]
Additions to property, plant and equipment per consolidated statements of cash flows				$ 764	$ 569
Non-cash additions to property, plant and equipment				4	4
Asset retirement expenditures				0	1
Decrease in capital accruals				(20)	(31)
Total capital expenditures before acquisitions				748	543
Acquisitions				0	27
Total capital expenditures	[1]	$ 406	$ 322	$ 748	$ 570

[1] Capital expenditures include changes in capital accruals. See Note 17 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

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Description of the Business and Basis of Presentation

6 Months Ended

Jun. 30, 2015

Accounting Policies [Abstract]

Description of the Business and Basis of Presentation

Description of the Business and Basis of Presentation

Description of the Business—Our business consists of refining and marketing, retail marketing and pipeline transportation operations conducted primarily in the Midwest, Gulf Coast, East Coast and Southeast regions of the United States, through subsidiaries, including Marathon Petroleum Company LP, Speedway LLC and its subsidiaries (“Speedway”) and MPLX LP and its subsidiaries (“MPLX”).

See Note 9 for additional information about our operations.

Basis of Presentation—All significant intercompany transactions and accounts have been eliminated.

These interim consolidated financial statements are unaudited; however, in the opinion of our management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal, recurring nature unless otherwise disclosed. These interim consolidated financial statements, including the notes, have been prepared in accordance with the rules of the Securities and Exchange Commission applicable to interim period financial statements and do not include all of the information and disclosures required by United States generally accepted accounting principles (“U.S. GAAP”) for complete financial statements.

These interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2014. The results of operations for the three and six months ended June 30, 2015 are not necessarily indicative of the results to be expected for the full year.

We completed a two-for-one stock split in June 2015. All historical share and per share data included in this report has been retroactively restated on a post-split basis. Additionally, we adopted the updated Financial Accounting Standards Board (“FASB”) debt issuance cost standard as of June 30, 2015 and applied the changes retrospectively to the prior period presented.

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Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Centennial
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	50.00%		50.00%
Explorer
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	25.00%		25.00%
LOCAP
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	59.00%		59.00%
LOOP
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	51.00%		51.00%
TAAE
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	43.00%		43.00%
TACE
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	60.00%		60.00%
TAME
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	67.00%		67.00%
Other equity method investees
Related Party Transaction [Line Items]
Sales to related parties	$ 2	$ 2	$ 3	$ 4

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Derivatives - Open Commodity Derivative Contracts (Detail) - Jun. 30, 2015 - bbl bbl in Thousands		Total
Derivative [Line Items]
Derivative contract expiration date		Sep. 30, 2015
Crude Oil Exchange-Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period		96.50%
Crude Oil Exchange-Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	[1]	12,403
Crude Oil Exchange-Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	[1]	24,938
Refined Products Exchange-Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period		100.00%
Refined Products Exchange-Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	[2]	4,004
Refined Products Exchange-Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	[2]	2,439

[1] 96.5 percent of these contracts expire in the third quarter of 2015.

[2] 100 percent of these contracts expire in the third quarter of 2015.

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Segment Information - Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures [Line Items]
Capital expenditures and investments	[1],[2]	$ 513		$ 363		$ 897	$ 734
Plus: Items not allocated to segments:
Capital expenditures	[3]	406		322		748	570
Operating Segments
Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures [Line Items]
Capital expenditures and investments	[4]	464		343		819	683
Less: Investments in equity method investees		(107)		(41)		(149)	(164)
Corporate and Other
Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures [Line Items]
Capital expenditures and investments		49	[2]	20	[2]	78	51
Plus: Items not allocated to segments:
Capital expenditures not allocated to segments		41		13		62	38
Capitalized interest		$ 8		$ 7		$ 16	$ 13

[1] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

[2] Includes capitalized interest of $8 million and $7 million for the three months ended June 30, 2015 and 2014, respectively and $16 million and $13 million for the six months ended June 30, 2015 and 2014, respectively.

[3] Capital expenditures include changes in capital accruals. See Note 17 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

[4] Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

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Accumulated Other Comprehensive Loss

6 Months Ended

Jun. 30, 2015

Equity [Abstract]

Accumulated Other Comprehensive Loss

Accumulated Other Comprehensive Loss

The following table shows the changes in accumulated other comprehensive loss by component. Amounts in parentheses indicate debits.

(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2013	$	(161	)	$	(50	)	$	4	$	3		$	(204	)
Other comprehensive income (loss) before reclassifications	(65		)	8			—		(1		)	(58		)
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			1			—		—			27
– settlement loss(a)	69			—			—		—			69
Tax effect	(28		)	1			—		—			(27		)
Other comprehensive income (loss)	(21		)	8			—		(1		)	(14		)
Balance as of June 30, 2014	$	(182	)	$	(42	)	$	4	$	2		$	(218	)

(In millions)	Pension Benefits			Other Benefits			Gain on Cash Flow Hedge		Workers Compensation			Total
Balance as of December 31, 2014	$	(217	)	$	(104	)	$	4	$	4		$	(313	)
Other comprehensive loss before reclassifications	(12		)	14			—		(2		)	—
Amounts reclassified from accumulated other comprehensive loss:
Amortization – prior service credit(a)	(23		)	(2		)	—		—			(25		)
– actuarial loss(a)	26			4			—		—			30
– settlement loss(a)	2			—			—		—			2
Tax effect	(2		)	(1		)	—		—			(3		)
Other comprehensive income (loss)	(9		)	15			—		(2		)	4
Balance as of June 30, 2015	$	(226	)	$	(89	)	$	4	$	2		$	(309	)

^(a)  These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 19.

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Property, Plant And Equipment - Summary Of Property, Plant And Equipment (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 26,007	$ 25,302
Less accumulated depreciation	9,724	9,041
Net property, plant and equipment	16,283	16,261
Operating Segments | Refining & Marketing
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	18,434	18,001
Operating Segments | Speedway
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,762	4,639
Operating Segments | Pipeline Transportation
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,132	2,044
Corporate and Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 679	$ 618

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Segment Information (Tables)

6 Months Ended

Jun. 30, 2015

Segment Reporting [Abstract]

Income From Operations Attributable To Operating Segments

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2015
Revenues:
Customer	$	15,192	$	5,329	$	16	$	20,537
Intersegment(a)	3,425		2		148		3,575
Segment revenues	$	18,617	$	5,331	$	164	$	24,112
Segment income from operations(b)	$	1,206	$	127	$	79	$	1,412
Income from equity method investments	8		—		12		20
Depreciation and amortization(c)	268		62		19		349
Capital expenditures and investments(d)	207		100		157		464

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Three Months Ended June 30, 2014
Revenues:
Customer	$	22,917	$	3,908	$	19	$	26,844
Intersegment(a)	2,590		1		131		2,722
Segment revenues	$	25,507	$	3,909	$	150	$	29,566
Segment income from operations(b)	$	1,260	$	94	$	81	$	1,435
Income from equity method investments	35		—		22		57
Depreciation and amortization(c)	264		29		19		312
Capital expenditures and investments(d)	235		44		64		343

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2015
Revenues:
Customer	$	27,836	$	9,860	$	32	$	37,728
Intersegment(a)	6,158		2		282		6,442
Segment revenues	$	33,994	$	9,862	$	314	$	44,170
Segment income from operations(b)	$	2,522	$	295	$	146	$	2,963
Income from equity method investments	14		—		21		35
Depreciation and amortization(c)	535		125		39		699
Capital expenditures and investments(d)	436		145		238		819

(In millions)	Refining & Marketing		Speedway		Pipeline Transportation		Total
Six Months Ended June 30, 2014
Revenues:
Customer	$	42,727	$	7,366	$	36	$	50,129
Intersegment(a)	4,823		2		260		5,085
Segment revenues	$	47,550	$	7,368	$	296	$	55,214
Segment income from operations(b)	$	1,622	$	152	$	153	$	1,927
Income from equity method investments	59		—		33		92
Depreciation and amortization(c)	525		57		38		620
Capital expenditures and investments(d)	413		76		194		683

^(a)  Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below.

^(d)  Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.

Reconciliation Of Segment Income From Operations To Income Before Income Taxes

The following reconciles segment income from operations to income before income taxes as reported in the consolidated statements of income:

	Three Months Ended   June 30,						Six Months Ended   June 30,
(In millions)	2015			2014			2015			2014
Segment income from operations	$	1,412		$	1,435		$	2,963		$	1,927
Items not allocated to segments:
Corporate and other unallocated items(a)(b)	(76		)	(61		)	(156		)	(128		)
Pension settlement expenses(c)	(1		)	(5		)	(2		)	(69		)
Net interest and other financial income (costs)	(64		)	(48		)	(145		)	(94		)
Income before income taxes	$	1,271		$	1,321		$	2,660		$	1,636

^(a)  Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets.

^(b)  Corporate overhead expenses attributable to MPLX are included in the Pipeline Transportation segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments.

^(c)  See Note 19.

Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures

The following reconciles segment capital expenditures and investments to total capital expenditures:

	Three Months Ended   June 30,				Six Months Ended   June 30,
(In millions)	2015		2014		2015		2014
Segment capital expenditures and investments	$	464	$	343	$	819	$	683
Less: Investments in equity method investees	107		41		149		164
Plus: Items not allocated to segments:
Capital expenditures not allocated to segments	41		13		62		38
Capitalized interest	8		7		16		13
Total capital expenditures(a)	$	406	$	322	$	748	$	570

^(a)  Capital expenditures include changes in capital accruals. See Note 17 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

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Income Taxes

6 Months Ended

Jun. 30, 2015

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

The combined federal, state and foreign income tax rate was 34 percent and 35 percent for the three months ended June 30, 2015 and 2014, respectively and 35 percent for both the six months ended June 30, 2015 and 2014. The effective tax rate for the three and six months ended June 30, 2015 and 2014 is equivalent to or slightly less than the U.S. statutory rate of 35 percent primarily due to certain permanent benefit differences, including the domestic manufacturing deduction, partially offset by state and local tax expense.

We are continuously undergoing examination of our income tax returns, which have been completed for our U.S. federal and state income tax returns through the 2009 and 2003 tax years, respectively. We had $12 million of unrecognized tax benefits as of June 30, 2015. Pursuant to our tax sharing agreement with Marathon Oil, the unrecognized tax benefits related to pre-spinoff operations for which Marathon Oil was the taxpayer remain the responsibility of Marathon Oil and we have indemnified Marathon Oil accordingly. See Note 21 for indemnification information.