Marathon Petroleum (MPC) 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q1
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 Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		662,618,001

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Revenues and other income:
Sales and other operating revenues		$ 28,081	$ 18,694
Sales to related parties	[1]	186	172
Income from equity method investments		99	86
Net gain on disposal of assets		214	2
Other income		35	30
Total revenues and other income		28,615	18,984
Costs and expenses:
Cost of revenues (excludes items below)		25,756	17,370
Purchases from related parties	[2]	204	141
Depreciation and amortization		919	528
Selling, general and administrative expenses		881	402
Other taxes		186	103
Total costs and expenses		27,946	18,544
Income from operations		669	440
Net interest and other financial costs		306	183
Income before income taxes		363	257
Provision for income taxes		104	22
Net income		259	235
Less net income attributable to:
Redeemable noncontrolling interest		20	16
Noncontrolling interests		246	182
Net income (loss) attributable to MPC		$ (7)	$ 37
Basic:
Net income (loss) attributable to MPC per share		$ (0.01)	$ 0.08
Weighted average shares outstanding (in shares)		673	476
Diluted:
Net income (loss) attributable to MPC per share		$ (0.01)	$ 0.08
Weighted average shares outstanding (in shares)		673	480
[1]	Sales to related parties consists primarily of sales of refined products to PFJ Southeast, an equity affiliate which owns and operates travel plazas primarily in the Southeast region of the United States.
[2]	We obtain utilities, transportation services and purchase ethanol from certain of our equity affiliates.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 259	$ 235
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $6 and $3, respectively	(3)	7
Prior service costs, net of tax of ($8) and ($2), respectively	(3)	(7)
Other, net of tax of $0 and ($1), respectively	(1)	(2)
Other comprehensive loss	(7)	(2)
Comprehensive income	252	233
Less comprehensive income attributable to:
Redeemable noncontrolling interest	20	16
Noncontrolling interests	246	182
Comprehensive income (loss) attributable to MPC	$ (14)	$ 35

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Actuarial changes, tax	$ 6	$ 3
Prior service costs, tax	(8)	(2)
Other, tax	$ 0	$ (1)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 877	$ 1,687
Receivables, less allowance for doubtful accounts of $9 and $9, respectively	6,893	5,853
Inventories	9,833	9,837
Other current assets	548	646
Total current assets	18,151	18,023
Equity method investments	6,558	5,898
Property, plant and equipment, net	45,091	45,058
Goodwill	20,229	20,184
Right of use assets	2,680	0
Other noncurrent assets	3,727	3,777
Total assets	96,436	92,940
Current liabilities:
Accounts payable	10,568	9,366
Payroll and benefits payable	958	1,152
Accrued taxes	1,529	1,446
Debt due within one year	550	544
Operating lease liabilities	613	0
Other current liabilities	929	708
Total current liabilities	15,147	13,216
Long-term debt	27,565	26,980
Deferred income taxes	5,011	4,864
Defined benefit postretirement plan obligations	1,567	1,509
Long-term operating lease liabilities	2,153	0
Deferred credits and other liabilities	1,131	1,318
Total liabilities	52,574	47,887
Commitments and contingencies (see Note 24)
Redeemable noncontrolling interest	1,004	1,004
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 – 976 million and 975 million shares (par value $0.01 per share, 2 billion shares authorized)	10	10
Held in treasury, at cost – 309 million and 295 million shares	(14,063)	(13,175)
Additional paid-in capital	33,764	33,729
Retained earnings	14,391	14,755
Accumulated other comprehensive loss	(151)	(144)
Total MPC stockholders’ equity	33,951	35,175
Noncontrolling interests	8,907	8,874
Total equity	42,858	44,049
Total liabilities, redeemable noncontrolling interest and equity	$ 96,436	$ 92,940

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 9	$ 9
Preferred stock:
Shares issued	0	0
Shares outstanding	0	0
Par value	$ 0.01
Shares authorized	30,000,000
Common stock:
Shares issued	976,000,000	975,000,000
Par value	$ 0.01
Shares authorized	2,000,000,000
Treasury stock	(309,000,000)	(295,000,000)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net income	$ 259	$ 235
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred financing costs and debt discount	0	18
Depreciation and amortization	919	528
Pension and other postretirement benefits, net	52	32
Deferred income taxes	127	(19)
Net gain on disposal of assets	(214)	(2)
Income from equity method investments	(99)	(86)
Distributions from equity method investments	148	89
Changes in the fair value of derivative instruments	29	(14)
Changes in operating assets and liabilities, net of effects of businesses acquired:
Current receivables	(1,037)	96
Inventories	(4)	440
Current accounts payable and accrued liabilities	1,483	(1,455)
Right of use assets/operating leases	(1)	0
All other, net	(39)	1
Net cash provided by (used in) operating activities	1,623	(137)
Investing activities:
Additions to property, plant and equipment	(1,241)	(755)
Acquisitions, net of cash acquired	1	0
Disposal of assets	24	7
Investments – acquisitions, loans and contributions	(325)	(41)
Investments - redemptions, repayments and return of capital	2	0
All other, net	19	11
Net cash used in investing activities	(1,520)	(778)
Financing activities:
Long-term debt – borrowings	2,604	9,610
Long-term debt – repayments	(2,031)	(5,264)
Debt issuance costs	0	(53)
Issuance of common stock	2	12
Common stock repurchased	(885)	(1,327)
Dividends paid	(354)	(219)
Distributions to noncontrolling interests	(325)	(195)
Contributions from noncontrolling interests	95	1
All other, net	(26)	(8)
Net cash provided by (used in) financing activities	(920)	2,557
Net increase (decrease) in cash, cash equivalents and restricted cash	(817)	1,642
Cash, cash equivalents and restricted cash at beginning of period	1,725	3,015
Cash, cash equivalents and restricted cash at end of period	$ 908	$ 4,657

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle in period of adoption	$ 64				$ 63		$ 1
Beginning balance at Dec. 31, 2017	20,828	$ 7	$ (9,869)	$ 11,262	12,864	$ (231)	6,795
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	219				37		182
Dividends declared on common stock	(219)				(219)
Distributions to noncontrolling interests	(179)						(179)
Contributions from noncontrolling interests	1						1
Other comprehensive loss	(2)					(2)
Shares repurchased	(1,327)		(1,327)
Shares returned - stock based compensation			(4)
Shares issued - stock based compensation				27
Net shares issued - stock based compensation	24						1
Impact from equity transactions of MPLX & ANDX	(546)			2,380			(2,926)
Ending balance at Mar. 31, 2018	18,863	7	(11,200)	13,669	12,745	(233)	3,875
Beginning balance at Dec. 31, 2018	44,049	10	(13,175)	33,729	14,755	(144)	8,874
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	239				(7)		246
Dividends declared on common stock	(357)				(357)
Distributions to noncontrolling interests	(305)						(305)
Contributions from noncontrolling interests	95						95
Other comprehensive loss	(7)					(7)
Shares repurchased	(885)		(885)
Shares returned - stock based compensation			(3)
Shares issued - stock based compensation				32
Net shares issued - stock based compensation	28						(1)
Impact from equity transactions of MPLX & ANDX	2			3			(1)
Other	(1)						(1)
Ending balance at Mar. 31, 2019	$ 42,858	$ 10	$ (14,063)	$ 33,764	$ 14,391	$ (151)	$ 8,907

Consolidated Statement of Equit

Consolidated Statement of Equity - Shares of Common Stock - shares shares in Millions	Total	Common Stock
Beginning balance at Dec. 31, 2017		734
Number of common shares issued - stock compensation		0
Ending balance at Mar. 31, 2018		734
Beginning balance at Dec. 31, 2018	975	975
Number of common shares issued - stock compensation		1
Ending balance at Mar. 31, 2019	976	976

Consolidated Statements of Eq_2

Consolidated Statements of Equity - Shares of Treasury Stock - shares shares in Millions	Total	Treasury Stock
Beginning balance at Dec. 31, 2017		(248)
Number of shares repurchased	(19)	(19)
Number of shares returned - stock compensation		0
Ending balance at Mar. 31, 2018		(267)
Beginning balance at Dec. 31, 2018	(295)	(295)
Number of shares repurchased	(14)	(14)
Number of shares returned - stock compensation		0
Ending balance at Mar. 31, 2019	(309)	(309)

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interest - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Temporary Equity [Abstract]
Beginning balance	$ 1,004	$ 1,000
Net income attributable to redeemable noncontrolling interest	20	16
Distributions to noncontrolling interests	(20)	(16)
Ending balance	$ 1,004	$ 1,000

Consolidated Statements of Eq_3

Consolidated Statements of Equity and Redeemable Noncontrolling Interest (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared per share of common stock (in dollars per share)	$ 0.53	$ 0.46

Description of the Business and

Description of the Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business and Basis of Presentation	DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION Description of the Business We are a leading, integrated, downstream energy company headquartered in Findlay, Ohio. We operate the nation's largest refining system with more than 3 million barrels per day of crude oil capacity across 16 refineries. We sell refined products to wholesale marketing customers domestically and internationally, to buyers on the spot market, to consumers through our Retail business segment and to independent entrepreneurs who operate approximately 6,900 branded outlets. Our retail operations own and operate approximately 3,920 retail transportation fuel and convenience stores across the United States and also sell transportation fuel to consumers through approximately 1,060 direct dealer locations under long-term supply contracts. MPC’s midstream operations are primarily conducted through MPLX LP (“MPLX”) and Andeavor Logistics LP (“ANDX”), which own and operate crude oil and light product transportation and logistics infrastructure as well as gathering, processing, and fractionation assets. We own the general partner and majority limited partner interest in these two midstream companies. Refer to Note 4 for further information on the Andeavor acquisition, which closed on October 1, 2018, and to Notes 3 and 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 SEC applicable to interim period financial statements and do not include all of the information and disclosures required by 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, 2018 . The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results to be expected for the full year.

Accounting Standards

Accounting Standards	3 Months Ended
	Mar. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Adopted	ACCOUNTING STANDARDS Recently Adopted ASU 2016-02, Leases We adopted ASU No. 2016-02, Leases (“ASC 842”), as of January 1, 2019, electing the transition method which permits entities to adopt the provisions of the standard using the modified retrospective approach without adjusting comparative periods. We also elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to grandfather the historical accounting conclusions until a reassessment event is present. We have also elected the practical expedient to not recognize short-term leases on the balance sheet, the practical expedient related to right of way permits and land easements which allows us to carry forward our accounting treatment for those existing agreements, and the practical expedient to combine lease and non-lease components for the majority of our underlying classes of assets except for our third-party contractor service and equipment agreements and boat and barge equipment agreements in which we are the lessee. We did not elect the practical expedient to combine lease and non-lease components for arrangements in which we are the lessor. In instances where the practical expedient was not elected, lease and non-lease consideration is allocated based on relative standalone selling price. Right of use (“ROU”) assets represent our right to use an underlying asset in which we obtain substantially all of the economic benefits and the right to direct the use of the asset during the lease term. Lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term. We recognize ROU assets and lease liabilities on the balance sheet for leases with a lease term of greater than one year. Payments that are not fixed at the commencement of the lease are considered variable and are excluded from the ROU asset and lease liability calculations. In the measurement of our ROU assets and lease liabilities, the fixed lease payments in the agreement are discounted using a secured incremental borrowing rate for a term similar to the duration of the lease, as our leases do not provide implicit rates. Operating lease expense is recognized on a straight-line basis over the lease term. Adoption of the new standard resulted in the recording of ROU assets and lease liabilities of approximately $2.79 billion and $2.88 billion , respectively, as of January 1, 2019. The standard did not materially impact our consolidated statements of income, cash flows or equity as a result of adoption. As a lessor under ASC 842, MPLX may be required to re-classify existing operating leases to sales-type leases upon modification and related reassessment of the leases. If such a modification were to occur, it may result in the de-recognition of existing assets, recognition of a receivable in the amount of the present value of fixed payments expected to be received by MPLX under the lease, and recognition of a corresponding gain or loss in the period of change. MPLX will evaluate the impact of a lease reassessment as modifications occur. We also adopted the following ASUs during the first three months of 2019, none of which had a material impact to our financial statements or financial statement disclosures: ASU Effective Date 2018-02 Reporting Comprehensive Income - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income January 1, 2019 2017-12 Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities January 1, 2019
Not Yet Adopted	Not Yet Adopted ASU 2017-04, Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued an ASU which simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Under the new guidance, the recognition of an impairment charge is calculated based on the amount by which the carrying amount exceeds the reporting unit’s fair value, which could be different from the amount calculated under the current method using the implied fair value of the goodwill; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The guidance should be applied on a prospective basis, and is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. ASU 2016-13, Credit Losses - Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued an ASU related to the accounting for credit losses on certain financial instruments. The guidance requires that for most financial assets, losses be based on an expected loss approach which includes estimates of losses over the life of exposure that considers historical, current and forecasted information. Expanded disclosures related to the methods used to estimate the losses as well as a specific disaggregation of balances for financial assets are also required. The change is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. We do not expect application of this ASU to have a material impact on our consolidated financial statements.

Master Limited Partnerships

Master Limited Partnerships	3 Months Ended
	Mar. 31, 2019
Noncontrolling Interest [Abstract]
MPLX LP	MASTER LIMITED PARTNERSHIPS MPLX MPLX is a diversified, large-cap publicly traded limited partnership formed by us to own, operate, develop and acquire midstream energy infrastructure assets. MPLX is engaged in the transportation, storage and distribution of crude oil and refined petroleum products; gathering, processing and transportation of natural gas; and the gathering, transportation, fractionation, storage and marketing of NGLs. As of March 31, 2019 , we owned 64 percent of the outstanding MPLX common units and we control MPLX through our ownership of the general partner of MPLX. Dropdowns to MPLX and GP/IDR Exchange On February 1, 2018, we contributed refining logistics assets and fuels distribution services to MPLX in exchange for $4.1 billion in cash and approximately 112 million common units and 2 million general partner units from MPLX. MPLX financed the cash portion of the transaction with its $4.1 billion 364 -day term loan facility, which was entered into on January 2, 2018. We agreed to waive approximately one-third of the first quarter 2018 distributions on the common units issued in connection with this transaction. The contributions of these assets were accounted for as transactions between entities under common control and we did not record a gain or loss. Immediately following the February 1, 2018 dropdown to MPLX, our IDRs were cancelled and our economic general partner interest was converted into a non-economic general partner interest, all in exchange for 275 million newly issued MPLX common units (“GP/IDR Exchange”). As a result of this transaction, the general partner units and IDRs were eliminated, are no longer outstanding and no longer participate in distributions of cash from MPLX. Agreements We have various long-term, fee-based commercial agreements with MPLX. Under these agreements, MPLX provides transportation, storage, distribution and marketing services to us. Under certain agreements, we commit to provide MPLX with minimum throughput and distribution volumes of crude oil and refined products and minimum storage volumes of crude oil, refined products and butane. Under certain other agreements, we commit to pay for substantially all of the available capacity for certain marine transportation and refining logistics assets. These transactions are eliminated in consolidation, but are reflected as intersegment transactions between our Refining & Marketing and Midstream segments. We also have agreements with MPLX that establish fees for operational and management services provided between us and MPLX and for executive management services and certain general and administrative services provided by us to MPLX. These transactions are eliminated in consolidation, but are reflected as intersegment transactions between our Corporate and Midstream segments. ANDX Through the Andeavor acquisition, we acquired control of ANDX, which is a publicly traded limited partnership that was formed to own, operate, develop and acquire logistics assets. Its assets are integral to the success of our refining and marketing operations and are used to gather crude oil, natural gas, and water, process natural gas and distribute, transport and store crude oil and refined products. ANDX provides us with various pipeline transportation, trucking, terminal distribution, storage and petroleum-coke handling services under long-term, fee-based commercial agreements. With certain exceptions, these agreements generally contain minimum volume commitments. These transactions are eliminated in consolidation, but are reflected as intersegment transactions between our Refining & Marketing and Midstream segments. We also have agreements with ANDX that establish fees for operational and management services provided between us and ANDX and for executive management services and certain general and administrative services provided by us to ANDX. These transactions are eliminated in consolidation, but are reflected as intersegment transactions between our Corporate and Midstream segments. As of March 31, 2019 , we owned 64 percent of the outstanding ANDX common units. We also hold 80,000 ANDX TexNew Mex Units as of March 31, 2019 and control ANDX through our ownership of the general partner of ANDX. Noncontrolling Interest As a result of equity transactions of MPLX and ANDX, we are required to adjust non-controlling interest and additional paid-in capital. Changes in MPC’s additional paid-in capital resulting from changes in its ownership interests in MPLX and ANDX were as follows: Three Months Ended (In millions) 2019 2018 Increase due to the issuance of MPLX common units and general partner units to MPC $ — $ 1,114 Increase due to GP/IDR Exchange — 1,808 Increase due to the issuance of MPLX & ANDX common units 4 4 Increase in MPC's additional paid-in capital 4 2,926 Tax impact (1 ) (546 ) Increase in MPC's additional paid-in capital, net of tax $ 3 $ 2,380

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Acquisitions and Investments	ACQUISITIONS Acquisition of Andeavor On October 1, 2018, we acquired all the outstanding shares of Andeavor. The total value of consideration transferred was $23.46 billion , consisting of $19.97 billion in equity and $3.49 billion in cash. The cash portion of the purchase price was funded using cash on hand. Our financial results reflect the results of Andeavor from the date of the acquisition. We accounted for the Andeavor acquisition using the acquisition method of accounting, which requires Andeavor assets and liabilities to be recorded to our balance sheet at fair value as of the acquisition date. We will complete a final determination of the fair value of certain assets and liabilities within the one year measurement period from the date of the acquisition as required by FASB ASC Topic 805, “Business Combinations”. Due to the level of effort required to develop fair value measurements, the valuation studies necessary to determine the fair value of assets acquired and liabilities assumed are preliminary, including the underlying cash flows used to determine the fair value of identified intangible assets and economic obsolescence adjustments to property, plant and equipment. The size and the breadth of the Andeavor acquisition necessitates the use of the one year measurement period to fully analyze all the factors used in establishing the asset and liability fair values as of the acquisition date, including, but not limited to, property, plant and equipment, intangible assets, real property, leases, environmental and asset retirement obligations and the related tax impacts of any changes made. Any potential adjustments made could be material in relation to the preliminary values. During the three months ended March 31, 2019, we recorded adjustments to the preliminary fair value estimates of assets acquired and liabilities assumed as of the acquisition date as noted in the table below. (In millions) As originally reported Adjustments As adjusted Cash and cash equivalents $ 382 $ — $ 382 Receivables 2,744 (2 ) 2,742 Inventories 5,204 (8 ) 5,196 Other current assets 378 — 378 Equity method investments 865 — 865 Property, plant and equipment, net 16,545 (1 ) 16,544 Other noncurrent assets (a) 3,086 — 3,086 Total assets acquired 29,204 (11 ) 29,193 Accounts payable 4,003 — 4,003 Payroll and benefits payable 348 — 348 Accrued taxes 590 — 590 Debt due within one year 34 — 34 Other current liabilities 392 23 415 Long-term debt 8,875 1 8,876 Deferred income taxes 1,609 22 1,631 Defined benefit postretirement plan obligations 432 — 432 Deferred credit and other liabilities 714 6 720 Noncontrolling interests 5,059 3 5,062 Total liabilities and noncontrolling interest assumed 22,056 55 22,111 Net assets acquired excluding goodwill 7,148 (66 ) 7,082 Goodwill 16,314 66 16,380 Net assets acquired $ 23,462 $ — $ 23,462 (a) Includes intangible assets. The preliminary purchase consideration allocation resulted in the recognition of $16.38 billion in goodwill, of which $893 million is tax deductible due to a carryover basis from Andeavor. Our Refining & Marketing, Midstream and Retail segments recognized $4.78 billion , $7.72 billion and $3.88 billion of preliminary goodwill. The recognized goodwill represents the value expected to be created by further optimization of crude supply, a nationwide retail and marketing platform, diversification of our refining and midstream footprints and optimization of information systems and business processes. Pro Forma Financial Information The following unaudited pro forma financial information presents consolidated results assuming the Andeavor acquisition occurred on January 1, 2017. The unaudited pro forma information does not give effect to potential synergies that could result from the transaction and is not necessarily indicative of the results of future operations. Three Months Ended (In millions) 2018 Sales and other operating revenues $ 29,206 Net income attributable to MPC 26 The pro forma information includes adjustments to align accounting policies, including our policy to expense refinery turnarounds when they occur, an adjustment to depreciation expense to reflect the increased fair value of property, plant and equipment, increased amortization expense related to identifiable intangible assets and the related income tax effects. Acquisition of Express Mart During the fourth quarter of 2018, Speedway acquired 78 transportation fuel and convenience store locations from Petr-All Petroleum Consulting Corporation for total consideration of $266 million . These stores are located primarily in the Syracuse, Rochester and Buffalo markets in New York and had been operated under the Express Mart brand. Based on the final fair value estimates of assets acquired and liabilities assumed at the acquisition date, $97 million of the purchase price was allocated to property, plant and equipment, $9 million to inventory, $2 million to intangibles and $158 million to goodwill. Goodwill is tax deductible and represents the value expected to be created by geographically expanding our retail platform and the assembled workforce. These operations are accounted for within the Retail segment. Acquisition of Mt. Airy Terminal On September 26, 2018, MPLX acquired an eastern U.S. Gulf Coast export terminal (“Mt. Airy Terminal”) from Pin Oak Holdings, LLC for total consideration of $451 million . At the time of the acquisition, the terminal included tanks with 4 million barrels of third-party leased storage capacity and a dock with 120 mbpd of capacity. The Mt. Airy Terminal is located on the Mississippi River between New Orleans and Baton Rouge, near several Gulf Coast refineries, including our Garyville Refinery, and numerous rail lines and pipelines. The Mt. Airy Terminal is accounted for within the Midstream segment. In the first quarter of 2019, an adjustment to the initial purchase price was made for approximately $5 million related to the final settlement of the acquisition. This reduced the total purchase price to $446 million and resulted in $336 million of property, plant and equipment, $121 million of goodwill and the remainder being attributable to net liabilities assumed. Goodwill represents the significant growth potential of the terminal due to the multiple pipelines and rail lines which cross the property, the terminal’s position as an aggregation point for liquids growth in the region for both ocean-going vessels and inland barges, the proximity of the terminal to MPC’s Garyville refinery and other refineries in the region as well as the opportunity to construct an additional dock at the site. All of the goodwill recognized related to this transaction is tax deductible. Assuming the acquisitions of Express Mart and Mt. Airy Terminal had occurred on January 1, 2017, the consolidated pro forma results would not have been materially different from the reported results.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2019
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES Consolidated VIEs We control MPLX and ANDX through our ownership of the general partner of both entities. MPLX and ANDX are VIEs because the limited partners do not have substantive kick-out or substantive participating rights over the general partner. We are the primary beneficiary of both MPLX and ANDX because in addition to our significant economic interest, we also have the ability, through our ownership of the general partner, to control the decisions that most significantly impact MPLX and ANDX. We therefore consolidate MPLX and ANDX and record a noncontrolling interest for the interest owned by the public. We also record a redeemable noncontrolling interest related to MPLX’s preferred units. The creditors of MPLX and ANDX do not have recourse to MPC’s general credit through guarantees or other financial arrangements, except as noted. MPC has effectively guaranteed certain indebtedness of LOOP LLC (“LOOP”) and LOCAP LLC (“LOCAP”), in which MPLX holds an interest. See Note 24 for more information. Western Refining Southwest, Inc., a wholly-owned subsidiary of MPC and unitholder of ANDX, has guaranteed certain outstanding borrowings under the ANDX dropdown credit facility that were made in connection with the August 2018 dropdown transaction. The assets of MPLX and ANDX can only be used to settle their own obligations and their creditors have no recourse to our assets, except as noted above. The following table present balance sheet information for the assets and liabilities of MPLX and ANDX, which are included in our balance sheets. March 31, December 31, (In millions) MPLX ANDX (a) MPLX ANDX (a) Assets Cash and cash equivalents $ 93 $ 29 $ 68 $ 10 Receivables, less allowance for doubtful accounts 372 248 425 199 Inventories 74 21 77 22 Other current assets 34 37 45 57 Equity method investments 4,270 602 4,174 602 Property, plant and equipment, net 14,816 6,882 14,639 6,845 Goodwill 2,581 1,052 2,586 1,051 Right of use assets 262 122 — — Other noncurrent assets 448 1,235 458 1,242 Liabilities Accounts payable $ 583 $ 177 $ 776 $ 215 Payroll and benefits payable 4 1 2 10 Accrued taxes 40 20 48 23 Debt due within one year 1 503 1 504 Operating lease liabilities 46 12 — — Other current liabilities 189 117 177 77 Long-term debt 13,832 4,629 13,392 4,469 Deferred income taxes 12 1 13 1 Long-term operating lease liabilities 216 109 — — Deferred credits and other liabilities 289 66 276 68 (a) The balances reflected here are ANDX’s historical balances as the preliminary purchase accounting adjustments related to ANDX’s assets and liabilities in connection with the Andeavor acquisition and reflected on our consolidated balance sheets as of December 31, 2018 and March 31, 2019 have not yet been pushed down to this subsidiary.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS Transactions with related parties were as follows: Three Months Ended (In millions) 2019 2018 Sales to related parties (a) $ 186 $ 172 Purchases from related parties (b) 204 141 (a) Sales to related parties consists primarily of sales of refined products to PFJ Southeast, an equity affiliate which owns and operates travel plazas primarily in the Southeast region of the United States. (b) We obtain utilities, transportation services and purchase ethanol from certain of our equity affiliates. Summarized financial information, in the aggregate, for our significant equity method investments on a 100 percent basis were as follows: Three Months Ended (In millions) 2019 2018 Revenues and other income $ 1,628 $ 1,503 Income from operations 336 254 Net income 314 274

Income (Loss) per Common Share

Income (Loss) per Common Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Income per Common Share	INCOME (LOSS) PER COMMON SHARE We compute basic earnings per share by dividing net income attributable to MPC less income allocated to participating securities by the weighted average number of shares of common stock outstanding. Since MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities, we have calculated our earnings per share using the two-class method. Diluted income per share assumes exercise of certain stock-based compensation awards, provided the effect is not anti-dilutive. Three Months Ended (In millions, except per share data) 2019 2018 Basic earnings (loss) per share: Allocation of earnings: Net income (loss) attributable to MPC $ (7 ) $ 37 Income allocated to participating securities — — Income (loss) available to common stockholders – basic $ (7 ) $ 37 Weighted average common shares outstanding 673 476 Basic earnings (loss) per share $ (0.01 ) $ 0.08 Diluted earnings (loss) per share: Allocation of earnings: Net income (loss) attributable to MPC $ (7 ) $ 37 Income allocated to participating securities — — Income (loss) available to common stockholders – diluted $ (7 ) $ 37 Weighted average common shares outstanding 673 476 Effect of dilutive securities — 4 Weighted average common shares, including dilutive effect 673 480 Diluted earnings (loss) per share $ (0.01 ) $ 0.08 The following table summarizes the shares that were anti-dilutive and, therefore, were excluded from the diluted share calculation. Three Months Ended (In millions) 2019 2018 Shares issuable under stock-based compensation plans 7 —

Equity

Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Equity	EQUITY As of March 31, 2019 , we had $4.02 billion of share repurchase authorization remaining under authorizations from our board of directors. 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: Three Months Ended (In millions, except per share data) 2019 2018 Number of shares repurchased 14 19 Cash paid for shares repurchased $ 885 $ 1,327 Average cost per share $ 62.98 $ 68.74 As of March 31, 2019 , we had agreements to acquire 493,625 common shares for $30 million , which settled in early April 2019.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION We have three reportable segments: Refining & Marketing; Retail; and Midstream. 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 16 refineries in the West Coast, Mid-Continent and Gulf Coast regions of the United States, purchases refined products and ethanol for resale and distributes refined products through transportation, storage, distribution and marketing services provided largely by our Midstream segment. We sell refined products to wholesale marketing customers domestically and internationally, to buyers on the spot market, to our Retail business segment and to independent entrepreneurs who operate primarily Marathon ® branded outlets. • Retail – sells transportation fuels and convenience products in the retail market across the United States through company-owned and operated convenience stores, primarily under the Speedway ® brand, and long-term fuel supply contracts with direct dealers who operate locations primarily under the ARCO ® brand. • Midstream – transports, stores, distributes and markets crude oil and refined products principally for the Refining & Marketing segment via refining logistics assets, pipelines, terminals, towboats and barges; gathers, processes and transports natural gas; and gathers, transports, fractionates, stores and markets NGLs. The Midstream segment primarily reflects the results of MPLX and ANDX, our sponsored master limited partnerships. Segment income represents income from operations attributable to the reportable segments. Corporate administrative expenses, except for those attributable to MPLX and ANDX, and costs related to certain non-operating assets are not allocated to the Refining & Marketing and Retail 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 Retail Midstream Total Three Months Ended March 31, 2019 Revenues: Third party $ 19,751 $ 7,373 $ 957 $ 28,081 Intersegment 4,429 2 1,232 5,663 Related party 183 3 — 186 Segment revenues $ 24,363 $ 7,378 $ 2,189 $ 33,930 Segment income (loss) from operations $ (334 ) $ 170 $ 908 $ 744 Income from equity method investments 1 17 81 99 Depreciation and amortization (a) 427 126 307 860 Capital expenditures and investments (b) 394 73 823 1,290 (In millions) Refining & Marketing Retail Midstream Total Three Months Ended March 31, 2018 Revenues: Third party $ 13,412 $ 4,569 $ 713 $ 18,694 Intersegment 2,379 1 631 3,011 Related party 170 2 — 172 Segment revenues $ 15,961 $ 4,572 $ 1,344 $ 21,877 Segment income (loss) from operations $ (133 ) $ 95 $ 567 $ 529 Income from equity method investments 3 14 69 86 Depreciation and amortization (a) 252 79 181 512 Capital expenditures and investments (b) 191 39 482 712 (a) Differences between segment totals and MPC consolidated totals represent amounts related to corporate and other unallocated items and are included in items not allocated to segments in the reconciliation below. (b) Capital expenditures include changes in capital accruals and investments in affiliates. See reconciliation from segment totals to MPC consolidated total capital expenditures below. The following reconciles segment income from operations to income before income taxes as reported in the consolidated statements of income: Three Months Ended (In millions) 2019 2018 Segment income from operations $ 744 $ 529 Items not allocated to segments: Corporate and other unallocated items (a) (191 ) (89 ) Capline restructuring gain (b) 207 — Transaction-related costs (c) (91 ) — Income from operations 669 440 Net interest and other financial costs 306 183 Income before income taxes $ 363 $ 257 (a) Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets, except for corporate overhead expenses attributable to MPLX and ANDX, which are included in the Midstream segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Retail segments. (b) See Note 13 . (c) The transaction-related costs recognized in the first quarter largely relate to the recognition of an obligation for vacation benefits provided to former Andeavor employees. The following reconciles segment capital expenditures and investments to total capital expenditures: Three Months Ended (In millions) 2019 2018 Segment capital expenditures and investments $ 1,290 $ 712 Less investments in equity method investees 325 41 Plus items not allocated to segments: Corporate 10 18 Capitalized interest 31 18 Total capital expenditures (a) $ 1,006 $ 707 (a) Capital expenditures include changes in capital accruals. See Note 19 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

Net Interest and Other Financia

Net Interest and Other Financial Costs	3 Months Ended
	Mar. 31, 2019
Other Income and Expenses [Abstract]
Net Interest and Other Financial Costs	NET INTEREST AND OTHER FINANCIAL COSTS Net interest and other financial costs were as follows: Three Months Ended (In millions) 2019 2018 Interest income $ (9 ) $ (20 ) Interest expense 340 213 Interest capitalized (32 ) (18 ) Pension and other postretirement non-service costs (a) (3 ) — Loss on extinguishment of debt — 4 Other financial costs 10 4 Net interest and other financial costs $ 306 $ 183 (a) See Note 21 .

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The combined federal, state and foreign income tax rate was 29 percent and 9 percent for the three months ended March 31, 2019 and 2018 , respectively. The effective tax rate for the three months ended March 31, 2019 was greater than the U.S. statutory rate of 21 percent primarily due to $36 million of state deferred tax expense recorded as an out of period adjustment, partially offset by permanent tax differences related to net income attributable to noncontrolling interests. The effective tax rate for the three months ended March 31, 2018 was less than the U.S. statutory rate primarily due to certain permanent tax differences related to net income attributable to noncontrolling interests, state and local deferred tax benefits primarily resulting from the February 1 dropdown and GP/IDR Exchange and equity compensation. During the first quarter of 2019, MPC’s deferred tax liabilities increased $68 million with an offsetting increase to goodwill and the provision for income taxes of $32 million and $36 million , respectively for an out of period adjustment to correct the tax effects recorded in 2018 related to the Andeavor acquisition. The impact of the adjustment was not material to any previous period. We are continuously undergoing examination of our income tax returns, which have been completed through the 2005 tax year for state returns and the 2008 tax year for our U.S. federal return. As of March 31, 2019 , we had $231 million of unrecognized tax benefits. Prior to its spinoff on June 30, 2011, Marathon Petroleum Corporation was included in the Marathon Oil Corporation (“Marathon Oil”) U.S. federal income tax returns for all applicable years. During the third quarter of 2017, Marathon Oil received a notice of Final Partnership Administrative Adjustment (“FPAA”) from the U.S. Internal Revenue Service for taxable year 2010, relating to certain partnership transactions. Marathon Oil filed a U.S. Tax Court petition disputing these adjustments during the fourth quarter of 2017. We received an FPAA for taxable years 2011-2014 for items resulting from this matter and filed a U.S. Tax Court petition for tax years 2011-2014 to dispute these corollary adjustments in the fourth quarter of 2017. We continue to believe that the issue in dispute is more likely than not to be fully sustained and, therefore, no liability has been accrued for this matter. 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 24 for indemnification information.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Inventories	INVENTORIES (In millions) March 31, December 31, Crude oil and refinery feedstocks $ 3,689 $ 3,655 Refined products 5,186 5,234 Materials and supplies 744 720 Merchandise 214 228 Total $ 9,833 $ 9,837 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 LIFO method. There were no LIFO inventory liquidations recognized for the three months ended March 31, 2019 .

Equity Method Investments

Equity Method Investments	3 Months Ended
	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments and Joint Ventures Disclosure [Text Block]	EQUITY METHOD INVESTMENTS During the three months ended March 31, 2019 , we executed agreements with Capline Pipeline LLC (“Capline LLC”) to contribute our 33 percent undivided interest in Capline pipeline system in exchange for a 33 percent ownership interest in Capline LLC. Concurrent with our execution of these agreements, Capline LLC initiated a binding open season for southbound service from Patoka, IL to St. James, LA or Liberty, MS, with an additional origination point at Cushing, OK. Service from Cushing, OK is part of a joint tariff with Diamond pipeline. Crude oil service is expected to begin in the third quarter of 2020. In accordance with ASC 810 “Consolidation”, we derecognized our undivided interest amounting to $143 million of net assets and recognized the Capline LLC ownership interest we received at fair value. We used an income approach to determine the fair value of our ownership interest under a Monte Carlo simulation method. We determined the fair value of our ownership interest was estimated to be $350 million as of January 30, 2019. This is a nonrecurring fair value measurement and is categorized in level 3 of the fair value hierarchy. The Monte Carlo simulation inputs include ranges of tariff rates, operating volumes, operating cost and capital expenditure assumptions. The estimated cash flows were discounted using a Monte Carlo market participant weighted average cost of capital estimate. None of the inputs to the Monte Carlo simulation are individually significant. The excess of the estimated fair value of our ownership interest over the carrying value of the derecognized net assets resulted in a $207 million non cash net gain recorded as a net gain on disposal of assets in the accompanying consolidated statements of income. As the Capline system is currently idled, Capline LLC is unable to fund its operations without financial support from its equity owners and is a VIE. MPC is not deemed to be the primary beneficiary, due to our inability to unilaterally control significant decision-making rights. Our maximum exposure to loss as a result of our involvement with Capline LLC includes our equity investment, any additional capital contribution commitments and any operating expenses incurred by Capline LLC in excess of compensation received for performance of the operating services.

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT (In millions) March 31, December 31, Refining & Marketing $ 27,968 $ 27,590 Retail 6,681 6,637 Midstream 25,929 25,692 Corporate and Other 1,304 1,294 Total 61,882 61,213 Less accumulated depreciation 16,791 16,155 Property, plant and equipment, net $ 45,091 $ 45,058

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 and December 31, 2018 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. March 31, 2019 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 Assets: Commodity contracts $ 122 $ 18 $ — $ (128 ) $ 12 $ 42 Liabilities: Commodity contracts $ 142 $ 24 $ — $ (161 ) $ 5 $ — Embedded derivatives in commodity contracts — — 65 — 65 — December 31, 2018 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 Assets: Commodity contracts $ 370 $ 31 $ — $ (323 ) $ 78 $ 2 Liabilities: Commodity contracts $ 255 $ 37 $ — $ (284 ) $ 8 $ — Embedded derivatives in commodity contracts — — 61 — 61 — (a) Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of March 31, 2019 , cash collateral of $33 million was netted with the mark-to-market derivative liabilities. As of December 31, 2018 , cash collateral of $52 million was netted with mark-to-market derivative assets and $13 million was netted with mark-to-market derivative liabilities. (b) We have no derivative contracts that are subject to master netting arrangements reflected gross on the balance sheet. 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. Level 2 instruments are valued based on quoted prices for similar assets and liabilities in active markets, and inputs other than quoted prices, such as liquidity, that are observable for the asset or liability. Commodity derivatives in Level 2 are OTC contracts, which are valued using market quotations from independent price reporting agencies, third-party brokers and commodity exchange price curves that are corroborated with market data. Level 3 instruments are OTC NGL contracts and embedded derivatives in commodity contracts. The embedded derivative liability relates to a natural gas purchase agreement embedded in a keep‑whole processing agreement. The fair value calculation for these Level 3 instruments at March 31, 2019 used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.60 to $1.25 per gallon and (2) the probability of renewal of 91 percent for the first five -year term and 82 percent for the second five -year term of the natural gas purchase agreement and the related keep-whole processing agreement. For these contracts, increases in forward NGL prices result in a decrease in the fair value of the derivative assets and an increase in the fair value of the derivative liabilities. Increases or decreases in the fractionation spread result in an increase or decrease in the fair value of the embedded derivative liability. An increase in the probability of renewal would result in an increase in the fair value of the related embedded derivative liability. The following is a reconciliation of the beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy. Three Months Ended (In millions) 2019 2018 Beginning balance $ 61 $ 66 Unrealized and realized losses included in net income 6 (3 ) Settlements of derivative instruments (2 ) (3 ) Ending balance $ 65 $ 60 The amount of total losses for the period included in earnings attributable to the change in unrealized losses relating to assets still held at the end of period: $ 5 $ (3 ) Fair Values – Reported We believe the carrying value of our other financial instruments, including cash and cash equivalents, receivables, accounts payable and certain accrued liabilities, approximate fair value. Our fair value assessment incorporates a variety of considerations, including the short-term duration of the instruments and the expected insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. The borrowings under our revolving credit facilities, which include variable interest rates, approximate fair value. The fair value of our fixed rate long-term debt is based on prices from recent trade activity and is categorized in level 3 of the fair value hierarchy. The carrying and fair values of our debt were approximately $27.6 billion and $28.5 billion at March 31, 2019 , respectively, and approximately $27.0 billion and $26.5 billion at December 31, 2018 , respectively. These carrying and fair values of our debt exclude the unamortized issuance costs which are netted against our total debt.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2019
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 15 . 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, (4) the acquisition of ethanol for blending with refined products, (5) the sale of NGLs and (6) the purchase of natural gas. The following table presents the fair value of derivative instruments as of March 31, 2019 and December 31, 2018 and the line items in the balance sheets in which the fair values are reflected. The fair value amounts below are presented on a gross basis and do not reflect the netting of asset and liability positions permitted under the terms of our master netting arrangements including cash collateral on deposit with, or received from, brokers. We offset the recognized fair value amounts for multiple derivative instruments executed with the same counterparty in our financial statements when a legal right of offset exists. As a result, the asset and liability amounts below will not agree with the amounts presented in our consolidated balance sheets. (In millions) March 31, 2019 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 139 $ 160 Other current liabilities (a) 1 14 Deferred credits and other liabilities (a) — 57 (In millions) December 31, 2018 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 400 $ 283 Other current liabilities (a) 1 16 Deferred credits and other liabilities (a) — 54 (a) Includes embedded derivatives. The table below summarizes open commodity derivative contracts for crude oil, refined products and blending products as of March 31, 2019 . Percentage of contracts that expire next quarter Position (Units in thousands of barrels) Long Short Exchange-traded (a) Crude oil 82.6% 49,844 58,466 Refined products 89.4% 11,373 9,945 Blending products 77.3% 4,688 4,866 OTC Crude oil —% 640 — Blending products —% 1,676 1,444 (a) Included in exchange-traded are spread contracts in thousands of barrels: Crude oil - 11,999 long and 3,980 short; Refined products - 300 long and 300 short; Blending products - 2,603 long and 2,506 short The following table summarizes the effect of all commodity derivative instruments in our consolidated statements of income: Loss (In millions) Three Months Ended March 31, Income Statement Location 2019 2018 Sales and other operating revenues $ (20 ) $ (1 ) Cost of revenues (80 ) (27 ) Total $ (100 ) $ (28 )

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	DEBT Our outstanding borrowings at March 31, 2019 and December 31, 2018 consisted of the following: (In millions) March 31, December 31, Marathon Petroleum Corporation $ 9,120 $ 9,114 MPLX LP 14,283 13,856 ANDX LP 5,168 5,010 Total debt $ 28,571 $ 27,980 Unamortized debt issuance costs (126 ) (128 ) Unamortized discount (330 ) (328 ) Amounts due within one year (550 ) (544 ) Total long-term debt due after one year $ 27,565 $ 26,980 Available Capacity under our Facilities (Dollars in millions) Total Capacity Outstanding Borrowings Outstanding Letters of Credit Available Capacity Weighted Average Interest Rate Expiration MPC 364-day bank revolving credit facility $ 1,000 $ — $ — $ 1,000 — September 2019 MPC bank revolving credit facility 5,000 — 32 4,968 — October 2023 MPLX bank revolving credit facility 2,250 425 3 1,822 3.92 % July 2022 ANDX revolving & dropdown credit facilities (a) 2,100 1,404 — 696 4.32 % January 2021 Trade receivables securitization facility 750 — — 750 — July 2019 $ 11,100 $ 1,829 $ 35 $ 9,236 (a) Western Refining Southwest, Inc., a wholly-owned subsidiary of MPC and unitholder of ANDX, has guaranteed certain outstanding borrowings under the ANDX dropdown credit facility that were made in connection with the August 2018 dropdown transaction.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE The following table presents our revenues disaggregated by product line. Three Months Ended (In millions) 2019 2018 Refined products $ 24,653 $ 16,158 Merchandise 1,464 1,130 Crude oil and refinery feedstocks 1,367 883 Midstream services, transportation and other 597 523 Sales and other operating revenues $ 28,081 $ 18,694 Practical Expedients On January 1, 2018, we adopted ASU 2014-09, Revenue - Revenue from Contracts with Customers (“ASC 606”). We elected the completed contract practical expedient and only applied ASC 606 to contracts that were not completed as of January 1, 2018. We do not disclose information on the future performance obligations for any contract with expected duration of one year or less at inception. As of March 31, 2019 , we do not have future performance obligations that are material to future periods. Receivables On the accompanying consolidated balance sheets, receivables, less allowance for doubtful accounts primarily consists of customer receivables. Significant, non-customer balances included in our receivables at March 31, 2019 include matching buy/sell receivables of $1.98 billion and income tax receivables of $76 million .

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION Three Months Ended (In millions) 2019 2018 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 269 $ 212 Net income taxes paid to taxing authorities 42 6 Cash paid for amounts included in the measurement of lease liabilities Payments on operating leases 189 — Interest payments under finance lease obligations 8 — Net cash provided by financing activities included: Principal payments under finance lease obligations 10 — Non-cash investing and financing activities: Right of use assets obtained in exchange for new operating lease obligations 31 — Right of use assets obtained in exchange for new finance lease obligations 15 — Contribution of net assets to Capline LLC (a) 143 — Recognition of Capline LLC equity method investment (a) 350 — (a) See Note 13 . (In millions) March 31, December 31, Cash and cash equivalents $ 877 $ 1,687 Restricted cash (a) 31 38 Cash, cash equivalents and restricted cash $ 908 $ 1,725 (a) The restricted cash balance is included within other current assets on the consolidated balance sheets. 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: Three Months Ended (In millions) 2019 2018 Additions to property, plant and equipment per the consolidated statements of cash flows $ 1,241 $ 755 Asset retirement expenditures — 1 Decrease in capital accruals (235 ) (49 ) Total capital expenditures $ 1,006 $ 707

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2019
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, 2017 $ (190 ) $ (48 ) $ 4 $ 3 $ (231 ) Other comprehensive loss before reclassifications — — (2 ) — (2 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (8 ) (1 ) — — (9 ) – actuarial loss (a) 9 — — — 9 – settlement loss (a) 1 — — — 1 Other — — — — — Tax effect (1 ) — — — (1 ) Other comprehensive income (loss) 1 (1 ) (2 ) — (2 ) Balance as of March 31, 2018 $ (189 ) $ (49 ) $ 2 $ 3 $ (233 ) (In millions) Pension Benefits Other Benefits Gain on Cash Flow Hedge Workers Compensation Total Balance as of December 31, 2018 $ (132 ) $ (23 ) $ 2 $ 9 $ (144 ) Other comprehensive loss before reclassifications (1 ) — — — (1 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (11 ) — — — (11 ) – actuarial loss (a) 4 — — — 4 – settlement loss (a) — — — — — Other — — — (1 ) (1 ) Tax effect 2 — — — 2 Other comprehensive loss (6 ) — — (1 ) (7 ) Balance as of March 31, 2019 $ (138 ) $ (23 ) $ 2 $ 8 $ (151 ) (a) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 21 .

Defined Benefit Pension and Oth

Defined Benefit Pension and Other Postretirement Plans	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [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 March 31, Pension Benefits Other Benefits (In millions) 2019 2018 2019 2018 Components of net periodic benefit cost: Service cost $ 58 $ 36 $ 8 $ 7 Interest cost 28 18 9 7 Expected return on plan assets (32 ) (26 ) — — Amortization – prior service credit (11 ) (8 ) — (1 ) – actuarial loss 4 9 — — – settlement loss — 1 — — Net periodic benefit cost $ 47 $ 30 $ 17 $ 13 The components of net periodic benefit cost other than the service cost component are included in net interest and other financial costs on the consolidated statements of income. During the three months ended March 31, 2019 , we made no contributions to our funded pension plans. Benefit payments related to unfunded pension and other postretirement benefit plans were $3 million and $11 million , respectively, during the three months ended March 31, 2019 .

Stock-Based Compensation Plans

Stock-Based Compensation Plans	3 Months Ended
	Mar. 31, 2019
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 three months ended March 31, 2019 : Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 8,724,595 $ 37.07 Granted 1,037,671 62.68 Exercised (229,169 ) 10.62 Forfeited or expired — — Outstanding at March 31, 2019 9,533,097 40.49 The grant date fair value of stock option awards granted during the three months ended March 31, 2019 was $14.34 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 and Restricted Stock Unit Awards The following table presents a summary of restricted stock and restricted stock unit award activity for the three months ended March 31, 2019 : Restricted Stock Restricted Stock Units Number of Shares Weighted Average Grant Date Fair Value Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2018 990,700 $ 57.23 4,226,856 $ 80.96 Granted 158,120 62.66 8,050 59.56 Vested (114,136 ) 49.58 (1,110,705 ) 82.43 Forfeited (12,622 ) 56.84 (46,923 ) 82.43 Outstanding at March 31, 2019 1,022,062 58.93 3,077,278 80.35 Performance Unit Awards The following table presents a summary of the activity for performance unit awards to be settled in shares for the three months ended March 31, 2019 : Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2018 8,618,583 $ 0.79 Granted 6,200,000 0.72 Vested (2,280,333 ) 0.57 Forfeited (120,000 ) 0.84 Outstanding at March 31, 2019 12,418,250 0.79 The performance unit awards granted during the three months ended March 31, 2019 have a grant date fair value of $0.72 per unit, as calculated using a Monte Carlo valuation model. MPLX and ANDX Awards Compensation expense for MPLX and ANDX equity awards was not material to our consolidated financial statements for the three months ended March 31, 2019 .

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases of Lessee Disclosure	LEASES For further information regarding the adoption of ASC 842, including the method of adoption and practical expedients elected, see Note 2 . Lessee We lease a wide variety of facilities and equipment including land and building space, office and field equipment, storage facilities and transportation equipment. Our remaining lease terms range from less than one year to 60 years . Most long-term leases include renewal options ranging from less than one year to 49 years and, in certain leases, also include purchase options. The lease term included in the measurement of right of use assets and lease liabilities includes options to extend or terminate our leases that we are reasonably certain to exercise. Options were included in the lease term primarily for retail store sites where we constructed property, plant and equipment on leased land that is expected to exist beyond the initial lease term. Under ASC 842, the components of lease cost were as follows: Three Months Ended (In millions) 2019 Finance lease cost: Amortization of right of use assets $ 14 Interest on lease liabilities 10 Operating lease cost 190 Variable lease cost 15 Short-term lease cost 152 Total lease cost $ 381 Supplemental balance sheet data related to leases were as follows: (In millions) March 31, 2019 Operating leases Assets Right of use assets $ 2,680 Liabilities Operating lease liabilities $ 613 Long-term operating lease liabilities 2,153 Total operating lease liabilities $ 2,766 Weighted average remaining lease term 6.5 years Weighted average discount rate 4.13 % Finance leases Assets Property, plant and equipment, gross $ 760 Accumulated depreciation 206 Property, plant and equipment, net $ 554 Liabilities Debt due within one year $ 45 Long-term debt 612 Total finance lease liabilities $ 657 Weighted average remaining lease term 13.2 years Weighted average discount rate 6.02 % As of March 31, 2019 , maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Operating Finance 2019 $ 554 $ 57 2020 629 76 2021 545 69 2022 370 76 2023 262 83 2024 and thereafter 832 596 Gross lease payments 3,192 957 Less: imputed interest 426 300 Total lease liabilities $ 2,766 $ 657
Leases of Lessor Disclosure	Lessor MPLX has certain natural gas gathering, transportation and processing agreements in which it is considered to be the lessor under several implicit operating lease arrangements in accordance with GAAP. MPLX’s primary implicit lease operations relate to a natural gas gathering agreement in the Marcellus region for which it earns a fixed-fee for providing gathering services to a single producer using a dedicated gathering system. As the gathering system is expanded, the fixed-fee charged to the producer is adjusted to include the additional gathering assets in the lease. The primary term of the natural gas gathering arrangement expires in 2038 and will continue thereafter on a year-to-year basis until terminated by either party. Other significant implicit leases relate to a natural gas processing agreement in the Marcellus region and a natural gas processing agreement in the Southern Appalachia region for which MPLX earns minimum monthly fees for providing processing services to a single producer using a dedicated processing plant. The primary term of these natural gas processing agreements expire during 2023 and 2033. MPLX did not elect to use the practical expedient to combine lease and non-lease components for lessor arrangements. The tables below represent the portion of the contract allocated to the lease component based on relative standalone selling price. Lessor agreements are currently deemed operating, as we elected the practical expedient to grandfather in old conclusions. We are still determining the impact of the new standard on these arrangements if and when a modification occurs and they are required to be assessed under ASC 842. MPLX may be required to re-classify existing operating leases to sales-type leases upon modification and related reassessment of the leases. Our revenue from implicit lease arrangements, excluding executory costs, totaled approximately $60 million in the three months ended March 31, 2019 . The implicit lease arrangements related to the processing facilities contain contingent rental provisions whereby we receive additional fees if the producer customer exceeds the monthly minimum processed volumes. During the three months ended March 31, 2019 , MPLX did not receive any material contingent lease payments. The following is a schedule of minimum future rentals on the non‑cancellable operating leases as of March 31, 2019 : (In millions) 2019 $ 144 2020 168 2021 162 2022 160 2023 154 2024 and thereafter 1,205 Total minimum future rentals $ 1,993 The following schedule summarizes our investment in assets held for operating lease by major classes as of March 31, 2019 : (In millions) March 31, 2019 Natural gas gathering and NGL transportation pipelines and facilities $ 1,036 Natural gas processing facilities 642 Terminal and related assets 112 Land, building, office equipment and other 41 Property, plant and equipment 1,831 Less accumulated depreciation 261 Property, plant and equipment, net $ 1,570

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
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 a liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings. 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 March 31, 2019 and December 31, 2018 , accrued liabilities for remediation totaled $451 million and $455 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, were $33 million and $35 million at March 31, 2019 and December 31, 2018 , respectively. Governmental and other entities in California, New York, Maryland and Rhode Island have filed lawsuits against coal, gas, oil and petroleum companies, including the Company. The lawsuits allege damages as a result of climate change and the plaintiffs are seeking unspecified damages and abatement under various tort theories. Similar lawsuits may be filed in other jurisdictions. At this early stage, the ultimate outcome of these matters remain uncertain, and neither the likelihood of an unfavorable outcome nor the ultimate liability, if any, can be determined. 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 (“MPC LP”), 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 MPC LP 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 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 million during 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 on our consolidated financial position, results of operations, or cash flows. 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 —MPC and MPLX hold interests in an offshore oil port, LOOP, and MPLX holds an interest in a crude oil pipeline system, LOCAP. Both LOOP and LOCAP have secured various project financings with throughput and deficiency agreements. Under the agreements, MPC, as a shipper, is 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 $171 million as of March 31, 2019 . In connection with MPLX’s approximate nine percent indirect interest in a joint venture that owns and operates the Dakota Access Pipeline and Energy Transfer Crude Oil Pipeline projects, collectively referred to as the Bakken Pipeline system, MPLX has entered into a Contingent Equity Contribution Agreement. MPLX, along with the other joint venture owners in the Bakken Pipeline system, have agreed to make equity contributions to the joint venture upon certain events occurring to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. The senior notes were issued to repay amounts owed by the pipeline companies to fund the cost of construction of the Bakken Pipeline system. As of March 31, 2019 , our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement was approximately $230 million . In connection with our 50 percent indirect interest in Crowley Ocean Partners, we have agreed to conditionally guarantee our portion of the obligations of the joint venture and its subsidiaries under a senior secured term loan agreement. The term loan agreement provides for loans of up to $325 million to finance the acquisition of four product tankers. MPC’s liability under the guarantee for each vessel is conditioned upon the occurrence of certain events, including if we cease to maintain an investment grade credit rating or the charter for the relevant product tanker ceases to be in effect and is not replaced by a charter with an investment grade company on certain defined commercial terms. As of March 31, 2019 , our maximum potential undiscounted payments under this agreement for debt principal totaled $135 million . In connection with our 50 percent indirect interest in Crowley Blue Water Partners, we have agreed to provide a conditional guarantee of up to 50 percent of its outstanding debt balance in the event there is no charter agreement in place with an investment grade customer for the entity’s three vessels as well as other financial support in certain circumstances. As of March 31, 2019 , our maximum potential undiscounted payments under this arrangement was $125 million . 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 $1 million as of March 31, 2019 , 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 $123 million as of March 31, 2019 , which primarily consist of a commitment to contribute cash to an equity method investee for certain catastrophic events, in lieu of procuring insurance coverage, a commitment to fund a share of the bonds issued by a government entity for construction of public utilities in the event that other industrial users of the facility default on their utility payments and leases of assets containing general lease indemnities and guaranteed residual values. See Note 5 for information regarding our guarantee of certain borrowings under the ANDX dropdown credit facility. 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 and Contingencies At March 31, 2019 , our contractual commitments to acquire property, plant and equipment and advance funds to equity method investees totaled $1.06 billion . Certain natural gas processing and gathering arrangements require us to construct natural gas processing plants, natural gas gathering pipelines and NGL pipelines and contain certain fees and charges if specified construction milestones are not achieved for reasons other than force majeure. In certain cases, certain producer customers may have the right to cancel the processing arrangements with us if there are significant delays that are not due to force majeure.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENT On May 8, 2019, MPC, MPLX and ANDX announced that MPLX and ANDX have entered into a definitive merger agreement whereby MPLX will acquire ANDX in a unit-for-unit transaction. Under the terms of the merger agreement, ANDX public unitholders will receive 1.135 MPLX common units for each ANDX common unit held and MPC will receive 1.0328 MPLX common units for each ANDX common unit held. As described in Notes 4 and 5 , we consolidate ANDX in accordance with ASC 810 and previously recorded ANDX’s assets and liabilities to our balance sheet at preliminary fair values as of the Andeavor acquisition date of October 1, 2018. Upon closing of this merger, we will account for the unit-for-unit transaction as a common control transaction, which will result in a change in our noncontrolling interest and additional paid-in capital. The transaction has been approved by MPLX’s and ANDX’s respective Conflicts Committees and both Boards of Directors. Subject to the satisfaction of customary closing conditions and receipt of regulatory approvals, the transaction is expected to close in the second half of 2019.

Description of the Business a_2

Description of the Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [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 SEC applicable to interim period financial statements and do not include all of the information and disclosures required by 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 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, (4) the acquisition of ethanol for blending with refined products, (5) the sale of NGLs and (6) the purchase of natural gas.
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.

Master Limited Partnerships (Ta

Master Limited Partnerships (Tables)	3 Months Ended
	Mar. 31, 2019
Noncontrolling Interest [Abstract]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net	As a result of equity transactions of MPLX and ANDX, we are required to adjust non-controlling interest and additional paid-in capital. Changes in MPC’s additional paid-in capital resulting from changes in its ownership interests in MPLX and ANDX were as follows: Three Months Ended (In millions) 2019 2018 Increase due to the issuance of MPLX common units and general partner units to MPC $ — $ 1,114 Increase due to GP/IDR Exchange — 1,808 Increase due to the issuance of MPLX & ANDX common units 4 4 Increase in MPC's additional paid-in capital 4 2,926 Tax impact (1 ) (546 ) Increase in MPC's additional paid-in capital, net of tax $ 3 $ 2,380

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	During the three months ended March 31, 2019, we recorded adjustments to the preliminary fair value estimates of assets acquired and liabilities assumed as of the acquisition date as noted in the table below. (In millions) As originally reported Adjustments As adjusted Cash and cash equivalents $ 382 $ — $ 382 Receivables 2,744 (2 ) 2,742 Inventories 5,204 (8 ) 5,196 Other current assets 378 — 378 Equity method investments 865 — 865 Property, plant and equipment, net 16,545 (1 ) 16,544 Other noncurrent assets (a) 3,086 — 3,086 Total assets acquired 29,204 (11 ) 29,193 Accounts payable 4,003 — 4,003 Payroll and benefits payable 348 — 348 Accrued taxes 590 — 590 Debt due within one year 34 — 34 Other current liabilities 392 23 415 Long-term debt 8,875 1 8,876 Deferred income taxes 1,609 22 1,631 Defined benefit postretirement plan obligations 432 — 432 Deferred credit and other liabilities 714 6 720 Noncontrolling interests 5,059 3 5,062 Total liabilities and noncontrolling interest assumed 22,056 55 22,111 Net assets acquired excluding goodwill 7,148 (66 ) 7,082 Goodwill 16,314 66 16,380 Net assets acquired $ 23,462 $ — $ 23,462 (a) Includes intangible assets.
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma financial information presents consolidated results assuming the Andeavor acquisition occurred on January 1, 2017. The unaudited pro forma information does not give effect to potential synergies that could result from the transaction and is not necessarily indicative of the results of future operations. Three Months Ended (In millions) 2018 Sales and other operating revenues $ 29,206 Net income attributable to MPC 26

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2019
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	The assets of MPLX and ANDX can only be used to settle their own obligations and their creditors have no recourse to our assets, except as noted above. The following table present balance sheet information for the assets and liabilities of MPLX and ANDX, which are included in our balance sheets. March 31, December 31, (In millions) MPLX ANDX (a) MPLX ANDX (a) Assets Cash and cash equivalents $ 93 $ 29 $ 68 $ 10 Receivables, less allowance for doubtful accounts 372 248 425 199 Inventories 74 21 77 22 Other current assets 34 37 45 57 Equity method investments 4,270 602 4,174 602 Property, plant and equipment, net 14,816 6,882 14,639 6,845 Goodwill 2,581 1,052 2,586 1,051 Right of use assets 262 122 — — Other noncurrent assets 448 1,235 458 1,242 Liabilities Accounts payable $ 583 $ 177 $ 776 $ 215 Payroll and benefits payable 4 1 2 10 Accrued taxes 40 20 48 23 Debt due within one year 1 503 1 504 Operating lease liabilities 46 12 — — Other current liabilities 189 117 177 77 Long-term debt 13,832 4,629 13,392 4,469 Deferred income taxes 12 1 13 1 Long-term operating lease liabilities 216 109 — — Deferred credits and other liabilities 289 66 276 68 (a) The balances reflected here are ANDX’s historical balances as the preliminary purchase accounting adjustments related to ANDX’s assets and liabilities in connection with the Andeavor acquisition and reflected on our consolidated balance sheets as of December 31, 2018 and March 31, 2019 have not yet been pushed down to this subsidiary.

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Sales to Related Parties	Transactions with related parties were as follows: Three Months Ended (In millions) 2019 2018 Sales to related parties (a) $ 186 $ 172 Purchases from related parties (b) 204 141 (a) Sales to related parties consists primarily of sales of refined products to PFJ Southeast, an equity affiliate which owns and operates travel plazas primarily in the Southeast region of the United States. (b) We obtain utilities, transportation services and purchase ethanol from certain of our equity affiliates.
Summarized Financial Information For Equity Method Investees Table [Table Text Block]	Summarized financial information, in the aggregate, for our significant equity method investments on a 100 percent basis were as follows: Three Months Ended (In millions) 2019 2018 Revenues and other income $ 1,628 $ 1,503 Income from operations 336 254 Net income 314 274

Income (Loss) per Common Share

Income (Loss) per Common Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Summary of Earnings Per Common Share	We compute basic earnings per share by dividing net income attributable to MPC less income allocated to participating securities by the weighted average number of shares of common stock outstanding. Since MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities, we have calculated our earnings per share using the two-class method. Diluted income per share assumes exercise of certain stock-based compensation awards, provided the effect is not anti-dilutive. Three Months Ended (In millions, except per share data) 2019 2018 Basic earnings (loss) per share: Allocation of earnings: Net income (loss) attributable to MPC $ (7 ) $ 37 Income allocated to participating securities — — Income (loss) available to common stockholders – basic $ (7 ) $ 37 Weighted average common shares outstanding 673 476 Basic earnings (loss) per share $ (0.01 ) $ 0.08 Diluted earnings (loss) per share: Allocation of earnings: Net income (loss) attributable to MPC $ (7 ) $ 37 Income allocated to participating securities — — Income (loss) available to common stockholders – diluted $ (7 ) $ 37 Weighted average common shares outstanding 673 476 Effect of dilutive securities — 4 Weighted average common shares, including dilutive effect 673 480 Diluted earnings (loss) per share $ (0.01 ) $ 0.08
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table summarizes the shares that were anti-dilutive and, therefore, were excluded from the diluted share calculation. Three Months Ended (In millions) 2019 2018 Shares issuable under stock-based compensation plans 7 —

Equity (Tables)

Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Share Repurchases	Total share repurchases were as follows: Three Months Ended (In millions, except per share data) 2019 2018 Number of shares repurchased 14 19 Cash paid for shares repurchased $ 885 $ 1,327 Average cost per share $ 62.98 $ 68.74

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Income From Operations Attributable To Operating Segments	Segment income represents income from operations attributable to the reportable segments. Corporate administrative expenses, except for those attributable to MPLX and ANDX, and costs related to certain non-operating assets are not allocated to the Refining & Marketing and Retail 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 Retail Midstream Total Three Months Ended March 31, 2019 Revenues: Third party $ 19,751 $ 7,373 $ 957 $ 28,081 Intersegment 4,429 2 1,232 5,663 Related party 183 3 — 186 Segment revenues $ 24,363 $ 7,378 $ 2,189 $ 33,930 Segment income (loss) from operations $ (334 ) $ 170 $ 908 $ 744 Income from equity method investments 1 17 81 99 Depreciation and amortization (a) 427 126 307 860 Capital expenditures and investments (b) 394 73 823 1,290 (In millions) Refining & Marketing Retail Midstream Total Three Months Ended March 31, 2018 Revenues: Third party $ 13,412 $ 4,569 $ 713 $ 18,694 Intersegment 2,379 1 631 3,011 Related party 170 2 — 172 Segment revenues $ 15,961 $ 4,572 $ 1,344 $ 21,877 Segment income (loss) from operations $ (133 ) $ 95 $ 567 $ 529 Income from equity method investments 3 14 69 86 Depreciation and amortization (a) 252 79 181 512 Capital expenditures and investments (b) 191 39 482 712 (a) Differences between segment totals and MPC consolidated totals represent amounts related to corporate and other unallocated items and are included in items not allocated to segments in the reconciliation below. (b) Capital expenditures include changes in capital accruals and investments in affiliates. See reconciliation from segment totals to MPC consolidated total capital expenditures below.
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 (In millions) 2019 2018 Segment income from operations $ 744 $ 529 Items not allocated to segments: Corporate and other unallocated items (a) (191 ) (89 ) Capline restructuring gain (b) 207 — Transaction-related costs (c) (91 ) — Income from operations 669 440 Net interest and other financial costs 306 183 Income before income taxes $ 363 $ 257 (a) Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets, except for corporate overhead expenses attributable to MPLX and ANDX, which are included in the Midstream segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Retail segments. (b) See Note 13 . (c) The transaction-related costs recognized in the first quarter largely relate to the recognition of an obligation for vacation benefits provided to former Andeavor employees.
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 (In millions) 2019 2018 Segment capital expenditures and investments $ 1,290 $ 712 Less investments in equity method investees 325 41 Plus items not allocated to segments: Corporate 10 18 Capitalized interest 31 18 Total capital expenditures (a) $ 1,006 $ 707 (a) Capital expenditures include changes in capital accruals. See Note 19 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

Net Interest and Other Financ_2

Net Interest and Other Financial Costs (Tables)	3 Months Ended
	Mar. 31, 2019
Other Income and Expenses [Abstract]
Net Interest And Other Financial Income (Costs)	Net interest and other financial costs were as follows: Three Months Ended (In millions) 2019 2018 Interest income $ (9 ) $ (20 ) Interest expense 340 213 Interest capitalized (32 ) (18 ) Pension and other postretirement non-service costs (a) (3 ) — Loss on extinguishment of debt — 4 Other financial costs 10 4 Net interest and other financial costs $ 306 $ 183 (a) See Note 21 .

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Summary Of Inventories	(In millions) March 31, December 31, Crude oil and refinery feedstocks $ 3,689 $ 3,655 Refined products 5,186 5,234 Materials and supplies 744 720 Merchandise 214 228 Total $ 9,833 $ 9,837

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Summary Of Property, Plant And Equipment	(In millions) March 31, December 31, Refining & Marketing $ 27,968 $ 27,590 Retail 6,681 6,637 Midstream 25,929 25,692 Corporate and Other 1,304 1,294 Total 61,882 61,213 Less accumulated depreciation 16,791 16,155 Property, plant and equipment, net $ 45,091 $ 45,058

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 and December 31, 2018 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. March 31, 2019 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 Assets: Commodity contracts $ 122 $ 18 $ — $ (128 ) $ 12 $ 42 Liabilities: Commodity contracts $ 142 $ 24 $ — $ (161 ) $ 5 $ — Embedded derivatives in commodity contracts — — 65 — 65 — December 31, 2018 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 Assets: Commodity contracts $ 370 $ 31 $ — $ (323 ) $ 78 $ 2 Liabilities: Commodity contracts $ 255 $ 37 $ — $ (284 ) $ 8 $ — Embedded derivatives in commodity contracts — — 61 — 61 — (a) Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of March 31, 2019 , cash collateral of $33 million was netted with the mark-to-market derivative liabilities. As of December 31, 2018 , cash collateral of $52 million was netted with mark-to-market derivative assets and $13 million was netted with mark-to-market derivative liabilities. (b) We have no derivative contracts that are subject to master netting arrangements reflected gross on the balance sheet.
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 net liabilities classified as Level 3 in the fair value hierarchy. Three Months Ended (In millions) 2019 2018 Beginning balance $ 61 $ 66 Unrealized and realized losses included in net income 6 (3 ) Settlements of derivative instruments (2 ) (3 ) Ending balance $ 65 $ 60 The amount of total losses for the period included in earnings attributable to the change in unrealized losses relating to assets still held at the end of period: $ 5 $ (3 )

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Classification of Fair Values of Derivative Instruments, Excluding Cash Collateral	The following table presents the fair value of derivative instruments as of March 31, 2019 and December 31, 2018 and the line items in the balance sheets in which the fair values are reflected. The fair value amounts below are presented on a gross basis and do not reflect the netting of asset and liability positions permitted under the terms of our master netting arrangements including cash collateral on deposit with, or received from, brokers. We offset the recognized fair value amounts for multiple derivative instruments executed with the same counterparty in our financial statements when a legal right of offset exists. As a result, the asset and liability amounts below will not agree with the amounts presented in our consolidated balance sheets. (In millions) March 31, 2019 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 139 $ 160 Other current liabilities (a) 1 14 Deferred credits and other liabilities (a) — 57 (In millions) December 31, 2018 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 400 $ 283 Other current liabilities (a) 1 16 Deferred credits and other liabilities (a) — 54 (a) Includes embedded derivatives.
Open Commodity Derivative Contracts	The table below summarizes open commodity derivative contracts for crude oil, refined products and blending products as of March 31, 2019 . Percentage of contracts that expire next quarter Position (Units in thousands of barrels) Long Short Exchange-traded (a) Crude oil 82.6% 49,844 58,466 Refined products 89.4% 11,373 9,945 Blending products 77.3% 4,688 4,866 OTC Crude oil —% 640 — Blending products —% 1,676 1,444 (a) Included in exchange-traded are spread contracts in thousands of barrels: Crude oil - 11,999 long and 3,980 short; Refined products - 300 long and 300 short; Blending products - 2,603 long and 2,506 short
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: Loss (In millions) Three Months Ended March 31, Income Statement Location 2019 2018 Sales and other operating revenues $ (20 ) $ (1 ) Cost of revenues (80 ) (27 ) Total $ (100 ) $ (28 )

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Outstanding Borrowings	Our outstanding borrowings at March 31, 2019 and December 31, 2018 consisted of the following: (In millions) March 31, December 31, Marathon Petroleum Corporation $ 9,120 $ 9,114 MPLX LP 14,283 13,856 ANDX LP 5,168 5,010 Total debt $ 28,571 $ 27,980 Unamortized debt issuance costs (126 ) (128 ) Unamortized discount (330 ) (328 ) Amounts due within one year (550 ) (544 ) Total long-term debt due after one year $ 27,565 $ 26,980
Schedule of Line of Credit Facilities [Table Text Block]	Available Capacity under our Facilities (Dollars in millions) Total Capacity Outstanding Borrowings Outstanding Letters of Credit Available Capacity Weighted Average Interest Rate Expiration MPC 364-day bank revolving credit facility $ 1,000 $ — $ — $ 1,000 — September 2019 MPC bank revolving credit facility 5,000 — 32 4,968 — October 2023 MPLX bank revolving credit facility 2,250 425 3 1,822 3.92 % July 2022 ANDX revolving & dropdown credit facilities (a) 2,100 1,404 — 696 4.32 % January 2021 Trade receivables securitization facility 750 — — 750 — July 2019 $ 11,100 $ 1,829 $ 35 $ 9,236 (a) Western Refining Southwest, Inc., a wholly-owned subsidiary of MPC and unitholder of ANDX, has guaranteed certain outstanding borrowings under the ANDX dropdown credit facility that were made in connection with the August 2018 dropdown transaction.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Products and Services [Table Text Block]	The following table presents our revenues disaggregated by product line. Three Months Ended (In millions) 2019 2018 Refined products $ 24,653 $ 16,158 Merchandise 1,464 1,130 Crude oil and refinery feedstocks 1,367 883 Midstream services, transportation and other 597 523 Sales and other operating revenues $ 28,081 $ 18,694

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Summary of Supplemental Cash Flow Information	Three Months Ended (In millions) 2019 2018 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 269 $ 212 Net income taxes paid to taxing authorities 42 6 Cash paid for amounts included in the measurement of lease liabilities Payments on operating leases 189 — Interest payments under finance lease obligations 8 — Net cash provided by financing activities included: Principal payments under finance lease obligations 10 — Non-cash investing and financing activities: Right of use assets obtained in exchange for new operating lease obligations 31 — Right of use assets obtained in exchange for new finance lease obligations 15 — Contribution of net assets to Capline LLC (a) 143 — Recognition of Capline LLC equity method investment (a) 350 — (a) See Note 13 .
Schedule of Cash and Cash Equivalents	(In millions) March 31, December 31, Cash and cash equivalents $ 877 $ 1,687 Restricted cash (a) 31 38 Cash, cash equivalents and restricted cash $ 908 $ 1,725 (a) The restricted cash balance is included within other current assets on the consolidated balance sheets.
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: Three Months Ended (In millions) 2019 2018 Additions to property, plant and equipment per the consolidated statements of cash flows $ 1,241 $ 755 Asset retirement expenditures — 1 Decrease in capital accruals (235 ) (49 ) Total capital expenditures $ 1,006 $ 707

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2019
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, 2017 $ (190 ) $ (48 ) $ 4 $ 3 $ (231 ) Other comprehensive loss before reclassifications — — (2 ) — (2 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (8 ) (1 ) — — (9 ) – actuarial loss (a) 9 — — — 9 – settlement loss (a) 1 — — — 1 Other — — — — — Tax effect (1 ) — — — (1 ) Other comprehensive income (loss) 1 (1 ) (2 ) — (2 ) Balance as of March 31, 2018 $ (189 ) $ (49 ) $ 2 $ 3 $ (233 ) (In millions) Pension Benefits Other Benefits Gain on Cash Flow Hedge Workers Compensation Total Balance as of December 31, 2018 $ (132 ) $ (23 ) $ 2 $ 9 $ (144 ) Other comprehensive loss before reclassifications (1 ) — — — (1 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (11 ) — — — (11 ) – actuarial loss (a) 4 — — — 4 – settlement loss (a) — — — — — Other — — — (1 ) (1 ) Tax effect 2 — — — 2 Other comprehensive loss (6 ) — — (1 ) (7 ) Balance as of March 31, 2019 $ (138 ) $ (23 ) $ 2 $ 8 $ (151 ) (a) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 21 .

Defined Benefit Pension and O_2

Defined Benefit Pension and Other Postretirement Plans (Tables)	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Costs	The following summarizes the components of net periodic benefit costs: Three Months Ended March 31, Pension Benefits Other Benefits (In millions) 2019 2018 2019 2018 Components of net periodic benefit cost: Service cost $ 58 $ 36 $ 8 $ 7 Interest cost 28 18 9 7 Expected return on plan assets (32 ) (26 ) — — Amortization – prior service credit (11 ) (8 ) — (1 ) – actuarial loss 4 9 — — – settlement loss — 1 — — Net periodic benefit cost $ 47 $ 30 $ 17 $ 13

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2019
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 three months ended March 31, 2019 : Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 8,724,595 $ 37.07 Granted 1,037,671 62.68 Exercised (229,169 ) 10.62 Forfeited or expired — — Outstanding at March 31, 2019 9,533,097 40.49
Summary of Restricted Stock Award Activity	The following table presents a summary of restricted stock and restricted stock unit award activity for the three months ended March 31, 2019 : Restricted Stock Restricted Stock Units Number of Shares Weighted Average Grant Date Fair Value Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2018 990,700 $ 57.23 4,226,856 $ 80.96 Granted 158,120 62.66 8,050 59.56 Vested (114,136 ) 49.58 (1,110,705 ) 82.43 Forfeited (12,622 ) 56.84 (46,923 ) 82.43 Outstanding at March 31, 2019 1,022,062 58.93 3,077,278 80.35
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 three months ended March 31, 2019 : Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2018 8,618,583 $ 0.79 Granted 6,200,000 0.72 Vested (2,280,333 ) 0.57 Forfeited (120,000 ) 0.84 Outstanding at March 31, 2019 12,418,250 0.79

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Lease, Cost	Under ASC 842, the components of lease cost were as follows: Three Months Ended (In millions) 2019 Finance lease cost: Amortization of right of use assets $ 14 Interest on lease liabilities 10 Operating lease cost 190 Variable lease cost 15 Short-term lease cost 152 Total lease cost $ 381
Supplemental Balance Sheet Disclosures [Text Block]	Supplemental balance sheet data related to leases were as follows: (In millions) March 31, 2019 Operating leases Assets Right of use assets $ 2,680 Liabilities Operating lease liabilities $ 613 Long-term operating lease liabilities 2,153 Total operating lease liabilities $ 2,766 Weighted average remaining lease term 6.5 years Weighted average discount rate 4.13 % Finance leases Assets Property, plant and equipment, gross $ 760 Accumulated depreciation 206 Property, plant and equipment, net $ 554 Liabilities Debt due within one year $ 45 Long-term debt 612 Total finance lease liabilities $ 657 Weighted average remaining lease term 13.2 years Weighted average discount rate 6.02 %
Schedule Of Future Minimum Lease Payments For Operating And Capital Leases Table [Text Block]	As of March 31, 2019 , maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Operating Finance 2019 $ 554 $ 57 2020 629 76 2021 545 69 2022 370 76 2023 262 83 2024 and thereafter 832 596 Gross lease payments 3,192 957 Less: imputed interest 426 300 Total lease liabilities $ 2,766 $ 657 Presented in accordance with ASC 840, future minimum commitments as of December 31, 2018 for operating lease obligations and capital lease obligations having initial or remaining non-cancellable lease terms in excess of one year were as follows: (In millions) Operating Capital 2019 $ 709 $ 70 2020 619 71 2021 553 66 2022 389 75 2023 295 82 2024 and thereafter 858 586 Total minimum lease payments $ 3,423 950 Less: imputed interest costs 301 Present value of net minimum lease payments $ 649
Schedule of Future Minimum Rental Payments Receivable for Operating Leases [Table Text Block]	The following is a schedule of minimum future rentals on the non‑cancellable operating leases as of March 31, 2019 : (In millions) 2019 $ 144 2020 168 2021 162 2022 160 2023 154 2024 and thereafter 1,205 Total minimum future rentals $ 1,993
Schedule of Property Subject to or Available for Operating Lease [Table Text Block]	The following schedule summarizes our investment in assets held for operating lease by major classes as of March 31, 2019 : (In millions) March 31, 2019 Natural gas gathering and NGL transportation pipelines and facilities $ 1,036 Natural gas processing facilities 642 Terminal and related assets 112 Land, building, office equipment and other 41 Property, plant and equipment 1,831 Less accumulated depreciation 261 Property, plant and equipment, net $ 1,570

Description of the Business a_3

Description of the Business and Basis of Presentation (Details) bbl / d in Millions	3 Months Ended
	Mar. 31, 2019Storebbl / drefinery
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Capacity | bbl / d	3
Number of refineries | refinery	16
Number of branded outlets	6,900
Number of retail transportation fuel and convenience stores	3,920
Number of direct dealer locations	1,060

Accounting Standards (Details)

Accounting Standards (Details) - Accounting Standards Update 2016-02 $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Minimum
New accounting pronouncement or change in accounting principle, effect of adoption, quantification	$ 2,790
Maximum
New accounting pronouncement or change in accounting principle, effect of adoption, quantification	$ 2,880

Master Limited Partnerships - M

Master Limited Partnerships - MPLX (Detail)	Mar. 31, 2019
MPLX
Noncontrolling Interest [Line Items]
MPC's partnership interest in MLP (in percentage)	64.00%

Master Limited Partnerships - D

Master Limited Partnerships - Dropdowns to MPLX and GP/IDR Exchange (Details) - MPLX shares in Millions, $ in Billions	Feb. 01, 2018USD ($)shares
MPLX 364-day term loan
Noncontrolling Interest [Line Items]
Maximum borrowing capacity | $	$ 4.1
Debt instrument, term	364 days
Cash and Cash Equivalents
Noncontrolling Interest [Line Items]
Cash consideration | $	$ 4.1
Limited Partner
Noncontrolling Interest [Line Items]
Units issued, number of units	112
Conversion of stock, units issued	275
General Partner
Noncontrolling Interest [Line Items]
Units issued, number of units	2

Master Limited Partnerships - A

Master Limited Partnerships - ANDX (Details)	Mar. 31, 2019shares
TexNew Mex units
Units outstanding	80,000
ANDX
MPC's partnership interest in MLP (in percentage)	64.00%

Master Limited Partnerships - N

Master Limited Partnerships - Noncontrolling Interest in MLPs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2017
Increase in MPC's additional paid-in capital, net of tax	$ 2	$ (546)
Additional Paid-in Capital
Increase due to the issuance of MPLX common units and general partner units to MPC	0		$ 1,114
Increase due to GP/IDR Exchange	0		1,808
Increase due to the issuance of MPLX & ANDX common units	4		4
Increase in MPC's additional paid-in capital	4		2,926
Tax impact	(1)		(546)
Increase in MPC's additional paid-in capital, net of tax	$ 3	$ 2,380	$ 2,380

Acquisitions - Acquisition of A

Acquisitions - Acquisition of Andeavor (Details) - USD ($) $ in Millions	Oct. 01, 2018	Mar. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 20,229	$ 20,184
Andeavor
Business Acquisition [Line Items]
Total fair value of consideration transferred	$ 23,460
Fair value of MPC shares issued	19,970
Cash payment to Andeavor stockholders	3,490
Goodwill	16,380
Goodwill, expected tax deductible amount	893
Andeavor | Refining & Marketing
Business Acquisition [Line Items]
Goodwill	4,780
Andeavor | Midstream
Business Acquisition [Line Items]
Goodwill	7,720
Andeavor | Retail
Business Acquisition [Line Items]
Goodwill	$ 3,880

Acquisitions - Schedule of Asse

Acquisitions - Schedule of Assets Acquired and Liabilities Assumed - Andeavor (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018	Oct. 01, 2018
Business Acquisition [Line Items]
Goodwill		$ 20,229	$ 20,184
Andeavor
Business Acquisition [Line Items]
Cash and cash equivalents				$ 382
Receivables				2,742
Inventories				5,196
Other current assets				378
Equity method investments				865
Property, plant and equipment, net				16,544
Other noncurrent assets	[1]			3,086
Total assets acquired				29,193
Accounts payable				4,003
Payroll and benefits payable				348
Accrued taxes				590
Debt due within one year				34
Other current liabilities				415
Long-term debt				8,876
Deferred income taxes				1,631
Defined benefit postretirement plan obligations				432
Deferred credit and other liabilities				720
Noncontrolling interests				5,062
Total liabilities and noncontrolling interest assumed				22,111
Net assets acquired excluding goodwill				7,082
Goodwill				16,380
Net assets acquired				23,462
Andeavor | As originally reported
Business Acquisition [Line Items]
Cash and cash equivalents				382
Receivables				2,744
Inventories				5,204
Other current assets				378
Equity method investments				865
Property, plant and equipment, net				16,545
Other noncurrent assets	[1]			3,086
Total assets acquired				29,204
Accounts payable				4,003
Payroll and benefits payable				348
Accrued taxes				590
Debt due within one year				34
Other current liabilities				392
Long-term debt				8,875
Deferred income taxes				1,609
Defined benefit postretirement plan obligations				432
Deferred credit and other liabilities				714
Noncontrolling interests				5,059
Total liabilities and noncontrolling interest assumed				22,056
Net assets acquired excluding goodwill				7,148
Goodwill				16,314
Net assets acquired				23,462
Andeavor | Adjustments
Business Acquisition [Line Items]
Cash and cash equivalents				0
Receivables				(2)
Inventories				(8)
Other current assets				0
Equity method investments				0
Property, plant and equipment, net				(1)
Other noncurrent assets	[1]			0
Total assets acquired				(11)
Accounts payable				0
Payroll and benefits payable				0
Accrued taxes				0
Debt due within one year				0
Other current liabilities				23
Long-term debt				1
Deferred income taxes				22
Defined benefit postretirement plan obligations				0
Deferred credit and other liabilities				6
Noncontrolling interests				3
Total liabilities and noncontrolling interest assumed				55
Net assets acquired excluding goodwill				(66)
Goodwill		$ 32		66
Net assets acquired				$ 0
[1]	Includes intangible assets

Acquisition - Pro Forma Informa

Acquisition - Pro Forma Information - Andeavor (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Sales and other operating revenues	$ 28,081	$ 18,694
Net income (loss) attributable to MPC	$ (7)	37
Andeavor
Business Acquisition [Line Items]
Sales and other operating revenues		29,206
Net income (loss) attributable to MPC		$ 26

Acquisition - Acquisition of Ex

Acquisition - Acquisition of Express Mart (Details) $ in Millions	Nov. 16, 2018USD ($)Store	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Goodwill		$ 20,229	$ 20,184
Express Mart
Business Acquisition [Line Items]
Number of stores | Store	78
Cash consideration	$ 266
Property, plant and equipment, net	97
Inventories	9
Finite-lived intangibles	2
Goodwill	$ 158

Acquisitions - Acquisition of M

Acquisitions - Acquisition of Mt. Airy Terminal (Details) bbl / d in Thousands, bbl in Millions, $ in Millions	Sep. 26, 2018USD ($)bbl / dbbl	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Goodwill		$ 20,229	$ 20,184
Mt. Airy Terminal
Storage capacity | bbl	4
Barrels handled | bbl / d	120
Mt. Airy Terminal | MPLX
Cash consideration	$ 446
Property, plant and equipment, net	336
Goodwill	121
Mt. Airy Terminal | As originally reported | MPLX
Cash consideration	451
Mt. Airy Terminal | Adjustments | MPLX
Cash consideration	$ 5

Variable Interest Entities - Co

Variable Interest Entities - Consolidated VIEs (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents		$ 877	$ 1,687
Receivables, less allowance for doubtful accounts		6,893	5,853
Inventories		9,833	9,837
Other current assets		548	646
Equity method investments		6,558	5,898
Property, plant and equipment, net		45,091	45,058
Goodwill		20,229	20,184
Right of use assets		2,680	0
Other noncurrent assets		3,727	3,777
Liabilities
Accounts payable		10,568	9,366
Payroll and benefits payable		958	1,152
Accrued taxes		1,529	1,446
Debt due within one year		550	544
Operating lease liabilities		613	0
Other current liabilities		929	708
Long-term debt		27,565	26,980
Defined benefit postretirement plan obligations		1,567	1,509
Long-term operating lease liabilities		2,153	0
Deferred credits and other liabilities		1,131	1,318
Variable Interest Entity, Primary Beneficiary [Member] | MPLX
Assets
Cash and cash equivalents		93	68
Receivables, less allowance for doubtful accounts		372	425
Inventories		74	77
Other current assets		34	45
Equity method investments		4,270	4,174
Property, plant and equipment, net		14,816	14,639
Goodwill		2,581	2,586
Right of use assets		262	0
Other noncurrent assets		448	458
Liabilities
Accounts payable		583	776
Payroll and benefits payable		4	2
Accrued taxes		40	48
Debt due within one year		1	1
Operating lease liabilities		46	0
Other current liabilities		189	177
Long-term debt		13,832	13,392
Deferred income taxes		12	13
Long-term operating lease liabilities		216	0
Deferred credits and other liabilities		289	276
Variable Interest Entity, Primary Beneficiary [Member] | ANDX
Assets
Cash and cash equivalents	[1]	29	10
Receivables, less allowance for doubtful accounts	[1]	248	199
Inventories	[1]	21	22
Other current assets	[1]	37	57
Equity method investments	[1]	602	602
Property, plant and equipment, net	[1]	6,882	6,845
Goodwill	[1]	1,052	1,051
Right of use assets	[1]	122	0
Other noncurrent assets	[1]	1,235	1,242
Liabilities
Accounts payable	[1]	177	215
Payroll and benefits payable	[1]	1	10
Accrued taxes	[1]	20	23
Debt due within one year	[1]	503	504
Operating lease liabilities	[1]	12	0
Other current liabilities	[1]	117	77
Long-term debt	[1]	4,629	4,469
Deferred income taxes	[1]	1	1
Long-term operating lease liabilities	[1]	109	0
Deferred credits and other liabilities	[1]	$ 66	$ 68
[1]	The balances reflected here are ANDX’s historical balances as the preliminary purchase accounting adjustments related to ANDX’s assets and liabilities in connection with the Andeavor acquisition and reflected on our consolidated balance sheets as of December 31, 2018 and March 31, 2019 have not yet been pushed down to this subsidiary.

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Related Party Transactions [Abstract]
Sales to related parties	[1]	$ 186	$ 172
Purchases from related parties	[2]	$ 204	$ 141
[1]	Sales to related parties consists primarily of sales of refined products to PFJ Southeast, an equity affiliate which owns and operates travel plazas primarily in the Southeast region of the United States.
[2]	We obtain utilities, transportation services and purchase ethanol from certain of our equity affiliates.

Related Party Transactions - Su

Related Party Transactions - Summarized Financial Information for Significant Equity Affiliates (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transactions [Abstract]
Revenues and other income	$ 1,628	$ 1,503
Income from operations	336	254
Net income	$ 314	$ 274

Income (Loss) Per Common Shar_2

Income (Loss) Per Common Share - Summary of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Basic earnings (loss) per share:
Net income (loss) attributable to MPC	$ (7)	$ 37
Income allocated to participating securities	0	0
Income (loss) available to common stockholders – basic	$ (7)	$ 37
Weighted average common shares outstanding (in shares)	673	476
Basic earnings (loss) per share	$ (0.01)	$ 0.08
Diluted earnings (loss) per share:
Net income (loss) attributable to MPC	$ (7)	$ 37
Income allocated to participating securities	0	0
Income (loss) available to common stockholders – diluted	$ (7)	$ 37
Weighted average common shares outstanding (in shares)	673	476
Effect of dilutive securities (in shares)	0	4
Weighted average common shares, including dilutive effect (in shares)	673	480
Diluted earnings (loss) per share	$ (0.01)	$ 0.08

Income (Loss) Per Common Shar_3

Income (Loss) Per Common Share - Anti-dilutive Shares (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock Based Compensation Expense [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issuable under stock-based compensation plans	7	0

Equity - Additional Information

Equity - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2019	Mar. 31, 2019	Mar. 31, 2018
Number of shares repurchased		14,000,000	19,000,000
Cash paid for shares repurchased		$ 885	$ 1,327
Stock repurchase program, remaining authorized repurchase amount		$ 4,020
Forecast
Number of shares repurchased	493,625
Cash paid for shares repurchased	$ 30

Equity - Share Repurchases (Det

Equity - Share Repurchases (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Equity [Abstract]
Number of shares repurchased	14	19
Cash paid for shares repurchased	$ 885	$ 1,327
Average cost per share	$ 62.98	$ 68.74

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019Segmentrefinery
Segment Reporting [Abstract]
Number of reportable segments | Segment	3
Number of refineries | refinery	16

Segment Information - Income Fr

Segment Information - Income From Operations Attributable To Operating Segments (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Sales and other operating revenues		$ 28,081	$ 18,694
Sales to related parties	[1]	186	172
Income (loss) from operations		669	440
Income from equity method investments		99	86
Depreciation and amortization		919	528
Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues		5,663	3,011
Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues		33,930	21,877
Income (loss) from operations		744	529
Income from equity method investments		99	86
Depreciation and amortization	[2]	860	512
Capital expenditures and investments	[3]	1,290	712
Refining & Marketing
Segment Reporting Information [Line Items]
Sales and other operating revenues		19,751	13,412
Sales to related parties		183	170
Refining & Marketing | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues		4,429	2,379
Refining & Marketing | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues		24,363	15,961
Income (loss) from operations		(334)	(133)
Income from equity method investments		1	3
Depreciation and amortization		427	252
Capital expenditures and investments		394	191
Retail
Segment Reporting Information [Line Items]
Sales and other operating revenues		7,373	4,569
Sales to related parties		3	2
Retail | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues		2	1
Retail | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues		7,378	4,572
Income (loss) from operations		170	95
Income from equity method investments		17	14
Depreciation and amortization		126	79
Capital expenditures and investments		73	39
Midstream
Segment Reporting Information [Line Items]
Sales and other operating revenues		957	713
Sales to related parties		0	0
Midstream | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues		1,232	631
Midstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues		2,189	1,344
Income (loss) from operations		908	567
Income from equity method investments		81	69
Depreciation and amortization		307	181
Capital expenditures and investments		823	482
Reportable Segment
Segment Reporting Information [Line Items]
Sales and other operating revenues		$ 28,081	$ 18,694
[1]	Sales to related parties consists primarily of sales of refined products to PFJ Southeast, an equity affiliate which owns and operates travel plazas primarily in the Southeast region of the United States.
[2]	Differences between segment totals and MPC consolidated totals represent amounts related to corporate and other unallocated items and are included in items not allocated to segments in the reconciliation below.
[3]	Capital expenditures include changes in capital accruals and investments in affiliates. See reconciliation from segment totals to MPC consolidated total capital expenditures below.

Segment Information - Reconcili

Segment Information - Reconciliation Of Segment Income From Operations To Income Before Income Taxes (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from operations		$ 669		$ 440
Net interest and other financial costs		306		183
Income before income taxes		363		257
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from operations		744		529
Corporate and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) from operations	[1]	(191)		(89)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Capline restructuring gain		207	[2]	0
Transaction-related costs(c)		$ (91)		$ 0
[1]	Corporate and other unallocated items consists primarily of MPC’s corporate administrative expenses and costs related to certain non-operating assets, except for corporate overhead expenses attributable to MPLX and ANDX, which are included in the Midstream segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Retail segments.
[2]	See Note 13.

Segment Information - Reconci_2

Segment Information - Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Plus items not allocated to segments:
Capital expenditures	[1]	$ 1,006	$ 707
Operating Segments
Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures [Line Items]
Capital expenditures and investments	[2]	1,290	712
Less investments in equity method investees		325	41
Corporate and Other
Plus items not allocated to segments:
Corporate		10	18
Capitalized interest		$ 31	$ 18
[1]	Capital expenditures include changes in capital accruals. See Note 19 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.
[2]	Capital expenditures include changes in capital accruals and investments in affiliates. See reconciliation from segment totals to MPC consolidated total capital expenditures below.

Net Interest And Other Financ_3

Net Interest And Other Financial Costs (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Other Income and Expenses [Abstract]
Interest income		$ (9)	$ (20)
Interest expense		340	213
Interest capitalized		(32)	(18)
Non-Service Pension and Postretirement Expense	[1]	(3)
Pension and other postretirement non-service costs	[1]		0
Loss on extinguishment of debt		0	4
Other financial costs		10	4
Net interest and other financial costs		$ 306	$ 183
[1]	See Note 21.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Combined federal, state and foreign income tax rate	29.00%	9.00%
Federal statutory income tax rate, percent	21.00%
Unrecognized benefits	$ 231

Income Taxes - Out of Period Ad

Income Taxes - Out of Period Adjustment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Oct. 01, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes	$ 104	$ 22
Goodwill	20,229		$ 20,184
Andeavor
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Goodwill				$ 16,380
Andeavor | Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes	36
Deferred tax liabilities	68
Goodwill	$ 32			$ 66

Inventories - Summary Of Invent

Inventories - Summary Of Inventories (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Crude oil and refinery feedstocks	$ 3,689	$ 3,655
Refined products	5,186	5,234
Materials and supplies	744	720
Merchandise	214	228
Total	$ 9,833	$ 9,837

Inventories - Additional Inform

Inventories - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Inventory Disclosure [Abstract]
Impact on income as a result of LIFO liquidations	$ 0

Equity Method Investments (Deta

Equity Method Investments (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Contribution of net assets to Capline LLC		$ 143	[1]	$ 0
Recognition of Capline LLC equity method investment		$ 350	[1]	$ 0
Capline
Undivided joint interest, ownership percentage		33.00%
Equity method investments, ownership percentage		33.00%
Contribution of net assets to Capline LLC	[1]	$ 143
Recognition of Capline LLC equity method investment	[1]	350
Capline restructuring gain	[1]	$ 207
[1]	See Note 13.

Property, Plant And Equipment -

Property, Plant And Equipment - Summary Of Property, Plant And Equipment (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 61,882	$ 61,213
Less accumulated depreciation	16,791	16,155
Property, plant and equipment, net	45,091	45,058
Operating Segments | Refining & Marketing
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	27,968	27,590
Operating Segments | Retail
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,681	6,637
Operating Segments | Midstream
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	25,929	25,692
Corporate and Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,304	$ 1,294

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Mar. 31, 2019		Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash collateral netted with derivative liabilities		$ 33		$ 13
Cash collateral netted with derivatives assets				52
Fair Value, Measurements, Recurring | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - netting and collateral		(128)	[1]	(323)
Commodity derivative instruments, assets - net carrying value on balance sheet	[2]	12		78
Commodity derivative instruments, assets - collateral pledged not offset		42		2
Commodity derivative instruments, liabilities - netting and collateral		(161)	[1]	(284)
Commodity derivative instruments, liabilities - net carrying value on balance sheet	[2]	5		8
Commodity derivative instruments, liabilities - collateral pledged not offset		0		0
Fair Value, Measurements, Recurring | Embedded derivatives in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - netting and collateral		0		0
Commodity derivative instruments, liabilities - net carrying value on balance sheet	[2]	65		61
Commodity derivative instruments, liabilities - collateral pledged not offset		0		0
Fair Value, Measurements, Recurring | Level 1 | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		122		370
Commodity derivative instruments, liabilities - gross		142		255
Fair Value, Measurements, Recurring | Level 1 | Embedded derivatives in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		0		0
Fair Value, Measurements, Recurring | Level 2 | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		18		31
Commodity derivative instruments, liabilities - gross		24		37
Fair Value, Measurements, Recurring | Level 2 | Embedded derivatives in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		0		0
Fair Value, Measurements, Recurring | Level 3 | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		0		0
Commodity derivative instruments, liabilities - gross		0		0
Fair Value, Measurements, Recurring | Level 3 | Embedded derivatives in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		$ 65		$ 61
[1]	Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of March 31, 2019, cash collateral of $33 million was netted with the mark-to-market derivative liabilities. As of December 31, 2018, cash collateral of $52 million was netted with mark-to-market derivative assets and $13 million was netted with mark-to-market derivative liabilities.
[2]	We have no derivative contracts that are subject to master netting arrangements reflected gross on the balance sheet.

Fair Value Measurements - Recur

Fair Value Measurements - Recurring Narrative (Detail)	3 Months Ended
	Mar. 31, 2019USD ($)
Embedded derivatives in commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Embedded derivative renewal term	5 years
Level 3 | Commodity derivatives | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward commodity price	$ 0.60
Level 3 | Commodity derivatives | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward commodity price	$ 1.25
Level 3 | Embedded derivatives in commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of renewal first term	91.00%
Probability of renewal second term	82.00%

Fair Value Measurements - Recon

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
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 61	$ 66
Unrealized and realized losses included in net income	6	(3)
Settlements of derivative instruments	(2)	(3)
Ending balance	$ 65	$ 60

Fair Value Measurements - Losse

Fair Value Measurements - Losses Included in Earnings Relating to Assets Still Held at End of Period (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value Disclosures [Abstract]
The amount of total losses for the period included in earnings attributable to the change in unrealized losses relating to assets still held at the end of period:	$ 5	$ (3)

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values - Reported (Detail) - USD ($) $ in Billions	Mar. 31, 2019	Dec. 31, 2018
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 28.5	$ 26.5
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 27.6	$ 27

Derivatives - Classification of

Derivatives - Classification of Gross Fair Values of Derivative Instruments, Excluding Cash Collateral (Detail) - Commodity derivatives - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Other current assets
Derivatives, Fair Value [Line Items]
Asset		$ 139	$ 400
Liability		160	283
Other current liabilities(a)
Derivatives, Fair Value [Line Items]
Asset		1	1
Liability	[1]	14	16
Deferred credits and other liabilities
Derivatives, Fair Value [Line Items]
Asset		0	0
Liability	[1]	$ 57	$ 54
[1]	Includes embedded derivatives.

Derivatives - Open Commodity De

Derivatives - Open Commodity Derivative Contracts (Details) gal in Thousands, bbl in Thousands	3 Months Ended
	Mar. 31, 2019bblgal
Exchange Traded | Crude oil
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	82.60%
Exchange Traded | Crude oil | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	49,844	[1]
Exchange Traded | Crude oil | Long | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	11,999
Exchange Traded | Crude oil | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels) | gal	58,466	[1]
Exchange Traded | Crude oil | Short | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	3,980
Exchange Traded | Refined products
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	89.40%
Exchange Traded | Refined products | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	11,373	[1]
Exchange Traded | Refined products | Long | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	300
Exchange Traded | Refined products | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels) | gal	9,945	[1]
Exchange Traded | Refined products | Short | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	300
Exchange Traded | Blending products
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	77.30%
Exchange Traded | Blending products | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	4,688	[1]
Exchange Traded | Blending products | Long | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	2,603
Exchange Traded | Blending products | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels) | gal	4,866	[1]
Exchange Traded | Blending products | Short | Spread Contracts
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	2,506
Over the Counter | Crude oil
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	0.00%
Over the Counter | Crude oil | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	640
Over the Counter | Crude oil | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	0
Over the Counter | Blending products
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	0.00%
Over the Counter | Blending products | Long
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels)	1,676
Over the Counter | Blending products | Short
Derivative [Line Items]
Notional contracts (in thousands of Total Barrels) | gal	1,444
[1]	Included in exchange-traded are spread contracts in thousands of barrels: Crude oil - 11,999 long and 3,980 short; Refined products - 300 long and 300 short; Blending products - 2,603 long and 2,506 short

Derivatives - Effect of Commodi

Derivatives - Effect of Commodity Derivative Instruments in Statements of Income (Detail) - Commodity derivatives - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Loss	$ (100)	$ (28)
Sales and other operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Loss	(20)	(1)
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Loss	$ (80)	$ (27)

Debt - Outstanding Borrowings (

Debt - Outstanding Borrowings (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Total debt	$ 28,571	$ 27,980
Unamortized debt issuance costs	(126)	(128)
Unamortized discount	(330)	(328)
Amounts due within one year	(550)	(544)
Total long-term debt due after one year	27,565	26,980
Marathon Petroleum Corporation
Total debt	9,120	9,114
MPLX LP
Total debt	14,283	13,856
ANDX LP
Total debt	$ 5,168	$ 5,010

Debt - Available Capacity under

Debt - Available Capacity under our Facilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
Total Capacity	$ 11,100
Outstanding Borrowings	1,829
Outstanding Letters of Credit	35
Available Capacity	9,236
MPC 364-day bank revolving credit facility
Debt Instrument [Line Items]
Total Capacity	1,000
Outstanding Borrowings	0
Outstanding Letters of Credit	0
Available Capacity	$ 1,000
Weighted Average Interest Rate	0.00%
Expiration	Sep. 30, 2019
MPC bank revolving credit facility
Debt Instrument [Line Items]
Total Capacity	$ 5,000
Outstanding Borrowings	0
Outstanding Letters of Credit	32
Available Capacity	$ 4,968
Weighted Average Interest Rate	0.00%
Expiration	Oct. 1, 2023
MPLX bank revolving credit facility
Debt Instrument [Line Items]
Total Capacity	$ 2,250
Outstanding Borrowings	425
Outstanding Letters of Credit	3
Available Capacity	$ 1,822
Weighted Average Interest Rate	3.92%
Expiration	Jul. 21, 2022
ANDX revolving & dropdown credit facilities(a)
Debt Instrument [Line Items]
Total Capacity	$ 2,100
Outstanding Borrowings	1,404	[1]
Outstanding Letters of Credit	0
Available Capacity	$ 696
Weighted Average Interest Rate	4.32%
Expiration	Jan. 29, 2021
Trade receivables securitization facility
Debt Instrument [Line Items]
Total Capacity	$ 750
Outstanding Borrowings	0
Outstanding Letters of Credit	0
Available Capacity	$ 750
Weighted Average Interest Rate	0.00%
Expiration	Jul. 19, 2019
[1]	Western Refining Southwest, Inc., a wholly-owned subsidiary of MPC and unitholder of ANDX, has guaranteed certain outstanding borrowings under the ANDX dropdown credit facility that were made in connection with the August 2018 dropdown transaction.

Revenue - Disaggregated by Prod

Revenue - Disaggregated by Product Line (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Sales and other operating revenues	$ 28,081	$ 18,694
Refined products
Sales and other operating revenues	24,653	16,158
Merchandise
Sales and other operating revenues	1,464	1,130
Crude oil and refinery feedstocks
Sales and other operating revenues	1,367	883
Midstream services, transportation and other
Sales and other operating revenues	$ 597	$ 523

Revenue (Details)

Revenue (Details) $ in Millions	Mar. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Matching buy/sell receivables	$ 1,980
Income taxes receivable	$ 76

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$ 269		$ 212
Net income taxes paid to taxing authorities	42		6
Payments on operating leases	189		0
Interest payments under finance lease obligations	8		0
Net cash provided by financing activities included:
Principal payments under finance lease obligations	10		0
Non-cash investing and financing activities:
Right of use assets obtained in exchange for new operating lease obligations	31		0
Right of use assets obtained in exchange for new finance lease obligations	15		0
Contribution of net assets to Capline LLC	143	[1]	0
Recognition of Capline LLC equity method investment	$ 350	[1]	$ 0
[1]	See Note 13.

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Cash, Cash Equalivalents and Restricted Cash (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents		$ 877	$ 1,687
Restricted cash	[1]	31	38
Cash, cash equivalents and restricted cash		$ 908	$ 1,725	$ 4,657	$ 3,015
[1]	The restricted cash balance is included within other current assets on the consolidated balance sheets

Supplemental Cash Flow Inform_5

Supplemental Cash Flow Information - Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Additions to property, plant and equipment per the consolidated statements of cash flows		$ 1,241	$ 755
Asset retirement expenditures		0	1
Decrease in capital accruals		(235)	(49)
Capital expenditures	[1]	$ 1,006	$ 707
[1]	Capital expenditures include changes in capital accruals. See Note 19 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (144)	$ (231)
Other comprehensive loss before reclassifications		(1)	(2)
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit		(11)	(9)
Amortization - actuarial loss		4	9
Amortization - settlement loss		0	1
Other		(1)	0
Tax effect		2	(1)
Other comprehensive loss		(7)	(2)
Ending balance		(151)	(233)
Accumulated Defined Benefit Plans Adjustment | Pension Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(132)	(190)
Other comprehensive loss before reclassifications		(1)	0
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]	(11)	(8)
Amortization - actuarial loss	[1]	4	9
Amortization - settlement loss	[1]	0	1
Tax effect		2	(1)
Other comprehensive loss		(6)	1
Ending balance		(138)	(189)
Accumulated Defined Benefit Plans Adjustment | Other Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(23)	(48)
Other comprehensive loss before reclassifications		0	0
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]	0	(1)
Amortization - actuarial loss	[1]	0	0
Amortization - settlement loss		0	0
Tax effect		0	0
Other comprehensive loss		0	(1)
Ending balance		(23)	(49)
Gain on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		2	4
Other comprehensive loss before reclassifications		0	(2)
Amounts reclassified from accumulated other comprehensive loss:
Tax effect		0	0
Other comprehensive loss		0	(2)
Ending balance		2	2
Workers Compensation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		9	3
Other comprehensive loss before reclassifications		0	0
Amounts reclassified from accumulated other comprehensive loss:
Other		(1)	0
Tax effect		0	0
Other comprehensive loss		(1)	0
Ending balance		$ 8	$ 3
[1]	These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 21.

Defined Benefit Pension and O_3

Defined Benefit Pension and Other Postretirement Plans - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Benefits
Components of net periodic benefit cost:
Service cost	$ 58	$ 36
Interest cost	28	18
Expected return on plan assets	(32)	(26)
Amortization – prior service credit	(11)	(8)
Amortization – actuarial loss	4	9
Amortization - settlement loss	0	1
Net periodic benefit cost	47	30
Other Benefits
Components of net periodic benefit cost:
Service cost	8	7
Interest cost	9	7
Expected return on plan assets	0	0
Amortization – prior service credit	0	(1)
Amortization – actuarial loss	0	0
Amortization - settlement loss	0	0
Net periodic benefit cost	$ 17	$ 13

Defined Benefit Pension and O_4

Defined Benefit Pension and Other Postretirement Plans - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0
Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	3
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	$ 11

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Summary of Stock Option Award Activity (Detail) - Stock Options	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of Shares
Outstanding, beginning balance | shares	8,724,595
Granted | shares	1,037,671
Exercised | shares	(229,169)
Forfeited or expired | shares	0
Outstanding, ending balance | shares	9,533,097
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 37.07
Granted (in USD per share) | $ / shares	62.68
Exercised (in USD per share) | $ / shares	10.62
Forfeited or expired (in USD per share) | $ / shares	0
Outstanding, ending balance (in USD per share) | $ / shares	$ 40.49

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Narrative (Detail)	3 Months Ended
	Mar. 31, 2019$ / shares
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value (in USD per share)	$ 14.34
Performance Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in USD per share)	$ 0.72

Stock-Based Compensation Plan_4

Stock-Based Compensation Plans - Summary of Restricted Stock Award Activity (Detail)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Restricted Stock
Number of Shares
Outstanding, beginning balance | shares	990,700
Granted | shares	158,120
RS Vested/RSUs Issued | shares	(114,136)
Forfeited | shares	(12,622)
Outstanding, ending balance | shares	1,022,062
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share) | $ / shares	$ 57.23
Granted (in USD per share) | $ / shares	62.66
RS's Vested/RSU's Issued (in USD per share) | $ / shares	49.58
Forfeited (in USD per share) | $ / shares	56.84
Outstanding, ending balance (in USD per share) | $ / shares	$ 58.93
Restricted Stock Units
Number of Shares
Outstanding, beginning balance | shares	4,226,856
Granted | shares	8,050
RS Vested/RSUs Issued | shares	(1,110,705)
Forfeited | shares	(46,923)
Outstanding, ending balance | shares	3,077,278
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share) | $ / shares	$ 80.96
Granted (in USD per share) | $ / shares	59.56
RS's Vested/RSU's Issued (in USD per share) | $ / shares	82.43
Forfeited (in USD per share) | $ / shares	82.43
Outstanding, ending balance (in USD per share) | $ / shares	$ 80.35

Stock-Based Compensation Plan_5

Stock-Based Compensation Plans - Summary of Performance Unit Awards (Detail) - Performance Unit Awards	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of Units
Outstanding, beginning balance | shares	8,618,583
Granted | shares	6,200,000
Vested | shares	(2,280,333)
Forfeited | shares	(120,000)
Outstanding, ending balance | shares	12,418,250
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share) | $ / shares	$ 0.79
Granted (in USD per share) | $ / shares	0.72
Vested (in USD per share) | $ / shares	0.57
Forfeited (in USD per share) | $ / shares	0.84
Outstanding, ending balance (in USD per share) | $ / shares	$ 0.79

Lessee Narrative (Details)

Lessee Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Minimum
Term of agreements	1 year
Renewal term options	1 year
Maximum
Term of agreements	60 years
Renewal term options	49 years

Components of Lease Cost (Detai

Components of Lease Cost (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Finance lease cost:
Amortization of right of use assets	$ 14
Interest on lease liabilities	10
Operating lease cost	190
Variable lease cost	15
Short-term lease cost	152
Total lease cost	$ 381

Leases Supplemental Balance She

Leases Supplemental Balance Sheet Disclosure (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating leases
Right of use assets	$ 2,680	$ 0
Operating lease liabilities	613	0
Long-term operating lease liabilities	2,153	0
Total operating lease liabilities	$ 2,766
Weighted average remaining lease term	6 years 6 months 11 days
Weighted average discount rate	4.13%
Finance leases
Property, plant and equipment, gross	$ 61,882	61,213
Less accumulated depreciation	16,791	16,155
Property, plant and equipment, net	45,091	45,058
Debt due within one year	550	544
Long-term debt	27,565	26,980
Total finance lease liabilities	$ 657	$ 649
Weighted average remaining lease term	13 years 1 month 25 days
Weighted average discount rate	6.02%
Finance Lease
Finance leases
Property, plant and equipment, gross	$ 760
Less accumulated depreciation	206
Property, plant and equipment, net	554
Debt due within one year	45
Long-term debt	612
Total finance lease liabilities	$ 657

Schedule of Minimum Lease Payme

Schedule of Minimum Lease Payments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating leases
2019	$ 554	$ 709
2020	629	619
2021	545	553
2022	370	389
2023	262	295
2024 and thereafter	832	858
Gross lease payments	3,192	3,423
Less: imputed interest	426
Total operating lease liabilities	2,766
Finance Lease Liabilities, Payments, Due [Abstract]
2019	57	70
2020	76	71
2021	69	66
2022	76	75
2023	83	82
2024 and thereafter	596	586
Gross lease payments	957	950
Less: imputed interest	300	301
Total finance lease liabilities	$ 657	$ 649

Lessor Narrative (Details)

Lessor Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Lease revenue	$ 60

Schedule of Future Future Renta

Schedule of Future Future Rental Payments Receivable for Operating Leases (Details) $ in Millions	Mar. 31, 2019USD ($)
Leases [Abstract]
2019	$ 144
2020	168
2021	162
2022	160
2023	154
2024 and thereafter	1,205
Total minimum future rentals	$ 1,993

Schedule of Property Subject to

Schedule of Property Subject to or Available for Operating Lease (Details) $ in Millions	Mar. 31, 2019USD ($)
Property, plant and equipment	$ 1,831
Less accumulated depreciation	261
Property, plant and equipment, net	1,570
Natural gas gathering and NGL transportation pipelines and facilities
Property, plant and equipment	1,036
Natural gas processing facilities
Property, plant and equipment	642
Terminal and related assets
Property, plant and equipment	112
Land, building, office equipment and other
Property, plant and equipment	$ 41

Commitments and Contingencies (

Commitments and Contingencies (Detail)	3 Months Ended
	Mar. 31, 2019
Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, inestimable loss	<div style="line-height:120%;padding-top:6px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">For matters for which we have not recorded a liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings.</font></div></div>" id="sjs-B5">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">For matters for which we have not recorded a liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings.&lt;/font>&lt;/div>&lt;/div>

Commitments and Contingencies -

Commitments and Contingencies - Environmental Matters (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Accrued liabilities for remediation	$ 451	$ 455
Receivables for recoverable costs	$ 33	$ 35

Commitments and Contingencies_2

Commitments and Contingencies - Other Lawsuits (Details) - Pending Litigation - Emergency Pricing And Consumer Protection Laws $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Loss Contingencies [Line Items]
Plaintiff	Commonwealth of Kentucky
Damages sought	$ 89
Loss contingency, period of occurrence	during September and October 2005

Commitments and Contingencies_3

Commitments and Contingencies - Guarantees (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Other Guarantees
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 123
LOOP and LOCAP LLC | Guarantee of Indebtedness of Others | Financial Guarantee
Loss Contingencies [Line Items]
Expiration	Dec. 31, 2037
Maximum potential undiscounted payments	$ 171
Bakken Pipeline System | Other Guarantees
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 230
Crowley Ocean Partners
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	50.00%
Crowley Ocean Partners | Guarantee of Indebtedness of Others | Financial Guarantee
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 135
Crowley Ocean Partners | Guarantee of Indebtedness of Others | Financial Guarantee | Crowley Term Loan
Loss Contingencies [Line Items]
Maximum borrowing capacity	$ 325
Crowley Blue Water Partners
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	50.00%
Crowley Blue Water Partners | Guarantee of Indebtedness of Others | Financial Guarantee
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 125
Indirect Ownership Interest | Bakken Pipeline System
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	9.00%
Marathon Oil Companies | Indemnification Agreement
Loss Contingencies [Line Items]
Guarantee obligation current carrying value	$ 1

Commitments and Contingencies_4

Commitments and Contingencies - Contractual Commitments and Contingencies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees	$ 1,060

Subsequent Event Subsequent Eve

Subsequent Event Subsequent Event (Details) - Subsequent Event [Member]	May 08, 2019shares
Public
Subsequent Event [Line Items]
Common Units Conversion Ratio	1.135
Nonpublic
Subsequent Event [Line Items]
Common Units Conversion Ratio	1.0328